Electrical Basis of Design - OXY

8/10/2019 Electrical Basis of Design - OXY

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OCCIDENTAL PETROLEUM

OF QATAR LTD

PARNO.

DISC LOCATION I.D. DOC TYPE SEQUENTIAL No. SHEET No.

DOCUMENTNUMBER

000000-4-XPS1-BD-0001-001

DOCUMENTTYPE ELECTRICAL BASIS OF DESIGN

TITLE OCCIDENTAL MANAGED FACILITIES IN QATAR

00 Issued for General Use

A1 28th May 09 Issued for Review J Pilkington K Rose R Haddad

REV DATE DESCRIPTION WRITTEN BY CHECKED BY APPROVED BY

REVISION SIGNATURES



Occidental Petroleum of Qatar Ltd of 88

ELECTRICAL BASIS OF DESIGN Document No: 000000-4-XPS1-BD-0001-001

C:\Documents and Settings\pilkingj\Local Settings\Temporary Internet Files\OLK47\Electrical BoD 28th May.doc

CONTENTS

1. INTRODUCTION ........................................................................................................................... 4

1.0.

Scope and Purpose ..................................................................................................................... 5

1.1. Custodian .....................................................................................................................................5

2. ELECTRICAL SYSTEM DESIGN PHILOSOPHY ........................................................................6

2.0. General.......................................................................................................................................... 6

2.1. Protection against Explosion and Fire Hazards .......................................................................8

2.2. Environmental Conditions .......................................................................................................... 9

2.3. Power Supply Arrangements ................................................................................................... 10

2.4.

Protection, Power Management, Controls and Indications................................................... 13

2.5. ESD, DCS and General Control Interfaces .............................................................................. 16

2.6. Electrical Load Schedules and Load Forecasting .................................................................17

2.7. System Voltage, Frequency and Power Factor ......................................................................18

2.8. Voltages and Frequencies for Existing OPQL Installations ..................................................20

2.9. Electrical System Studies and Reviews .................................................................................. 22

2.10. Electrical Detailed Designs ....................................................................................................... 23

3.

EQUIPMENT SPECIFICATION AND SELECTION PHILOSOPHY ...........................................24

3.0. General........................................................................................................................................ 24

3.1. Generators..................................................................................................................................25

3.2. Neutral Earthing Resistors ....................................................................................................... 27

3.3. Switchgear ..................................................................................................................................28

3.4. Busbar Ducting .......................................................................................................................... 30

3.5. Power transformers ................................................................................................................... 30

3.6.

UPS Systems ..............................................................................................................................32

3.7. Electric Motors ...........................................................................................................................33

3.8. Cables, Wires and Supports ..................................................................................................... 34

3.9. Metering, Protection and Control equipment .........................................................................35

3.10. Power Management Systems ................................................................................................... 35

3.11. Packaged Equipment ................................................................................................................ 35

3.12. Variable Speed Drives and ESP’s ............................................................................................ 36

3.13.

HVAC Systems ...........................................................................................................................37






3.14. Navigational Aids....................................................................................................................... 37

3.15. Cathodic Protection Systems................................................................................................... 39

3.16.

Electric Process Heaters........................................................................................................... 39

3.17. Electric Motor Operated Valve Actuators ................................................................................ 39

3.18. Electrical Heat Tracing .............................................................................................................. 39

3.19. Lighting, Small Power, Bulks and Minor Equipment .............................................................39

3.20. Distribution Boards ................................................................................................................... 40

3.21. Subsea Cables and Umbil icals ................................................................................................. 40

4. EQUIPMENT INSTALLATION DESIGN REQUIREMENTS .......................................................41

4.0.

General........................................................................................................................................ 41

4.1. Cables, Routing Considerations and Accessories ................................................................41

4.2. Lighting and Small Power Installations................................................................................... 45

4.3. Earthing and Bonding ............................................................................................................... 48

4.4. Major and Packaged equipment items .................................................................................... 48

4.5. ESP’s and Variable Speed Drives ............................................................................................ 49

4.6. Switchrooms, Equipment Rooms, Battery and Plant Rooms ...............................................51

4.7.

HVAC Requirements.................................................................................................................. 53

4.8. Temporary installations ............................................................................................................ 55

5. DOCUMENTS AND DRAWINGS................................................................................................ 56

APPENDICES ............................................................................................................................................. 57

APPENDIX A – DEFINITION OF TERMS AND ABBREVIATIONS ..........................................................58

APPENDIX B – APPROVED CODES, STANDARDS AND SPECIFICATIONS ....................................... 62

APPENDIX C – ELECTRICAL BULK MATERIALS AND MINOR EQUIPMENT...................................... 65

APPENDIX D – EARTHING AND BONDING ............................................................................................ 70

APPENDIX E – RECOMMENDED ILLUMINATION LEVELS ...................................................................74

APPENDIX F – EXAMPLE FORMAT – PLANNED MAINTENANCE ROUTINE ...................................... 75

APPENDIX G - FACILITIES KEY RECORDS LIBRARY ..........................................................................78

APPENDIX H – ELECTRICAL CONSTRUCTION AND COMMISSIONING CHECKLISTS ..................... 79

APPENDIX J – IEC 60092-352 CURRENT CAPACITIES AND DEFINED INSTALLATIONS .................83






1. INTRODUCTION

Occidental Petroleum of Qatar Ltd (OPQL) operates the Idd El Shargi offshore Production Station PS1which is located 85 kilometres east of Doha. The station consists of a number of oil process, gas

process, utilities, water injection and accommodation jackets interconnected by bridges. Supplying the

production station with oil and gas from the North Dome (ISND) and South Dome (ISSD) fields are a

series of remote, unmanned wellhead platforms, interconnected to PS1 facilities by subsea pipelines.

Some (but not all) of these platforms have subsea power umbilicals. Oil and produced water is

transported to Halul Island via pipeline where the water and residual gas is separated from the oil prior to

fiscal metering then exported via oil tanker. The water depth at ISND and ISSD typically ranges between

28m and 33m.

Occidental also operate the Al-Morjan Permanent Production Facility and CALM loading buoy which

produce from the Al Rayyan oil field. This is a marginal field producing sour crude with a very low Gas Oil

ratio and very high water cut. The field is located approximately 84 km north/north east of Qatar

Peninsula in the Arabian Gulf. The water depth is typically 28m.

The location of the facilities are shown below.

DOHA

PS-1

PS-2

PS-3

Halul

Bunduq

Das Island

NAUTICAL MILES

50403020100

RAS LAFFAN

MESAIEED

DUKHAN

26' 00' N

25' 00' N

5 1 ' 0 0 ' E

5 3 ' 0 0 ' E

5 2 ' 0 0 ' E

N

ISND Field

ISSD Field

AL-MORJANField

OPQL MANAGED FACILITIES IN QATAR






1.0. Scope and Purpo se

This Basis of Design provides the framework for electrical design, engineering and selection of equipment

for Brownfield modifications to existing offshore facilities managed by Occidental Petroleum (Qatar) atISND, ISSD, Al Morjan and the existing onshore produced water handling facilities at Halul Island. This

document shall also be used to determine engineering philosophy and equipment specification/selection

for new offshore and onshore installations.

Installation design requirements differ significantly between onshore and offshore facilities. Where major

new onshore installations are being considered, reference shall be made to section 10 of QP Electrical

Engineering Philosophy ES.2.03.0001. This document details requirements for indoor and outdoor

onshore substations, transmission lines, underground cabling and segregation requirements, etc.

Engineering Contractors working on behalf of OPQL shall exercise due diligence and comply with the

requirements of this Basis of Design. This remains a live document and users should refer to the OPQL

Technical Authority (TA) concerning recent updates and amendments.

A uniform and consistent approach to electrical design and engineering of OPQL managed facilities shall

be adopted, noting that the installations all have different characteristics. Engineering shall be in

accordance with latest international standards and industrial installation practices, whether or not listed

within this Basis of Design. The most suitable electrical equipment shall be selected as fit for its intended

use considering both technical and economical issues. All safety requirements shall be complied with.

OPQL have a Process Risk Management (PRM) programme which identifies project specific reviews

(either discipline specific or multi-discipline as appropriate) for all changes to facilities. These reviews and

all other safety requirements shall be adhered to and incorporated into designs where appropriate.

This document should be read in conjunction with the relevant project “Statement of Requirement” or“Functional Design Specification” where these are available.

1.1. Custodian

The custodian of this document is the Electrical Technical Authority (TA) within OPQL Facilities

Engineering Department. Occidental Documents and Standards section maintain controlled copies of this

document and other Field Technical Information (FTI).

Requests for deviations from the application of technical standards requires authorisation from the OPQL

Technical Authority. Refer to OPQL Technical Authorities Manual, document 000000-8-XPS1-TD-0001-

001 for further details. All deviation requests, comments or recommendations should in the first instance

be directed to the Occidental Document controller.






2. ELECTRICAL SYSTEM DESIGN PHILOSOPHY

2.0. General

Compatibility with existing systems

Due regard shall be taken during engineering design and selection of equipment to ensure compatibility

between new and existing systems. Because of obsolescence issues and changing codes and

standards, it is recognised that full equipment compatibility is not always achievable (or indeed desirable).

Where any doubt exists, please refer to OPQL TA for guidance.

Standards, Codes and Regulations

The design and engineering of the electrical installation shall meet all the Statutory Requirements of the

National and Local Regulations currently in force in the State of Qatar. Legal requirements aredocumented in detail within QP Environmental Management Standard for Legal Requirements STD-ENV-

005. The requirements laid down by Qatar General Organisation for Standards and Metrology (QGOSM)

and *Ministry of Environment shall also be met.

*Formerly Supreme Council for the Environment and Natural Reserves (SCENR).

OPQL have entered into a Development and Production Sharing Agreement (DPSA) with QP to manage

a number of assets on their behalf within Qatar. OPQL are obliged to adopt good industrial practice when

managing these assets but application of QP codes and standards is not mandatory.

Occidental Oil and Gas Corporation (OOGC) have published a number of engineering guides which are

applicable to all subsidiaries operated and controlled by OOGC (this includes OPQL). The general

introductory guide (EG-300) defines these as intended for onshore oil and gas processing facilities only

and makes provision for the use of International, host country or locally mandated regulations where

these meet (or exceed) the OOGC guides. Hence, these guides will not be applied to OPQL (mainly

offshore) managed facilities.

The OPQL managed facilities have to a large extent been engineered based upon British Standards

Institute publications (BSI) and those published by the International Electro technical Commission (IEC).

These publications, together with OPQL and QP codes and standards shall form the basis of OPQL

adoption of good industrial practice.

OPQL and QP have published a large number of specifications, standards, codes and regulations, some

of which are generic and others prepared for specific project purposes. Not all of these are maintaineddocuments and conflicts do exist. Where significant conflicts are identified, these should be referred to

OPQL TA for advice. An abbreviated list of the most relevant documents prepared by OPQL and QP is

given in Appendix B and referenced throughout this Basis of Design. This document and the standards

referred to shall be used for the specification and selection of equipment and materials for use on facilities

managed by OPQL on behalf of QP. The substitution of other standards requires prior approval from

OPQL TA.

Engineering design activities and equipment offered should be of a good quality, be fit for its intended use

and designed/manufactured to recognised industry standards without “gold plating”. If engineering

contractors or equipment suppliers considers that any specification requirements result in avoidable

additional cost then this shall be brought to the attention of OPQL.






In the event of any conflict between this Basis of Design and other Specifications and Data Sheets or with

any of the applicable Codes and Regulations and as a general principle, the most stringent shall apply. In

case of conflict, OPQL shall be notified in writing before proceeding with any work. OPQL’s decision shall

be final and binding. The general order of precedence shall be as follows:

1) Statutory Requirements

2) This Basis of Design

3) OPQL Data Sheets, Standards and Specifications

4) Qatar Petroleum Data Sheets, Standards and Specifications

6) International Codes and Standards

The SI system of units shall be used. All documentation shall use the English language. Electrical

symbols shall conform to QP Engineering Standard for Draughting, document number ES.D.10. Where

symbols are not given in ES.D.10, those given in IEC 60617 shall be used.

Operational Safety, Security of Supply and Reliability

The design of the electrical installation shall be based on the provision of a safe and reliable supply of

electricity at all times. Safe conditions shall be ensured under all operating conditions, including those

associated with start-up and shutdown of plant and equipment, and throughout the intervening shutdown

periods.

The design of electrical systems and equipment shall ensure that all operating and maintenance activities

can be performed safely and conveniently. Essential equipment and supplies shall be backed up to allow

maintenance without disturbance to process operations. Distribution system design and protection

systems shall be engineered so that the minimum amount of equipment is disconnected following an

electrical fault.

The design of the electrical installation shall ensure that access is provided for all operational and

maintenance purposes. Adequate isolation facilities shall be provided, compatible with OPQL Permit to

Work systems. More details concerning this is provided within OPQL Procedure PRD 500, Electrical

Safety Guidelines.

The requirements of OPQL Process Risk Management Programme shall be complied with. Actions

arising from these risk reviews shall be incorporated into engineering designs in an auditable manner.

Quality Assurance and Control

The contractors, consultants and manufacturers of equipment shall have a quality management system

which conforms to the requirements of IS0 9000, IS0 9001 and IS0 9004.

Certificates, Declarations and Test Reports

For all major electrical equipment like generators, motors, VSD’s, switchgear, transformers and UPS

systems, Type Test Reports of the equipment shall be provided by manufacturers at the tendering stage

of an enquiry.

In addition to other Type Tests, short-circuit test reports especially for switchgear, transformers,

generators, bus-bar ducting and motors shall essentially be submitted.

Certificates or declarations in relation to the application of equipment in hazardous areas shall be

provided by manufacturers. All equipment and devices sourced from European manufacturers and

installed in hazardous areas shall be manufactured as per ATEX directives. Alternative certification






For installations having presence of flammable dust, area classification and selection of electrical

equipment shall be as per IEC 61241. For the construction and installation of electrical equipment in

hazardous area, all relevant parts of IEC 60079 shall be complied with. Following shall be considered for

proper selection of electrical equipment for use in hazardous area:

Electrical distribution equipment shall normally be installed in non hazardous areas. Where it is

impractical to comply with this requirement, hazardous area equipment may be considered subject to

approval of OPQL TA.

Electrical sub-stations should normally always be located in non-hazardous areas.

2.2 . Env i ronm enta l Cond i t io ns

Engineering designs and equipment shall be in general comply with the requirements of the latest edition

of QP Standard Offshore Environmental Conditions; document number EFS.00.08.03.

The climatic conditions associated with the Occidental managed facilities are those of a corrosive marine

environment with high humidity and a highly saliferous atmosphere. High levels of abrasive dust may be

present periodically. The design wind speed shall be taken as 45m/s and the average barometric

pressure ranges between 995 and 1020 mbar. The annual rainfall ranges between 13mm and 175mm.

Lightning and thunderstorms occur but are relatively infrequent. Refer to EFS.00.08.03 for more detailed

information concerning wind and weather conditions.

Ultra-violet radiation levels are high. All plastics, including glass reinforced plastics exposed to direct

sunlight shall be ultra-violet resistant.

TEMPERATURES AND HUMIDITY

PARAMETER SUMMER WINTER

Recorded maximum shade temperature 48oC 38

oC

Recorded minimum shade temperature 21oC 4

oC

Design maximum air temperature *50oC

Average daily maximum relative humidity 90% 95%

Average daily minimum relative humidity 50% 50%

Maximum temperature of surfaces exposed to sun

(Black bulb temperature)84

oC

Sea surface temperature 35oC 15

oC

Sea bed temperature 25oC 15

oC

*Temperature excursions above 45oC are relatively infrequent and short duration and in most instances,

an ambient temperature limit of 45oC will be acceptable for equipment specification and cable sizing

purposes. If in doubt, please refer to OPQL TA for guidance.






The ambient air temperatures for enclosed modules, equipment rooms, switchgear rooms and control

rooms shall generally be within defined conditions as dictated by the HVAC system, typically 25oC. To

satisfy conditions that may occur when HVAC is inoperative, the internal air temperature shall be

considered as a maximum of 45o

C (under extreme, infrequent conditions). Engineering contractors andmanufacturers shall take this into account when calculating and quoting de-rating factors for main power

components of equipment.

Allowance shall be made for the entry of dust, salt and sulphur contaminated air. When the HVAC is out

of service, humidity levels of 95% can be experienced and due allowance shall be made for this.

Equipment installed on platforms shall be designed for the following accelerations due to earthquakes:

• Horizontal acceleration 0.2g

• Vertical acceleration 0.15g up or down

Equipment installed on platforms shall be designed for the following forces due to barge motion during thesea voyage from fabrication yard to offshore site. These forces shall be considered to act coincidentally

with the equipment weight.

• Horizontal force 0.7W (Pitch or Roll) + 0.2g Vertical

2.3 . Power Supp ly Ar rangements

Existing installations

Power supply arrangements for existing installations are largely determined by the existing platform

facilities. Refer to section 2.8 for details of available voltages and frequencies on OPQL managed

facilities. The following alternatives for the electrical supply shall be considered when designing theelectrical supply and distribution systems for additions to existing installations:

• Utilization of existing power generation and distribution systems

• Captive power generation (i.e. own generation)

• Power provided from an adjacent OPQL facility via subsea cable.

• *Power provided by third party facilities

• Alternative energy sources (for example battery systems charged by Photo-voltaic (PV) solar

arrays, wind turbines, intermittent running gensets etc.) can be considered for low power

(instrumentation and radiotelemetry) applications on remote unmanned platforms.

*There are security of supply, economic and contractual issues that require to be considered and finalized

before power from third parties can be accepted. Please refer to OPQL TA for guidance on these

matters.

New installations

Subject to compatibility with existing installations, voltage levels shall be selected from IEC 60038. The

nominal voltage supply recommended in IEC 60038 is 400/230V 3 phase and neutral on 50Hz systems.

For new plants, the capacity of the electrical distribution system shall be capable of supplying

continuously 125% of the peak load. While sizing equipment like generators and transformers, direct on

line starting and auto-reacceleration of motors shall be duly considered. Future plant load, if any, shall be

duly considered in the peak load calculations. This 25% spare capacity is kept to cater for the possibility






of future de-bottlenecking of the plant and to accommodate changes taking place during project design

that may involve minor adjustments in electrical loads. This factor of 25% may get reduced to 10% when

the plant is ready to start.

The number of power supply generator or power transformer units to be installed and their individual

ratings depend on many factors, e.g. maintenance requirements, economic size, future load development

pattern, unit reliability etc. Sufficient stand-by capacity shall be incorporated to fulfil the requirement of

the peak load continuously, even if the largest supply unit trips or is out of service for maintenance

purposes. The provision of stand-by capacity shall be considered in relation to safety, reliability and the

continuity of plant operation.

For plants having only captive generating units, the number of units n+2 or n+1 (where n is the number of

generating sets required to supply the peak load) shall be decided by the nature of process and

acceptance of load shedding scheme for non-essential loads. Sufficient spare capacity shall be available

to avoid load shedding following loss of the largest generator or supply source.

The availability of further stand-by supply capacity to cater for unit failures during maintenance or repair

periods shall be provided where the aggregate maintenance or repair time warrants this. Where no such

capacity is provided, nor it is practically possible to provide (especially for an existing plant), then

automatic load shedding schemes shall be implemented.

The maximum rating of power transformers shall be decided such that the rated current of their low

voltage winding does not exceed 2000 A when feeding HV switchboard and 2500A when feeding LV

switchboard. Higher ratings shall only be considered in case of significant cost saving. Please refer to

OPQL TA for guidance and approval as required.

Distribution Philosophy

The main sources and feeders of power shall be duplicated in such a manner that if one of them is tripped

or is out of service, the remaining units can take care of the total power. New plants should be designed

with sufficient spare capacity in the captive generation (n-1) to render load shedding unnecessary under

normal operation of the plant.

Consideration shall be given to providing a secondary selective interlocking system to automatically

reinstate power following loss of a single feeder. Details are provided within QP Engineering Standard for

Secondary Selective System ES.2.14.0060.

Each distribution system should have reliability at least comparable with its primary supply system and

shall incorporate sufficient standby capacity to enable maintenance work, tests and inspection checks to

be carried out without operational disturbance.

Single Line Diagrams

The conceptual design and philosophy of the electrical distribution system shall be represented by means

of a Single Line Diagram. This diagram may be a new document or a modification of an existing

document. The following information shall be shown on the Single Line Diagram:

• All sources of electric power

• The main supply voltage and distribution system interconnections at each voltage level

• System capacities, autonomies, frequencies, equipment ratings (including fault ratings), and

impedances, winding configuration and earthing arrangements

• Vector diagrams for all voltage levels






• Relevant information that basically describes the design and operating philosophy to be adopted

for the system, e.g. arrangement of main and stand-by circuits, normal switch positions, switch

interlocking and circuit changeover facilities, synchronising facilities, power factor correction

facilities, anticipated future loads or circuit extensions, etc.

• Location of earth switches, CTs, VTs and measuring instruments

• Interfaces with remote SCADA, DCS, PMS, substation controls etc.

• Details of all protective devices

• Cable type, size and tag numbers

• HV motor kW ratings

For large installations, the Single Line Diagram can be sub-divided into several Single Line Diagrams so

that all aspects are shown more clearly and easily. Nominal system voltage(s), frequency and the

positive phase sequence shall be indicated on the Single Line Diagram. The phase sequence shall be

specified in alphabetical order L1, L2, L3 or U, V, W, each phase reaching its maximum in time sequence

in that order.

Load Shedding

Load shedding shall be based upon the high speed tripping of the lowest priority loads. Various loads or

groups of loads shall be selected for load shedding, ranked and placed in the tripping sequence. The

load shedding system shall pre-calculate the minimum number of loads to bring the system back into

balance in the event of supply loss. On receipt of a load shed signal these predetermined loads will be

tripped. The priority sequence and choice of loads for shedding shall be determined based upon

ensuring system stability with minimum operational disturbance.

Short Circuit Capacities

All equipment shall be capable of withstanding the effects of short circuit currents (initial symmetrical short

circuit current and peak short circuit current) and consequential voltage arising in the event of equipment

failure or equipment faults. Each short circuit interrupting device shall be designed to have rated breaking

capacity equal to or higher than the maximum value of short circuit current calculated at its location.

For calculation of maximum value of short circuit ratings including the short circuit making and breaking

capacity of circuit breakers, parallel operation of all power supplies and contributions from motors shall be

duly considered.

For power intake switchboards, close co-ordination will be required with the third party power providerand due consideration shall be given to the expected future planned increase in short circuit level.

The short circuit rating of generator switchgear shall be calculated taking into consideration the maximum

number of generators simultaneously in operation including future expansions. All switchgear and bus-

bar ducting shall withstand the maximum fault current for a minimum period of one second. Sizing of high

voltage cables shall be based on the short circuit withstand capacity for a duration dictated by the

protection system.

Neutral Earthing

For HV systems with voltage not exceeding 33 kV, the neutrals of following shall be earthed through a

current limiting Neutral Earthing Resistor (NER) or other approved fault limiting device:

• Generators directly connected to HV switchboards






• Generator transformers

• Incoming transformer feeders from third party power providers

The rating of each NER shall be such as to limit the earth fault current supplied by the equipment to whichit is connected to a value as low as practical and which can be reliably detected by earth fault relays in

the circuit. Generally the earth fault current shall not exceed 50% of transformer or generator full load

current.

Where generators are connected in parallel to the same switchboard and each is earthed through its own

NER, then each NER shall be rated to allow the circulation of zero sequence harmonic currents to flow

continuously. If the circulating current is such as to exceed the thermal rating of the NER, then the

generators shall be earthed via one NER only. Each generator shall then be provided with a suitable

switching device to facilitate connection of any generator to the single NER.

LV electrical system neutrals at each source of supply shall be solidly earthed by means of dedicated

earth electrodes, which have a direct, low impedance connection to the installation main earth grid. The

system of earthing shall be designated as 'TN-S', as defined in IEC 60364, unless otherwise specified.

For fixed LV equipment, the earth loop impedance shall be low enough to cause circuit disconnection in

less than one second (as determined by equipment fault limits), when a bolted fault of negligible

impedance is applied. Refer also to Appendix D.

AC UPS systems shall have their neutrals solidly earthed. DC UPS systems for electrical loads and

critical lighting shall normally be unearthed. Earthing of DC UPS systems (for electrical, telecom, fire

alarm and plant communication systems) shall take into account recommendations of the respective

equipment manufacturer.

2.4 . Pro tec t ion , Power Management , Cont ro l s and Ind ica t ions

Electrical Protection System

The electrical system shall be equipped with reliable automatic protection. QP Engineering Standards for

HV Switchgear and Control gear for indoors ES.2.14.0010 and LV Switchgear and Control gear

ES.2.14.0015 give details of the selection and specification of switching and protective devices, control

circuits and associated auxiliary equipment.

The type and characteristics of protective devices shall be selected according to the application and shall

be compatible with those of existing system. However, for new installations microprocessor based

numerical protection system in combination with a Power Management System shall be considered.Protective relays shall be solid state multi-function. Protection should use 'industry standard'

communications protocols compatible with relevant systems (for direct interface with DCS, power

management systems etc.)

The automatic protective systems shall be designed to achieve selective isolation of faulted equipment

within a time corresponding to the short-circuit current withstand capability of equipment, system stable

operating limits and the maximum fault clearance times.

Adequate and selective phase short-circuit and earth fault protection shall be provided. Due regard shall

be given to the magnitude of short-circuit currents and method of system earthing. Limited duration over-

currents arising from single or group motor starting and reacceleration shall be permitted. Automatic

control systems such as load transfer, motor restarting arrangements and protective systems to initiate

load shedding, may be required for a particular plant.






A protection diagram in the form of a Single Line Diagram shall be prepared for the complete electricity

supply and distribution system. The drawing shall indicate the type and location of all protective devices

and associated CTs and VTs that are to be provided. Based on this drawing, an electrical protection

report shall be prepared which shall demonstrate the adequacy of all protective systems in fulfilling theabove requirements. The protection report shall include at least a description of the system and of the

system operating modes on which the settings have been based, together with relevant short circuit

current calculations or computations for specified minimum and maximum generation or supply

conditions, single line diagrams for each part of the system, tabulated settings of the individual devices

and co-ordinated characteristics of the protection devices and fuses, etc., plotted in graphical form.

Protective relay settings shall be based on a study of the fault conditions for which the protective system

has been designed and incorporated. Protective relay systems shall be selective and the settings shall

be co-ordinated so that back-up protection is provided in the event of protective system or switching

device failure. The minimum generation or supply capacity conditions shall be at least representative of

those that arise during normal operation of the process units, production facilities and their utilities.

Where required, the dynamic performance of the electrical system shall be analysed to verify the

adequacy of the protection system provided, by ensuring successful recovery of the electrical system to a

stable operating state following the clearance of a short circuit. The study shall be repeated for the

application of a short circuit at various critical locations in the power system. In particular, systems

incorporating on-site generation as the main means of power supply, shall be studied to establish the

extent to which re-energisation of essential service loads may be applied. The protection of the

interconnections with third party power providers require to be mutually agreed.

The protection relay settings shall be self-contained within the relay so that they can only be changed at

the relay, and not by remote means. For intelligent relays, access to the settings shall be via the software

and password protected or by a similar secure method.

Power Management System

A dedicated Power Management System (PMS) for the electrical generation and distribution system shall

be considered where centralised supervision, control and metering is required. This system shall comply

with the requirements of QP Engineering Standard for Power Management System ES.2.14.0065. The

requirements of OPQL Specification for Power Management Systems, document No. 403086-4-PS1E-

SP-0002-001 shall also be taken into consideration.

For new projects involving power generation, consideration shall be given to installation of a Power

Management System (PMS). For upgrade projects, the requirement of PMS shall be based on the

operational requirements, operator task analysis and an economic evaluation.

PMS Basic Requirements and DCS Interfacing

The PMS shall be a continuously on-line computer-based system using high integrity self monitoring

PLC’s. For new installations, it shall not be an integral part of the overall DCS network system and the

operation of the power system shall be kept independent of other DCS type of operations. An important

function of the PMS will be to ensure system stability in event of disturbances. This will include a high

speed load shedding needed when one or more generators or system feeder’s trip. This essential feature

will require the PMS to be constantly monitoring the power generation and distribution network status, to

be making complex real time calculations based upon dynamic power information, and to be in a state of

readiness to load shed within a few milli-seconds of receiving a “load shed” initiating event.






The PMS should be connected to the overall DCS system simply for the purpose of 'delivering'

information to the DCS network for the purposes of event recording, trending, reporting and the like. The

systems architecture and functional design specification shall be established at an early stage of a new

project in conjunction with instrumentation group. This will enable the PMS to function as required, withthe maximum availability, when the connection to the DCS is out of service.

PMS Management Funct ions

The main PMS functions that should be considered are:

• VDU display of main equipment in single-line format, at a suitably located control point

• Display of load flows, voltage profiles, frequencies

• Alerting operators when n+1 power margin is not satisfied

• Operational status of equipment

• Load shedding

• Inhibiting the start of large motors on load mismatch

• Protecting the ability of fire pumps etc., to start even on load mismatch

• Load sharing between generators and third party feeders

• Synchronising of generators

• Monitoring and alarming performance

• Fault level surveillance in special cases

• Intelligent interlocking for special cases

Other details like configuration, inputs, outputs, displays, indications and alarms shall be as

detailed out in QP Engineering Standard for Power Management System ES.2.14.0065.

Control, Metering, Alarms and Indications

Adequate controls, metering, alarms and indications for checking and monitoring of the power system, as

required for proper control and operation of the electrical installation shall be provided. Metering shall be

provided to keep a record of power consumption and measurement of current, voltage, power, frequency,

power factor etc. Where third party supplies are provided to (or from) OPQL, consumption metering shall

be revenue class. Maximum demand indicators shall be provided for third party supplies with contractualtariff restrictions.

QP Engineering Standards for HV Switchgear and Control-gear for indoors ES.2.14.0010 and LV

Switchgear and Control-gear ES.2.14.0015 give full details of requirements for each type of incomer and

outgoing feeder. Equipment specific requirements are also covered in QP Engineering Standards for HV

Gas Turbine Driven Synchronous Generators ES.2.14.0001, Diesel Engine Driven Generators

ES.2.14.0002, HV Induction and Synchronous Motors ES.2.14.0030, Electric Motor Operated Valve

Actuators ES.2.14.0036, AC UPS Systems ES.2.14.0040 and DC UPS Systems ES.2.14.0044.

Grid intake circuits which are required to operate in parallel with captive generators shall be provided with

synchronising facilities, check synchronising relay and dead-bus override. These controls shall be

located where control of the frequency and voltage of the generators can be exercised. Each motor






circuit shall be provided with a remote ammeter and provision of power supply for motor anti-

condensation heater (for all motors above 30kW).

Switching counters shall be provided on all HV motor and transformer feeders. Running hour meters shall

be provided for generators and HV motors.

Classifi cation of Electrical Loads

Electrical loads shall be classified as performing a service, which is of the following types:

• Vital (i.e. critical)

• Essential (i.e. emergency)

• Non-essential (i.e. normal)

Refer also to QP-PHL-S-001 Corporate Philosophy for Fire and safety, section 14; Emergency Power

Supply System.

Vital Service

Vital service is a service which, when failing in operation or when failing if called upon, can cause an

unsafe condition of the installation, jeopardise life or cause major damage to the installation. This applies

to life support systems on offshore platforms, emergency and escape lighting, DCS, ESD etc. Depending

on the service conditions, the electrical supply to the vital service may have to be non-interruptible. Since

the faultless functioning of equipment cannot be guaranteed, duplication of sources of power supply and

redundancy of equipment shall be provided. Vital services are normally provided by dual redundant

battery backed power supply systems, or by self contained battery/inverter packs for plant emergency

lighting.

Essential Service

Essential service is a service which, when failing in operation or when failing if called upon, can affect the

continuity of operation, the quality or the quantity of product. Therefore the economics of partial or

complete duplication of the energy source, of the lines of supply or of the equipment or the introduction of

automatic restarting facilities or of changeover facilities or provision of standby energy source shall be

evaluated in relation to the consequences of service interruptions mentioned above. One example is a

power supply to process equipment by means of a duplicate supply system with a changeover facility.

Non-essential Service

Non-essential service is a service that is neither vital nor essential and therefore does not require any

special measures for safeguarding it. An example of this is normal lighting or non critical domestic

installations, etc.

2.5. ESD, DCS and Genera l Contr o l In ter f aces

In general, interfaces between electrical and instrument systems should not introduce voltage levels into

equipment not already present. Unless otherwise advised, interface signals to DCS and ESD panels

shall be at 24V DC. Where required, interposing relay panels shall be installed to segregate equipment

voltage levels.

Interfaces between electrical and control systems (i.e. DCS) should be selected to ensure

communications protocol compatibility with minimal (ideally no) intermediate converters. A serial link






interface is preferred when large numbers of signals are involved. Lesser signal requirements (grouped

common alarms etc.) shall be hard wired. All safety critical signals (ESD etc.) shall be hard wired.

Interconnected PLC based control systems with fast response requirements (for example load shedding),

functional logic and initiating devices require special consideration and may require event prioritization

and/or fiber optic/direct wired connections. Refer to OPQL Electrical and Instrument TA’s for additional

guidance if required.

2.6 . E lec t r i ca l Load Schedu les and Load Forecas t in g

Summations and Diversity Factors

A schedule of electrical loads shall be prepared as early in a project as possible in an approved format

(examples can be made available by the OPQL TA). The Electrical Load Schedule will form the basis for

confirming the necessary electrical distribution system capacity and what upgrades (if any) are required.

The following shall be included in the Electrical Load Schedule:

• The installed electrical loads

• Category of load i.e. continuous (all loads required continuously for normal operation and running

all the time), intermittent (all loads required for intermittent operation and running occasionally) or

standby (all loads required in emergencies only).

• Rated active power in kW (shaft output), rated power factor, rated current, rated efficiency and

load factor.

• Absorbed active power in kW

• Reactive power in kvar

The continuous (Sum C), intermittent (Sum I) and standby (Sum S) loads shall be summated separately

in a manner that does not introduce kW/KVAr summation errors. A diversity factor shall be applied to

each of these summations so that the Total Plant Running Load (TPRL) and the Total Plant Peak Load

(TPPL) can be calculated.

The recommended diversity factors are 1.0 for (Sum C), 0.3 for (Sum I) and 0.1 for (Sum S). Adequate

care needs to be given to the requirement that 0.3 x (Sum I) shall not be less than the largest single

intermittent load. For non-process loads like offices, workshops lighting etc., a typical diversity factor of

0.9 shall be applied to (Sum C) of such loads.

The TPRL, shall be the sum of 1.0 x (Sum C) and 0.3 x (Sum I). The TPPL shall be the sum of 1.0 x (SumC), 0.3 x (Sum I) and 0.1 x (Sum S).

The diversity factor may vary and there will be instances where engineering judgement has to be applied.

Where necessary, the OPQL TA shall be consulted for guidance. The load schedule is critical to allow

accurate estimating of equipment and shall be finalised as an early stage of the project. For extension of

existing plants, the TPRL, and TPPL shall be checked against the actual measured values of the facility.

All loads to be automatically restarted after a voltage dip shall be clearly identified. Also, all loads to be

shed as part of load shedding scheme shall be clearly identified. The Electrical Load Schedule shall be

updated regularly throughout the design stage of the project.






Sub-division of Electrical Load Schedule

A separate schedule shall be prepared for each HV and LV switchboard. Each separate schedule will

therefore be a sub-division of the complete Electrical Load Schedule. Each subdivision shall clearly show

the following information:

• Summations of the load fed from the particular switchboard, excluding feeds to and received from

other switchboards

• Active and reactive power fed individually to other switchboards, including losses in feeder

transformer if used

• Total active and reactive power received from the source, e.g. up-stream switchboard, generator,

transformer intake.

Load forecasting and power profiling

Power profile load forecasts are used for scenario planning and to estimate load growth over the

operating life of an asset. Where required, these shall be provided in an approved format (examples can

be made available by the OPQL TA).

2.7. System Vol tage, Frequency and Power Facto r

Selection of vo ltage and frequency

The various voltages to be adopted shall be decided based on the following factors:

• Compatibility with voltage levels of existing installations

• Size and location of loads

• Future margin and expansions

• Short circuit levels

• Availability of switchgear for continuous and short circuit ratings

• Keeping the number of different voltage levels to a minimum

• Economic considerations

The frequency for all installations shall be 50 Hz unless limited by source of supply constraints (as at Al-

Morjan).

Deviations in Supply Voltage and Frequency

The following parameters are to be applied to new installations and can be used (in the absence of site

specific information) as a guide to system disturbances that can be expected on power installations of

existing installations.

During normal system operation, the voltage at consumer terminals shall not deviate from the rated

equipment voltage by more than +/-6% and the frequency shall not deviate from the rated frequency by

more than +/-2% under steady-state conditions. The combined voltage and frequency deviations shall lie

within Zone-A as described in IEC 60034. All loads shall be balanced such that the negative phase

sequence components of voltage and current, at any point in the system, shall not exceed the values

quoted in IEC 60034.






During starting or re-acceleration of a motor, either individually or in a reacceleration group, the transient

voltage dip at the motor terminals shall under no circumstances exceed 20% from rated voltage when

started direct on line under the worst operating scenario (i.e. the largest motor started against the

minimum fault level) - this is an absolute operating limit. When sizing cables for new and existinginstallations, locked rotor voltage drops shall be kept within a 15% limit. Transient voltage variations

occurring at switchgear bus bars during starting or re-acceleration of a motor or group of motors shall be

such as to maintain a minimum of 90% voltage on switchgear bus-bars for HV motors and 92.5% for LV

motors. Voltage depressions resulting in consumer terminal voltages down to 80% of rated voltage shall

not affect plant operations.

In the absence of any other consideration, under normal service conditions the voltage at the terminals of

equipment shall be greater than the lower limit corresponding to the said equipment.

When sizing cables and calculating voltage drops, a maximum steady state aggregate voltage drop for

feeder and motor and final sub circuits of 6% shall be considered (this being based upon a 2% limit for

feeders and a further 4% for final sub circuit). Refer to section 4.1 for cable sizing design basis.

The maximum voltage drop in UPS powered systems requires special consideration and shall take into

account voltage decline during battery discharge conditions together with voltage tolerances of connected

instrumentation. These shall be assessed on a case by case basis. In the absence of more detailed

information, the following tolerances are recommended:

• DC UPS outgoing feeders (for electrical controls): 5%

• DC UPS instrumentation outgoing feeders: 2%

• AC UPS instrumentation outgoing feeders: 5%

In the absence of approved project specific cable sizing documents and software, engineering contractors

shall use document number YPS1-4-CA-6921-001 Phase 3 Water Injection LV cable sizing tables. This

document is available from OPQL DCC on request.

Deviations and Variations in Supply Waveform

All equipment shall be suitable to operate satisfactorily with a total harmonic voltage distortion of 5% in

the supply voltage. Electrical loads having non-linear characteristics, such as to produce voltage and

current waveform distortion of a magnitude detrimental to the lifetime or performance of electrical

equipment shall not be utilised unless appropriate measures are taken to render harmless the effect of

such distortions e.g. by filtering or phase displacement, etc.

For installations having submarine cables used to transmit power to or from offshore platforms, studiesmay be required to determine the possibility of resonances occurring especially at low order harmonics

leading to over voltages and over currents. Means shall be provided to mitigate the problem of

resonance and to avoid the voltage distortion at the load or the supply. This can take the form of either

active or passive harmonic suppression. Based on the study, necessary protective measures shall be

adopted. However, these will be project specific. Equipment having special requirements with respect to

variation in voltage level and waveform shall be provided with a power supply that is adequately stabilised

or filtered.

System Power Factor

The overall system power factor, inclusive of reactive power losses in transformers and other distribution

system equipment, for new installations should ideally be no less than 0.9 lagging at rated load. The

requirements for power factor correction shall be decided at an early stage of the project. Static






Capacitor Banks (HV and or LV) shall be provided to improve the power factor. Automatic control of

Capacitor Banks shall be provided where these are provided for a group of motors/ loads.

The measured power factor for OPQL managed facilities is typically in the range of 0.8 - 0.85 lagging

(PS1 facilities are 0.85).

2.8 . Vo l tages and Frequenc ies fo r Ex is t ing OPQL Ins ta l la t ions

General

The primary system characteristics are summarised below, facility by facility. It has not been possible to

list all of the voltage levels for all of the remote facilities but this information is available on key drawings

available from OPQL Documents and Standards section.

Idd El Shargi - PS1 Product ion Station - (ISND)

There are two main power plants on PS1. The PS1E power plant comprises four x *2.36MW RGT

Gensets generating and supplying power at 3300v, 3ph, 50Hz to a main dual section HV switchboard

SB4141. The generators neutrals are individually earthed through NER’s. The HV voltage is transformed

to 415v, 3ph, 50Hz via two x 1600kVA transformers which supply a low voltage switchboard SB4102.

There is one diesel genset on PS1G which provides 415v, 3ph, 50Hz to the emergency switchboard

SB4103 and two further 415v, 3ph, 50Hz diesel gensets which provide power for platform black-starting.

There are also 415v, 3ph sub-distribution switchboards on PS1R, PS1W, PS1G and PS1Q. Lighting and

small power distribution is at 415v 3ph and 240v, 1ph.

The PS1K power plant comprises 3 x *12.82MW Solar Titan GT gensets generating and supplying powerat 6600v, 3 ph, 50Hz to a main dual section HV switchboard SB3102. Neutral earthing is provided by 2 x

earthing transformers connected to sections A and B of SB3102. The HV voltage is transformed to 415v,

3ph, 50Hz via 2 x 1600kVA transformers which supply the PS1K low voltage switchboard SB3103. There

are 2 x 5/7MVA interconnectors which provide 2 way power exchange between SB3102 and SB4141.

PS1K has no emergency switchboard and is also dependent upon PS1E power plant for black starting.

Lighting and small power distribution is at 415v 3ph and 240v 1ph. Further information is available within

PS1K Electrical Basis of Design, document 402160-4-PS1K-BD-6015-001.

There are a number of battery backed UPS systems which provide vital and emergency power at 240v

ac, 50Hz, 110v DC and 24v DC (typically 60 minutes autonomy for PS1E and 90 minutes for selected K

loads). There are also other battery systems providing battery backed power to navigational aids, turbine

control systems and engine starting batteries.

There are also a large number of remote, unmanned wellhead platforms. Some (but not all) of these

wellheads have subsea power umbilicals from PS1,variously powered at 6600v, 3300v and 415v. The

remainder are powered at 24v DC via a mixture of photovoltaic solar arrays and wind turbines with back-

up batteries.

*Note: - The available output power from the gensets is less than nameplate ratings, for example PS1ERGT’s cannot reliably deliver more than 2MW and PS1K Solars are normally limited to 9.6MW or less.






This is based upon site ratings and operator experience over several years. Refer to OPQL TA for further

information if required.

Idd El Shargi – IS04 and IS34 Remote Facilities - (ISSD)

The two ISSD platforms do not have their own independent power plant. On PS1 voltage is transformed

from 3300v to 6600v via a 3MVA transformer located on PS1R. PS1 and IS04 are linked via a 22km 3c

300mm subsea cable. The incoming 6600v 3ph, 50Hz supply on IS04 powers switchboard 71-SB12731.

IS34 is powered from IS04 via a 2.2kM 3c 95mm subsea cable from switchboard 71-SB12731. The

6600v supply on each of the two platforms is transformed to 480v via a 2.4MVA transformer on each

platform. This is a dual secondary transformer used to supply two 480V switchboards (one star, one

delta) which in turn supply a number of ESP’s. HVAC is powered from the star switchboard at 480v, 3ph,

50Hz. Lighting and small power is provided at 480v, 3ph, 50Hz and 277v, 1ph, 50Hz. There is a 15kVA

480/240v ac transformer which provides a limited amount of power at 240v for equipment unsuitable for

277v supply.

Halul Island – Produced Water Handling Facili ties (PWHF)

The OPQL PWHF at Halul does not have its own independent power plant. It is supplied with power via

two x 33kV feeders from an adjacent substation. The incoming 33kV voltage is transformed to 11kV by

two x 15MVA transformers which supply an 11kV switchboard SB5170. The transformer neutrals are

individually earthed. This is transformed to 400v, 3ph, 50Hz via two x 1600kVA transformers which

supply a low voltage switchboard SB5171. This switchboard has an auto transfer system which closes

the bus section on loss of one of the incoming feeders. There is one 400v, 3ph, 50Hz diesel genset

which provides limited backup power to SB5171. Loads are selectively shed from SB5171 following an

interruption of the primary power supply. Lighting and small power distribution is at 400v, 3ph and 230v,

1ph.

The PWHF substation was installed and is operated by OPQL, however the 11kV switchgear also

supplies power to a number of QP operated assets on HALUL island.

There are a number of battery backed UPS systems which provide vital and emergency power at 110v

ac, 50Hz, 110v DC and 24v DC (typically 60 minutes autonomy). There is also a 24v DC UPS providingpower to remote telemetry units (RTU’s). This is supplied from QP combined industrial building 415V,

3ph switchboard.

Further information is available within The PWHF Electrical Philosophy, document 400060-4-HALU-6593.

Al Rayyan - Al-Morjan Permanent Product ion Facil ity and CALM loading Buoy

The OPQL Al-Morjan facility does not have its own independent power plant. On NFA, voltage is

transformed from 6600v to 33kV via a 15MVA transformer fitted with automatic tap changers to provide

voltage regulation. NFA and Al-Morjan are linked via a 41km 3c 185mm subsea cable. The incoming

33kV, 3ph, 60Hz supply to Al-Morjan powers a main 33kV switchboard SB945B.






The 33kV voltage is individually transformed and distributed to four x 480v, 3ph, Electrical Submersible

Pump (ESP) switchboards. Voltage is transformed to 440v, 3ph, 60Hz, supplying process and utilities

switchboards. There are a number of standby and emergency diesel gensets which provide limited

backup power at 440v, 3ph, 60Hz when the primary supply from NFA is unavailable.

HVAC distribution is supplied at 440v, 3ph, 60Hz. Lighting and small power distribution is supplied at

380v, 3ph, 60Hz and 220v 1ph.

There are a number of battery backed UPS systems which provide vital and emergency power at 220v,

60Hz ac (instruments), 48v DC (telecoms), 24v DC (navaids). The autonomy period is 60 minutes.

Further information is available within the Electrical Design Basis included within section 8 of the Al-

Morjan Basis of Design.

2.9. E lectr i ca l System Studi es and Reviews

Where major modifications or additions to platform facilities are contemplated, then concept studies,

usually single discipline (but often part of a larger multi-discipline concept development) shall be

competed. These are typically initiated with a project Statement of Requirement (SoR), project objective

statement, etc. and scope of study agreed with OPQL TA. QP Engineering Standard for Power System

Studies ES.2.14.0095 can be used as a guide when developing the study scope of work. These will

typically evaluate several study options and investigate/eliminate those which are non viable.

The Power System Studies and Protection studies shall be performed in support of the design and

procurement of equipment with correct specifications. These studies may comprise of the following

depending on the type, size and complexity of the electrical generation and distribution system:

• Load flow studies

• Fault level studies

• Motor start-up and voltage depression studies

• Transient stability studies

• Power factor studies

• Harmonics penetration studies

• Power system reliability and availability studies

• Relay settings/protection studies

Modelling software used for system studies shall be agreed in advance. OPQL shall review and approve

software tools to be adopted (or propose alternatives). These shall accredited industry recognised

software. EDSA, ETAP or CYME suite of software programs created by CYME International Inc. Power

Engineering Software are all acceptable.

Safety and Operabilit y (SAFOP) Reviews

The requirement for SAFOP reviews shall be determined as part of OPQL Process Risk Management

programme and (where required) will be finalised in consultation with OPQL TA. These shall ideally be

facilitated by an independent agency not involved in the design of the electrical system. Attendance

should include a senior representative with significant knowledge of the design of the system, operations,






maintenance representatives and OPQL electrical TA. Refer to document YPS1-4-SP-6928-001 Safety

and Operability Review (SAFOP) Terms of Reference for further guidance.

In order to ensure full range of safety, operability and operator task analysis, the SAFOP review shall be

performed in the early stages and validated in the final stages of electrical system design. The

engineering design and operability of the system is systematically questioned with key words to identify

any possible limitations and lack of flexibility and to assess the consequences on the operability and

safety of the system as well as safety of the operator. Smaller projects do not require these reviews.

Where required, they shall consist of the following:

SYSOP (System Operability) Review

The method for this is comparable to that of a HAZOP. Nodes and boundaries are defined using key

SLD’s etc. followed by a review of the overall electrical system design examining control systems, main

equipment of plant and their auxiliaries and consider any limitations found and their effect on the system

operability.

SAFAN (Safety Analysis) Review

The SAFAN is very similar to “What-if” reviews performed as part of the OPQL PRM programme. This

will examine hazards present in construction, commissioning and operation of electrical installation and

consider them in relation to the safety of personnel who are to operate, work or be in the vicinity of the

equipment.

OPTAN (Operator Task Analysis) Review

This will look at the probable tasks to be undertaken by both the control room and the field operator

during normal and abnormal conditions. It will also review the instructions and measures built-in to

prevent human error. The OPTAN review is best performed towards the end of engineering design when

operability aspects are reasonably well defined and the relevant vendor documentation is available.

2.10. Electr ica l Deta i l ed Desig ns

Engineering detailed design shall be executed against a defined scope of work (usually multi-discipline)

and managed by an OPQL appointed project engineer or discipline specialist. The engineering contractor

shall not deviate from this scope without approval from the OPQL representative. Typically OPQL require

project reviews at 10% (confirmation of base scope), 50% (mid-design review) and 90% (after first formal

issue, constructability reviews etc).

The requirements of OPQL Engineering and Procurement Procedure FAC 223 shall be complied with.

The focus is on compliance with the defined project electrical engineering requirements while managing

schedules and man-hours within agreed limits. Detail designs shall be incorporated into a construction

work package in an approved OPQL format.

OPQL Management of Change PRM requirements shall be complied with. PRM deliverables include Pre-

Start Safety Reviews (PSSR), revisions to operations manuals, identification of training requirements and

preparation of planned maintenance routines (PMR’s). Where instructed, these shall be prepared by

engineering contractor in an approved format. Refer to Appendix F for sample PMR format.

Commissioning requirements shall be taken into account during the design and included within the project

deliverables.






3. EQUIPMENT SPECIFICATION AND SELECTION PHILOSOPHY

3.0. General

All electrical equipment should be specified as being of a good quality, be fit for its intended use and

designed/manufactured to recognised industry standards without “gold plating”. Equipment should be

selected from manufacturers standard product ranges wherever possible. If engineering contractors or

equipment suppliers consider that any of the listed or referenced specification requirements result in

avoidable additional cost then this shall be brought to the attention of OPQL.

Refer to Appendix C for guidance concerning selection of bulk items and minor equipment. OPQL carry

stocks of commonly used cables, cable racking, trays etc. Engineering contractors are required to verify

and use items from OPQL stock lists wherever it is feasible to do so.

In general, OPQL shall adopt (and accept the use of) QP codes and standards and are obliged to follow

good industrial practice but it is noted however that application of QP codes and standards is not

mandatory within the DPSA. Refer to Appendix B for the list of codes and standards that are

recommended for use when selecting and specifying equipment for OPQL managed facilities.

Engineering contractors working on behalf of OPQL shall comply with these requirements. Where QP

codes and standards are used for major equipment procurement, it is required that a project specific

addendum specification and data sheets (listing accepted deviations) be prepared, suitable for open

tendering in lieu of a dedicated project specific specification. This shall be approved by the OPQL TA

prior to issue. The substitution of other standards requires prior approval from OPQL TA.

For tendering purposes, the approved project specifications, datasheets drawings and OPQL/QP codes

and standards are compiled into a requisition package. Where instructed, engineering contractors shall

prepare this requisition. The OPQL buyer issues the requisition as an “Invitation to Tender” to all

companies on the pre-approved bid list. Please refer to document 410924-8-PS1E-MR-0001-001 for an

example requisition in an approved format. Management of all bidder correspondence up until order

placement is an OPQL responsibility.

The requirements of OPQL Engineering and Procurement Procedure FAC 223 shall be complied with.

OPQL will make available their Approved Suppliers Lists for use during equipment specification. Where

requested, engineering contractors shall supply suggested bid lists for potential suppliers. Inclusion of

suggested suppliers within the OPQL approved suppliers bid list will be determined by OPQL at time of

tendering.

Unless otherwise agreed in writing, all electrical equipment shall be new and unused. Equipment shall be

manufactured with proven state of the art technology. The equipment shall not be prototype or from a

new product line that is not proven earlier in the oil and gas and petrochemical industry. The equipment

shall be designed for a service life of at least 20 years.

All electrical equipment shall be suitable for the site and environmental conditions as specified in section

2.2 Environmental Conditions and the respective equipment Data Sheets and Project Specifications.

Auxiliary supply voltages shall be selected compatible with the intended installation location. Refer to

section 2.8 for specific details.






All electrical equipment shall be designed and sized to operate at the specified design ambient

temperature. For batteries, the maximum design ambient temperature shall be considered while for

electrical heat tracing, minimum ambient temperature shall be considered.

Where appropriate, outdoor equipment shall be protected with suitable sun-shading. The ingress

protection for equipment enclosures shall be minimum IP55 as per IEC 60529. Weather shelters with

open sides shall be considered as outdoor installations. Indoor equipment shall normally be installed in

rooms having HVAC systems. The ingress protection for the equipment enclosure shall be minimum IP42

as per IEC 60529.

The atmosphere throughout all OPQL managed installations shall be considered to be corrosive, as

normally associated with oil and gas processing plants, refineries, chemical plants, LNG plants, offshore

platforms, industrial sites and the like. In addition, for offshore and coastal locations, the atmosphere

shall be considered as salt laden with presence of H2S. High humidity is experienced in all areas and

condensation will occur on all equipment during some period of their lifetime and therefore all

components, nuts, bolts and washers etc. shall be of corrosion resistant material and shall be

tropicalised. Anti-condensation heaters shall be provided where specified in their respective Engineering

Standards.

Equipment like main generators, emergency generators, distribution transformers, VSD’s, AC UPS

system, DC UPS system, batteries and switchboards shall be installed in non-hazardous areas. Only in

exceptional (and unavoidable) cases, shall these be installed in hazardous areas in specially designed

rooms.

3.1. Generators

HV GT Synchronous Generators

The generator, generator control panel and auxiliaries shall comply with QP Engineering Standard for HV

Gas Turbine Driven Synchronous Generators ES.2.14.0001. Engineering contractor shall prepare project

specific data sheets prior to tendering this equipment. The generators shall be procured as a complete

package along with the gas turbines. The kVA rating of the generator shall be such that it does not limit

the output of prime mover over the specified operating temperature range. The generator shall be sized

to have at least 10% spare capacity for future.

The generator rated power factor shall be 0.8 lagging, unless otherwise specified in the Generator Data

Sheet.

Generators shall normally be air-cooled. Use of water-cooled generators shall be subject to approval byOPQL TA.

The rating, type, characteristic and other technical parameters of the generators shall be based on the

mode of operation i.e. island mode or parallel operation with other generators or parallel operation with

third party feeders or any combination of these.

Where generators are being added to existing electrical systems, studies are required confirming

increased short circuit ratings are within the limits of existing equipment ratings.

Based on the application, the overload capacity, impact loading capacity, active and reactive power

sharing, speed variations, response time, reactance and inertia etc. shall be decided and indicated in the

project addendum specification and data sheets..






The generators shall be provided with the following controls:

• Manual and automatic synchronising with a check synchronising relay and a dead bus-bar

override

• Manual and automatic voltage control

• Reactive power sharing among various generators

• Power factor control to keep the generator power factor constant when operating in parallel with

third party supplies

• Speed control with droop characteristic when operating in parallel with other sets

• Isochronous control in island operation

Details of controls, metering, alarms and indications shall comply with requirements of QP Engineering

Standard for HV Gas Turbine Driven Synchronous Generators ES.2.14.0001 unless otherwise stated ondata sheets.

Each generator set shall normally be provided with its own LV auxiliary switchboard for supply and control

of all its motor driven auxiliaries. For new installations this switchboard shall be treated as an emergency

switchboard and shall be provided with an essential supplies feeder (derived from the emergency

switchboard). Generator LV auxiliary switchboard supply arrangements for existing installations shall be

determined case by case and approved by OPQL TA.

For installations having captive power generation only, appropriate black-starting requirements shall be

provided for the facility (this can be either HV or LV). Requirements for dual fuelling of GT’s shall be

considered in conjunction with other platform constraints. It is noted that reliability of dual fuelled

equipment is often inadequate. This shall be duly considered when specifying and selecting equipment.

Diesel Engine Driven Generators

Offshore diesel fuelling costs are a significant operating expense and diesel fuelled gensets should only

considered for temporary platform power plant, standby systems or for base load plant where a reliable

gas supply is unavailable.

These Generators shall comply with the requirements of QP Engineering Standard for Diesel Engine

Driven Generators ES.2.14.0002 and associated data sheets (ES.2.13.0002). Engineering contractor

shall prepare project specific data sheets prior to tendering this equipment. The Diesel Engine Driven

Generators shall be procured as a self-contained complete package along with Diesel Engine and shall

be subject to any of the following applications:

• Standby or Essential/Emergency Operation

• Black Start Facility

• Base Load Power Generation

The package shall be complete with AVR, Generator Control Panel and Generator Breaker. The

Generator Control Panel shall contain AVR controls, metering, indications, annunciations and protective

relays for the generator. The generating set shall be hooked-up to the switchboard through the incomer

circuit breaker in the switchboard. Additional local breaker near to the generator shall be provided in

those cases where the generating set is located away from the switchboard to which it is hooked-up and

local isolation is essential.






Necessary hardware for automatic mains failure detection shall also be provided for Standby/Emergency

Generators.

Generators supplied for emergency power should have their own self contained (preferably gravity feed)

diesel fuel storage suitable for 8hrs continuous running on emergency power. There should be sufficient

diesel storage capacity on the platform to provide a total of 24hrs operation of the emergency power

system. The diesel fuel transfer system (to the emergency generator fuel storage tank) should be

functional when platform is operating on emergency power. Refer also to QP-PHL-S-001 Corporate

Philosophy for Fire and safety, section 14; Emergency Power Supply System.

Generators used to provide electrical power to firewater pumps shall comply with the requirements of

NFPA 20. Engine staring systems in particular require special consideration. Protection systems are

normally inoperative when running under duty conditions and NFPA 20 compliant sets are configured as

“run to destruction” thereby protecting the primary asset.

Generators of sizes up to 1250 kVA shall be supplied at LV. Above 1250kVA, generators shall normallybe HV.

Generators shall normally be air-cooled. Use of water-cooled generators shall be subject to approval by

OPQL.

The emergency generators shall feed the following loads:

• Electrical loads essential for safe shutdown of the plant and personnel safety

• Emergency lighting

• Plant instruments, as applicable

• Communication equipment

• Fire and gas detection system

• Vital UPS system battery chargers ( AC and DC)

• Fire fighting equipment

• Helicopter landing area perimeter and obstacle lighting

Motor starting requirements and black-start load sequencing shall be duly considered when sizing of

generators. The generators shall be sized to have at least 10% spare capacity for future load growth at

the maximum operating temperature, net of auxiliaries after considering all other factors.

The facility shall be provided for synchronisation with normal supplies to enable full load testing of the

emergency generators without operational disturbance.

3.2. Neutr a l Eart h in g Resis to rs

The neutral earthing resistor shall comply with the requirements of QP Engineering Standard

ES.2.14.0085. The NER shall be housed in a sheet metal enclosure and shall be naturally ventilated.

The resistance elements shall be made of stainless steel alloy in a grid formation unless otherwise stated

on the data sheets. NER’s shall be rated to withstand the specified fault current for minimum 10 seconds.






3.3. Swi tchgear

General

Switchgear shall be of the compartmentalised metal clad type design to minimise any risk of developing ashort-circuit or the non-contained propagation of a short-circuit. It shall ensure personnel and operational

safety during all operating conditions, inspections and maintenance. The connection of main, control and

auxiliary cables and the equipping and commissioning of spare panels whilst the switchgear is live and in

operation shall be possible.

All switchboard components e.g. circuit breakers, main horizontal and vertical bus bars, bus bar joints,

bus bar supports etc. shall be designed to withstand the maximum expected short circuit level for a

minimum time of 1 sec.

All switchgear and associated equipment fed from generators and transformers shall be rated at least

125% of the rating of maximum number of generators and/or transformers (ONAF) simultaneously

feeding it including future expansions. The bus-section circuit breaker shall have rating equal to that of

the rating of the largest incomer circuit breaker.

Local operation of high energy potential equipment is discouraged. All HV switchboards shall have

facilities for remote operation. LV switchgear incoming, bus section and large outgoing feeders shall also

have remote operation facilities.

The application of intelligent switchgear and multifunction microprocessor based numerical protection

systems, in combination with electrical network control shall be considered the norm for all new

installations. Automatic protective systems shall be designed to achieve selective isolation of faulted

equipment with minimum delay. In any event this shall be within a time corresponding to the short circuit

current withstand capability of equipment, system stability limits and the maximum fault clearance times.

Adequate and selective phase short circuit and earth fault protection shall be provided, due regard being

given to the magnitude of short circuit currents and method of system earthing. The type and

characteristics of protective devices shall be selected according to application and shall be compatible

with existing platform facilities wherever possible.

Unless otherwise specified, unrestricted overcurrent protective devices shall have IDMT characteristics in

accordance with IEC 60255.

All signal interface requirements shall be as identified within section 2.5. Interposing relays shall be

provided as noted.

HV Switchgear

HV switchgear shall be in accordance with the requirements of QP Engineering Standard ES.2.14.0010.

The use of SF6 (Sulphur Hexafluoride) circuit breakers within switchgear is discouraged for environmental

reasons except where clear overriding technical advantages can be demonstrated.

Contactors used in motor starters shall have AC3 utilisation category as per IEC 60947.

HV switchgear and controlgear shall be of withdrawable type.

LV Switchgear

LV switchgear shall be in accordance with the requirements of QP Engineering Standard ES.2.14.0015.






Components of LV switchgear shall be standardised as much as possible and selected in accordance

with the current ratings.

Back-to-back design or double front design of LV switchgear shall not be considered unless floor space is

restricted, preventing the installation of single fronted equipment.

All LV switchgear incomers shall be provided with breakers/isolators. The choice of incoming isolation

shall be as per Data Sheet.

LV switchgear and controlgear shall be of withdrawable type. Equipment to be typically Form 4, type 5,

however Form 4, type 4 may be acceptable. To be agreed with OPQL TA on a case by case basis.

Configuration of Switchboards

For all main switchboards, the number of sections shall be two, with each bus-section having a 100%

rated incoming circuit.

For interruptible, maintained supplies to essential and emergency services, a separate switchboard

should be provided. The normal feeder to this switchboard shall be derived from the mains power system

and the standby circuit from an emergency diesel generating set. An automatic changeover system shall

be provided to changeover to the standby circuit in case of mains failure.

Duplicate (double) bus-bar arrangements are occasionally required for the principal high voltage

switchboards in a plant, e.g. main generation switchboards or intake stations. Their use shall be justified

on the basis of requirements of very high availability. Duplicate (double) bus-bar systems are not

normally be considered for offshore applications.

For non essential loads, and remote installations supplied by subsea cables, switchgear with a single

100% rated incoming section can be considered.

Operating Philosophy of HV and LV Switchboards

The requirements for controls and interlocks will influence the physical size of some circuit breaker and

contactor cubicles. This shall be taken into account in the sizing and layout of switchgear as a whole unit

and in the interchangeability of individual units, trays and trucks. Details to be included on project data

sheets.

In the majority of plants, the normal operating position of switchboard incoming and bus section circuit

breakers shall be as follows:

• For the upstream HV switchboards the bus-section circuit breakers shall be operated normally

closed on switchboards at intake stations, generation stations and distribution stations.

• For downstream HV and LV switchboards the bus-section circuit breakers shall be operated

normally open. When a section of bus bars or a feeder transformer is being taken out of service,

the normal operation of the bus-section circuit breakers shall be a manual function, carried out for

the purposes of maintenance or restoration of supplies following fault on an incoming feeder.

The configuration of intake, power plant and distribution switchboards shall permit one section of the

switchboard to be taken out of service while still maintaining the normal plant operations. Operational

loads shall be distributed on opposite sides of the board.






Spare Cubicles

HV switchboards shall have at least two spare outgoing cubicles on each busbar section. The type and

rating of the spare cubicles shall be decided based on the type and rating of feeders provided in the HV

Switchgear. All spare cubicles shall be fully equipped.

LV switchboards shall have spare cubicles, for future installation of additional outgoing circuits equivalent

to approximately 30% of the number of circuits initially utilised. Unless otherwise shown on the data

sheets, there shall be a minimum of two circuits of each size and type of consumer (e.g. outgoing static

feeder, outgoing motor feeder). Spare cubicles shall be fully equipped. Cubicles in excess of 30% can

be semi-equipped.

Choice of 3-pole and 4-pole LV Circuit Breaker

The neutral circuit of each transformer and generator incomer shall be connected to the earth bus-bar by

bolted links so that the connection is physically located on the busbar side of the neutral earthing facility.

This isolating facility shall be either a bolted link or one of the poles of a 4-pole circuit breaker. All earth

links shall be labelled 'neutral earth link'. Provision shall be made for the installation of CT’s on each

incoming neutral connection, both before and after the point where it is earthed, and on the connections

to the earth busbar.

Ring-main Units (RMU’s)

The use of RMU’s can be considered for simple radial feeder distribution switchgear typically supplying

remote unmanned facilities powered from host platform (PS1). Refer to YPS1-4-SP-6928 RMU

Specification and also to Technical Note YPS1-4-TN-6920-001 Comparison of HV Switchgear and Ring

Main Units for further guidance.

The use of RMU’s in their original application (i.e. as ring feeders distributing power to load centres) has

limited application offshore compared to conventional HV switchgear. OPQL TA should be consulted

before seriously considering this application to OPQL managed facilities.

3.4 . Busbar Duc t ing

Bus-bar ducting shall comply with the requirements of QP Engineering Standard ES.2.14.0019.

For LV systems where the current rating exceeds 1600 Amp, interconnection of equipment the use of

bus-ducting should be evaluated compared to the use of cables. Where used, the continuous and short-

circuit rating of bus-bar ducting shall be same as that of the switchgear, transformers and generators to

which these are connected.

In HV systems, decision of using bus-bar ducting shall be based on the number of cables used for

interconnection of equipment. Where the number of cables required is more than three per phase, the

use of bus-ducting should be evaluated compared to the use of cables.

3.5 . Power t rans fo r mers

The transformers shall comply with the requirements specified in QP Engineering Standards for Liquid

Filled Power Transformers ES.2.14.0020 and Dry-Type Power Transformers ES.2.14.0022.

The transformers for outdoor use shall be oil filled type. Sealed type transformers shall be specified for

ratings less than 5 MVA. Transformers 5 MVA and above shall be provided with membrane type splitconservator.






Transformers are no longer manufactured with Poly-Chlorinated Biphenyls (PCB’s), however this remains

an industry wide concern and it is prudent to request a certificate from the manufacturer stating that the

transformers are free of PCB’s.

Insulation liquid for offshore transformers shall be an environmentally friendly less-flammable liquid. The

Vendor shall preferably use a biodegradable fluid as the insulating liquid. Examples of biodegradable

fluids, manufactured from vegetable oil, classified as less-flammable available are:

• BIOTEMP®

• ENVIROTEMP® FR3™

• MIDEL 7131

Where biodegradable insulation oils are used, then bunding (for environmental containment purposes) is

not required.

For increased fire risk locations and indoor installations and where transformers are an integral part of a

switchboard, a VSD’s line-up of cubicles or a large UPS, dry-type transformer shall be used. Their

maximum rating should be up to 2.5 MVA.

The transformer rated duty shall be selected as at least 100% of the nominal continuous running kVA as

calculated in the Electrical Load Schedule for the short-term situation. Short term in this context relates to

the time duration of the project engineering and a few years after the plant is commissioned. In the case

of doubly fed switchboards each transformer shall be sized on the assumption that it is taking the entire

load on the switchboard, i.e. one feeder is out of service and the bus-bar section circuit breaker is closed.

Voltage regulation considerations shall also be taken into account when sizing transformers as there may

be a requirement to oversize the transformer to maintain satisfactory voltage tolerances.

It is also necessary to cater for long-term plant extension requirements. At least a 25% margin shall be

added to the rated duty to obtain the highest rated duty for continuous running. This margin shall be

obtained from forced air-cooling by attaching fans at a later stage. The fan fixings shall be incorporated in

the initial purchasing of the transformers. The cables, bus-bar ducting and switchgear in the primary and

secondary circuits of the transformer shall be sized initially for the currents corresponding to the highest

rated duty. The overload settings of the protection relays in these circuits shall be initially set to match the

rated duty, and only increased when the fans are added.

In accordance with IEC 60076, the transformer kVA rating refers to maximum secondary current and to

no-load voltage, not system voltage.

Consideration shall be given to provision of on load tap changers on intake transformers fed from thirdparty power sources.

Transformers equipped with a manual or automatic on-load tap changer shall have a separate switching

compartment so that the oil can be independently sampled and filtered during operation. All tappings

shall be on the highest voltage winding.

The automatic on-load tap changers of transformers working in parallel shall each have selective facilities

for independent, master and slave operation.

The percentage impedance of the transformers shall be as per IEC 60076, unless otherwise a different

value is specified from the considerations of short circuit and voltage drop during motor start up.






3.6. UPS Syst ems

System Autonomy

System autonomy shall normally be a minimum of 60 minutes in accordance with QP-PHL-S-001 QPCorporate Philosophy for Fire and Safety. Operational considerations may require a greater autonomy

period; however by their very nature such UPS systems will require very large battery banks. Autonomy

should be kept within reasonable limits consistent with maintaining vital supplies for safe operation and

shutdown of process plant following interruption of normal power.

AC UPS System

An AC UPS system shall be provided for vital supplies, continuous process loads and instrumentation

system requiring an uninterruptible maintained AC supply. The preferred voltage is 110v ac, single

phase. Other voltages (and 3 phase systems) may be required. Please refer to OPQL TA for guidance in

these matters. AC UPS systems shall comply with the requirements of QP Engineering Standard

ES.2.14.0040. The following loads are typically connected to the AC UPS system:

• DCS system

• ESD system

• Fire and gas system

• Local panels for critical packages

• Analyser room instruments

• Metering station instruments

• Annunciation panel

• PA/GA system

The configuration of UPS System, e.g. redundant, stand-by redundant, parallel redundant, will depend

upon the function of its consumers. For all configurations of the UPS System, 2 x 100% rated rectified

charger/inverter units with 2 x 50% rated back-up battery banks shall be provided. The UPS system shall

also be provided with stabilised static and maintenance bypass.

AC UPS systems shall be sized to take care of the crest factor of the load current. It is recommended

that a 10% margin in capacity be kept for future requirements. The UPS Distribution Board shall have at

least 20% spare outgoing feeders for future use. The largest outgoing feeder load shall not exceed 25%

of the AC UPS System rating.

DC UPS System

A DC UPS system shall be provided for vital supplies, continuous process loads and instrumentation

system requiring an uninterruptible maintained DC supply. The preferred voltages are 24v and 110v DC.

Other voltages may be required as determined by characteristics of the supplied equipment. Please refer

to OPQL TA for guidance in these matters. DC UPS systems shall comply with the requirements of QP

Engineering Standard ES.2.14.0044. The DC UPS system shall be provided to feed the following:

• Switchgear control

• Critical lighting and navigational aids

• DC motors, (as in GT emergency lube oil systems and diesel engine starting systems)






• Telephone system

• Fire alarm system

• Communication equipment

• Solenoid valves

• Telecom

• SCADA

The DC UPS system shall comply with the requirements of QP Engineering Standard ES.2.14.0044. The

DC UPS system shall typically comprise 2 x 100% rated rectified charger units and 2 x 50% rated back-up

battery banks.

It is recommended that a 10% margin in the capacity shall be provided for future requirements. DC

Distribution Board shall have at least 20% spare outgoing feeders for future use.

Batteries

Batteries shall be of adequate capacity to meet the back-up requirements for the required duty cycle and

to take care of future load margin of 10%. While sizing the batteries, temperature correction factor and

ageing factor shall be duly considered.

For both AC UPS and DC UPS systems, Ni-Cd batteries shall be specified. These should be past gel,

sealed for life type. Lead acid batteries are acceptable for engine starting applications.

In exceptional conditions (where space is a constraint), valve regulated lead-acid (VRLA) batteries with

absorbed electrolyte in a micro porous structure may be accepted. In such installations, close control of

working temperature is essential. Please refer to OPQL TA for guidance before specifying VRLA

batteries.

3.7 . E lec t r ic Motors

Asynchronous (Squirrel cage) induction motors shall be specified on account of their robust construction

and lower capital cost. Synchronous motors of the same rating as squirrel cage induction motors are

more efficient but have higher capital cost. For applications where power factor compensation is

beneficial and cost permits, synchronous motors may be used. This section is not applicable to motors

for downhole pumping applications (ESP’s). These are considered elsewhere within this BoD.

LV induction motors shall comply with the requirements of QP Engineering Standard ES.2.14.0035. HVinduction and synchronous motors shall comply with the requirements of QP Engineering Standard

ES.2.14.0030. The purpose of the driven equipment shall be considered when sizing motors and the

appropriate de-rating factors applied (typically a 10% margin is required). All motors shall be rated for

continuous duty except for cranes/hoists/engine starting which may be rated for the envisaged duty cycle.

All motors shall be designed for Direct On Line starting unless otherwise other methods of reduced

voltage starting are specifically mentioned.






The recommended power ratings of electric motors in relation to system voltages are:

Motor Rating System Voltage

Up to 132kW 415v

132kW to 185kW 415v or 3300v (HV preferred)

185kW to 1000kW 3300v or 6600v

1000kW to 4000kW 6600v or 11000v

Above 4000kW 11000v

The above limits are a guide and there may be instances where larger machines may be justifiable.Conversely, care should be exercised when specifying motors at the upper limits of their voltage range as

starting currents may cause excessive voltage depression on starting. Switchgear circuit breaker

limitations may also be an issue and shall be finalized prior to selecting voltage rating and supply source.

It is recommended that all motors above 30kW be provided with anti-condensation heaters. Integrated

Motor Control Systems (IMCS) which are micro-processor controlled motor starters and with additional

drive monitoring, protection features and self-diagnostic and communication facilities shall be considered

for new installations.

The use of DC motors shall be limited to special applications; for example emergency lube oil pump

motors on large rotating equipment, engine starting systems etc.

3.8. Cabl es, Wires and Suppo rt s

All cables used on OPQL managed facilities shall be specified and selected in accordance with the

requirements of OPQL General Cable Specification, Document 000000-4-XPS1-SP-0001-001.

Cable types H1 and H2 are suitable for 1900/3300V but specification of these is discouraged for reasons

of standardisation and HV cables should normally be specified and selected from H3 and H4 ranges

(6350/11000V).

Cable support systems shall be specified and selected from manufacturers GRP product ranges.

Galvanised systems are not acceptable. Cable trays shall be perforated and ventilated with the holesoccupying 30% or more of the tray area. This is required to satisfy “freely ventilated” criteria as detailed

within IEC 60092, Annex A, Installation methods E or F. Refer to Appendix C for more detailed guidance

concerning selection and specification of these items.

Switchroom and equipment plant room ceiling grid support systems shall be selected from Oglaend,

Norway product range (or approved equivalents).

OPQL carry stocks of commonly used cables, cable racking, trays etc. Engineering contractors are

required to verify and use items from OPQL stock lists wherever it is feasible to do so.

Refer also to section 4.1 for cable design and application details.






3.9 . Meter ing , Pro tec t ion and Cont ro l equ ipment

The electrical system shall be specified as equipped with adequate controls, metering, alarms and

indications for checking, monitoring and control of the power system. Metering shall be provided to keep

a record of power consumption and measurement of current, voltage, power, frequency, power factor etc.

The electrical system shall be equipped with automatic protection which shall provide safeguards in the

event of electrical equipment failures or system mal-operation. The selection and specification of

switching and protective devices, control circuits and associated auxiliary equipment shall be in

accordance with the respective GT gensets, HV and LV switchgear specifications. This shall normally be

included within the packaged equipment scope of supply.

3.10. Power Management Systems

A dedicated Power Management System (PMS) for the electrical generation and distribution system shall

be specified for all larger networks and where centralised supervision, control and metering is required.This system shall comply with the requirements of QP Engineering Standard for Power Management

System ES.2.14.0065. The requirements of OPQL Specification for Power Management Systems,

document No. 403086-4-PS1E-SP-0002-001 shall also be taken into consideration. Refer to section 2.4

for further details.

3.11. Packaged Equip ment

The engineering contractor shall prepare a project specific specification and data sheets outlining specific

requirements for the packaged equipment. The equipment shall be in general compliance with the

following documents with exceptions as noted:

EFS.00.08.05 – QP General Specification for Packaged Equipment

The above document outlines the general requirements for design, manufacture, testing and

commissioning of packaged equipment.

EFS.00.08.05 – QP Electrical Requirements for Packaged Equipment

The above document outlines the electrical requirements for design, manufacture, testing and

commissioning of packaged equipment. The voltage levels specified within this document are not

relevant to most of OPQL managed facilities. Please refer to section 2.8 of this BoD for further details.

000000-4-XPS1-BD-0001-001 – Electrical Basis of Design

All electrical bulk materials and minor equipment shall be selected in accordance with Appendix C of the

above document. It should be noted that all cable racking and supports shall be GRP. The package

system voltages, frequency and power factor shall be compatible with platform systems defined within

section 2.8 of the above document.

000000-4-XPS1-SP-0001-001 - OPQL General Cable Specif ication

All package cabling requirements shall be in accordance with the above document.

HES-027 - Lifting Equipment Control and Operations Policy

All lifting devices and aids on all equipment shall comply with requirements defined within the above

document.






3.12. Var iab le Speed Dr i ves and ESP’s

Where instructed, the engineering contractor shall prepare project specific specifications and data sheets

for this equipment. The specification for a VSD shall include all responsibilities, design activities,

materials, requirements, tests, documentations, instructions, and be reviewed by electrical, instruments,

drilling, process and artificial lift specialists prior to issue for tender. ESP Package Specification YPS1-4-

SP-6922-001 and associated datasheets is indicative of what is required and shall be used for guidance.

The purchase order of a VSD shall make provision for include start up assistance but not the site

installation, installation materials and downhole cables. The manufacturer shall confirm capabilities (and

where support is based) within his quote.

OPQL have supply agreements with some ESP service providers and preparation of equipment

specifications for some equipment is not always necessary.

Where deemed necessary by one of the parties involved, a pre-ordering meeting shall be arranged to

define clearly the scope, individual responsibilities, test methods and documentation requirements.

Attendance of all disciplines, including downhole and artificial lift specialist is recommended.

To avoid incompatibility issues, the various components which comprise an electrical Variable Speed

Drive System shall normally be purchased as a complete package from a single supplier. The scope of

supply of such a package will typically include the following items:

• Specialist design services for ESP package to suit specified performance and interface

requirements

• Variable speed drive unit, direct-on-line or soft starter

•

Active or passive harmonic filter

• Transient voltage surge suppressor

• Surface termination and interface panel for downhole instrumentation (may be part of VSD)

• ESP HV step-down transformer (multi-tap or dual winding as required)

• ESP HV step-up transformer

• ESP Wellhead HV terminations junction box (EEx certified)

• Wellhead outlet and cable to surface junction box

• Downhole pump string (typically comprising, downhole pumps, seal systems, motors, instrument

monitoring for pressure, temp and pump/motor protection, terminations)

• Downhole cable and clamps

• Spare parts, consumables and specialist tools

It should be noted that OPQL require purchase of 50% back-up for all downhole equipment (including

downhole cable). This is to avoid rig downtime in event of equipment damage.

Engineering contractors should take care when specifying control interfaces to avoid protocol

mismatches. Historically, there have been several instances where this has occurred. All ESP

equipment shall have remote start and monitoring capability.

Well fluid properties (e.g. presence of H2S) shall be taken into account when specifying all downhole

equipment and components.






3.13. HVAC Syst ems

The HVAC equipment requirements shall be identified and specified by the engineering contractor within

a Functional Requirements Specification and associated data sheets. This specification shall include a

clause excluding the use of Ozone depleting refrigerants. Standard industrial HVAC equipment should be

used wherever it is feasible to do so. HVAC systems can be specified as supplied by manufacturers as

single components or integrated into packaged units and will typically include the following equipment as

appropriate:

• Air Handling Units (AHU’s)

• Chilled Water Units (Compressor type)

• Chilled Water Units (Direct expansion type)

• Humidifiers and Dehumidifiers

• Duct air heaters

• Mechanical ventilation systems and fans

• Sound attenuators

• Inlet air filters/coalescers

• Fire and gas air shut off dampers, and weather louvers

• Internal and external ductwork and air terminal boxes

• HVAC control systems

3.14. Nav igat io nal A id s

Marine Navigational Aids

Marine and air navigational aids are required for all OPQL mobile and fixed offshore installations. These

shall generally comply with the requirements of QP Engineering Standard for Navigational Aids

ES.2.14.0003 unless otherwise stated. Refer also to OPQL Phase 3 Marine Navigational Aids

Specification YPS1-4-SP-6927-001. These shall comprise the following:

• Main lights

• Secondary lights

• Subsidiary lights

• Fog signals

• Secondary fog signals

• Underdeck illumination of legs, risers and conductors

An alarm for the failure of main lights and fog signals shall be provided in the DCS system to give a

warning to the operator. These alarms shall also be provided for satellite platforms, structures and

unmanned installations.

Navigational Aids shall be capable of performing independently within the parameters specified in ProjectDatasheets and conform to International Association of Marine Aids to Navigation and Lighthouse






Authorities (IALA) O-114 standard requirements. All equipment and components shall preferably be of

the Vendor’s standard product line.

Marine Navigational Aids shall be equipped with batteries having ninety six (96) hours autonomy time.

Where 96 hours cannot be achieved the Vendor shall nominate the maximum capacity available. The

batteries shall be charged through on-board solar panels and/or battery chargers as detailed within the

data sheets.

Marine navigational aid lanterns shall preferably incorporate LED's and shall be of the omni-directional

type, emitting a white light as an aid to shipping. Marine navigational aid lanterns shall have an apparent

intensity of not less than 1400 candelas in any horizontal direction and shall be visible for a distance of

not less than 10 km from all points more than 5 metres above sea level, when the visibility is not less than

10 km. If this is not attainable with LED’s the Vendor shall recommend what intensity and range is

available.

Where LED’s are not available, the vendor may as an alternative, offer lamps. If lamps are offered, eachlantern shall be fitted with an automatic, six position lamp changing facility to achieve a minimum of 6000

burning hours. The lamp changer shall be automatically deactivated if no serviceable lamps are available

and, where specified on the data sheets shall activate contacts for a remote alarm. The lamp changer

shall have reverse polarity protection and shall include provision for lamp filament focusing.

Each lantern shall show the letter “U” in Morse code at intervals of not more than 15 seconds. Where

more than one lantern is installed on a platform, synchronization (GPS synch preferred) shall be provided

to ensure that all lanterns simultaneously flash the specified characteristic code. Failure or malfunction of

one or more lights shall not interfere with the operation of the remaining lights.

Each Navigational Aids lantern shall contain an integral photocell to control lantern operation. Photocell

failure shall result in the lantern operating.

Lanterns shall be free standing with provision for fixing directly to the platform steel work. The mounting

hardware shall include three bolt self leveling hardware, washers and self locking nuts, complete with ISO

metric threads.

The lanterns shall be equipped with 360° clear acrylic lenses fitted with bird spikes.

Helideck Perimeter and Obstruction Ligh ting

The helicopter landing area on all offshore platforms and structures shall be provided with perimeter

lighting, comprising alternate omni-directional yellow and blue lights. The lights shall not be below the

level of the deck and shall not exceed a height of 0.125 metres above the deck. The lights shall be

spaced at interval of 3m around the perimeter. Helideck lighting shall conform to the latest edition of CAA

CAP 437.

Tall structures, stacks, columns and tall vessels etc. shall be provided with obstacle lights and/or markers

as per the guidelines of International Civil Aviation Organisation. The obstacle lights shall be provided on

the top most level of the structure. Where it is not practical e.g. flare tower tips, these lights shall be

provided at a lower level with suitable heat shields based on radiation calculations.

For offshore installations, obstacle lights shall be installed at suitable locations to provide the helicopter

pilot with visual information on the proximity and height of objects which exceed the height of landing area

and are close to landing area.

Obstacle lights shall be connected to emergency power supply.






It is prudent to seek the guidance of the Chief Pilot, helicopter operations (Gulf Helicopters at time of

writing) concerning changes/additions to all helideck and obstruction lighting.

3.15. Cathod i c Pro tec t ion Sys tems

Cathodic protection is an electrochemical technique for preventing corrosion of buried or immersed

metalwork to an electrolytic media surrounding the metal. This can be achieved either by sacrificial

means or by applying DC current to the metal surface by external power supply source. The preferred

means of cathodic protection is to protect against corrosion by the use of sacrificial anodes.

The cathodic protection shall be provided for underground pipelines, tank internals, tank bottoms,

submerged pipelines, offshore steel structures etc. The cathodic protection system shall be designed and

installed as per the guidelines of QP Engineering Standard ES.2.14.0045.

3.16. Electr i c Process Heaters

Electric process heaters shall comply with the requirements of QP Engineering Standard for Electrical

Process Heaters ES.2.14.0005. General guidance is also provided within OPQL Specification No.

410924-8-PS1E-SP-0001-001; Glycol Re-boiler Electric Heater Skid.

The heaters shall be either contactor controlled having on/off facility or thyristor controlled as per process

requirements. For thyristor-controlled heaters, the power of each heater shall be controlled by firing of

thyristors according to zero-crossover mode i.e. where the voltage or current is zero.

Over-temperature protection for the heaters and the thyristor control panel, heater protection for low

flow/low level and earth leakage protection device in the power supply circuit shall be provided.

3.17. Electr i c Motor Operated Valve Act uator s

Electric Motor Operated Valve actuators (MOV’s) shall generally comply with the requirements of QP

Engineering Standard ES.2.14.0036. These shall be provided with integral starters. The necessary

local/remote selector switches, start/stop switches or push buttons, torque limit switches etc. shall be

provided on the actuator for local and remote control depending on the mode of selection. Failure of the

torque limit switches shall not cause any damage to the actuator motor.

The valves to be actuated with electric motor shall be identified by Process Department and shown on the

P&ID’s.

3.18. Electr i ca l Heat Trac ing

Electrical heat tracing systems shall comply with the requirements of QP Engineering Standard for

Electrical Heat Tracing ES.2.14.0004. The system shall be ordered as a packaged unit including design,

supply of tracers and cables, installation at site and all necessary control auxiliaries. In all cases where

electric heating is applied, each circuit shall be fitted with earth leakage protection devices in accordance

with hazardous area regulations.

3.19. L igh t ing , Smal l Power , Bu lks and Minor Equ ipment

For smaller projects, equipment should be selected compatible with existing platform equipment. Refer to

section 2.0 “Standardisation of Equipment and Materials” for further details. Please also refer to






Appendix C for guidance concerning specification of commonly used electrical bulk items and minor

equipment.

The use of incandescent lighting is no longer acceptable on OPQL managed facilities and should not be

specified.

3.20. D is t r ib u t io n Boards

Distribution board schedules shall be prepared in OPQL approved standard format by the engineering

contractor. Wherever feasible, these shall be installed indoor in non-hazardous air conditioned

equipment rooms. Equipment shall be specified and selected from manufacturer’s standard product

range where compliant with the following:

• Equipment to be fully fault rated

•

Ingress protection of IP42 minimum (if placed indoors), otherwise IP56 minimum• Ingress protection (doors open) to be IP23 minimum

• Equipment to be fitted with an ammeter

• Cables to be bottom entry via removable gland-plates

Specifications and data sheets should be kept to a minimum consistent with documenting the project

requirements. The following OPQL specification and data sheets can be used for general guidance:

• 410641-4-PS1R-SP-0001-001 – Distribution board specification

• 410641-4-PS1R-DS-0001-001 – Distribution board data sheets

3.21. Subsea Cables and Umbi l ica ls

Subsea cables and umbilicals shall generally comply with requirements of ISND Phase 3 Water Injection

Subsea Cable Specification and datasheets, documents YPS1-4-SP-6923-001 and YPS1-4-DS-6923-

001. Subsea cable J tube armour clamps shall have a ventilated spool piece (or equivalent) to avoid

reductions in current carrying capacity within J tubes.

Prior to tendering, subsea cable lengths shall be calculated precisely based upon subsea routing

drawings. There shall be due allowance made for route length variance, seabed undulations, J tube

risers and repair contingencies. A template for subsea route length determination is given in example

calculation YPS1-4-CA-6924-001. Subsea cable length shall be reconfirmed immediately prior to orderplacement.

OPQL policy is for subsea cables to be installed direct on seabed without trenching. There are a large

number of subsea obstructions in vicinity of ISND structures, giving rise to free span crossings typically of

the order of 3 to 5m. Subsea cables and umbilicals shall be specified suitably armoured to provide

seabed stability and withstand unprotected free span crossings as noted.






4. EQUIPMENT INSTAL LA TION DESIGN REQUIREMENTS

4.0. General

The electrical installation shall conform to good working practice and be of a high quality and safety in

general accordance with QP Engineering Standard for Electrical Installation Recommended Practices

ES.2.06.0001.

The electrical equipment shall be installed in accordance with the installation instructions and supporting

drawings provided by the manufacturer of the respective equipment. The design of the electrical

installation shall ensure that satisfactory access is provided for all operational and maintenance purposes.

Minor field equipment shall generally be EEx certified and suitable for installation in hazardous areas.

Refer to section 2.1 for further details.

Temporary installation work, required during erection of permanent installations, shall also comply with

the basic rules of design and engineering.

4.1 . Cab les , Rout ing Cons idera t ions and Accessor i es

General

OPQL carry stocks of commonly used cables, cable racking, trays etc. Engineering contractors are

required to verify and use items from OPQL stock lists wherever it is feasible to do so.

All cables used on OPQL managed facilities shall be specified and selected in accordance with the

requirements of OPQL General Cable Specification, Document 000000-4-XPS1-SP-0001-001. Multi-core

cables shall be given preference to single core cables. It is permissible to use single core cables for

practical and economic reasons (as in large LV feeders).

Cable types H1 and H2 are suitable for 1900/3300V but specification of these is discouraged for reasons

of standardisation and HV cables should normally be specified and selected from H3 and H4 ranges

(6350/11000V).

Cables for general use shall be multi-core armoured. Unarmoured cables shall only be used where

cables are routed entirely within accommodation areas and terminated into uncertified electrical

equipment which is not part of a safety critical or vital service.

Cable Sizing Design Basis

The sizing of LV cables shall generally be in accordance with OPQL LV Cable sizing document YPS1-4-

CA-6921-001 (noting that this document is currently being revised to align with cable sizing criteria

specified below). This is based upon tabulated data within IEC 60092-352 (Electrical Installations in

Ships – Choice and installation of electrical cables). Refer to Appendix J for details. Where cables are

individually sized, this shall be on the following basis unless specifically agreed otherwise with OPQL TA:

• Cables shall be selected from Cable Specification, Document 000000-4-XPS1-SP-0001-001.

• An ambient air temperature of 45oC shall be used.

• A steady state aggregate maximum voltage drop limit of 6% shall be applied (normally a 2% limit

for feeders and 4% for the final sub circuit).






• The maximum permissible voltage drop on motor starting shall be 15% with a starting/running

ratio of 6.5x (unless specific motor starting data is available).

• Tabulated current carrying capacities shall be in accordance with IEC 60092-352, Table A4,

Installation methods E, F or G.

• For LV cables, a cable installation grouping factor of 0.73 shall be applied (based upon a

maximum of 6 fully loaded cables, touching in accordance with IEC 60092-352, Table A6). In

general it is noted that cable installation grouping factors are conservative, given that most

offshore electrical systems function with 100% duty/standby basis and control cables carry very

little current. Thus heat dissipation in most instances will be well below that determined as worst

case by cable rating factors.

• For HV cables a cable installation grouping factor of 0.79 shall be applied, or if cables are

individually cleated (multicore) or in trefoil formation (single core) in accordance with IEC 60092-

352, Table A6 a grouping factor of 1.0 shall be applied.

• Cable impedances at a conductor operating temperature of 90oC shall be assumed.

• The short circuit conductor operating temperatures shall not exceed 250oC.

• The circuit design current to be based upon cable protective devices (short circuit, overload).

The tabulated current ratings within IEC 60092-352 assume the use of class 2 stranded high conductivity

copper conductors for fixed installations in accordance with IEC 60228 and are suitable for both HV and

LV cables. A 5% de-rating factor shall be applied where they are used for sizing HV cables unless

manufacturers tabulated ratings confirm otherwise.

Where class 5 conductors are used (flexible cables feeding mobile equipment), then manufacturerstabulated ratings shall be used or a suitable de-rating factor applied.

Cables carrying very large LV currents and all HV cables shall be individually sized. Temperature

excursions above 45oC are relatively infrequent and short duration and cable insulation is designed to

withstand short temperature excursions so an ambient temperature limit of 45oC is acceptable for

equipment specification and cable sizing purposes.

The following guidance is provided for equipment power factor (Cosø) and can be used in the absence of

specific manufacturer’s information:

• 0.8 for non motor feeders

• 0.58 to 0.9 for motor loads (size dependent)

• 0.3 for motor starting and fault calculations

Where engineering contractor wishes to use other sources of reference information for cable sizing, this

shall be agreed in advance with OPQL TA.

Battery cables and supply cables from battery backed systems shall be sized to take into account the

minimum voltage tolerance at end of discharge (this is typically 22.7V on a 24V DC system). Similarly,

field cables to solenoid valves etc. powered from 24V DC systems shall be verified as having a voltage

drop within the lowest voltage tolerance of the supplied equipment.

The detailed offshore environmental conditions to be applied are detailed within section 2.2 and voltage

drop considerations are detailed within section 2.7.






All power and control cables shall be in continuous lengths and cable joints shall be avoided wherever

possible. These will only be accepted in exceptional circumstances. Cable joints in hazardous area shall

not be permitted.

Cable routing and segregation

Offshore cables shall generally be routed on freely ventilated perforated cable racks in groups of no more

than 6 cables, bunched in a maximum of 1 layer (in accordance with IEC 60092-352, Annex A). Single

core cables pertaining to one 3 phase circuit shall be laid in trefoil formation. All cables shall be

adequately clipped. Cables carrying large currents shall have cleats spaced taking into account potential

fault currents. Adequate restraint is normally provided by clamps at 1m spacing on straight runs and

0.5m spacing on the bends; however the spacing shall be as calculated by the Contractor for the

applicable cable type and fault level. The fault level used for calculation shall be as per the rating of the

associated switchgear busbars, restricted by the largest fuse size possible (where appropriate). All trefoil

clamps shall be of an approved type tested design.

Instrument and telecommunication cables shall be routed on racks and trays segregated from HV and LV

power and control cables. For new installations (and wherever feasible in existing installations), HV and

LV cables shall be routed on separate racks and trays. For long continuous runs, there shall be adequate

separation between instrument and power cables to avoid signal interference.

Cable rack and tray support systems shall be specified and selected from manufacturers GRP product

ranges. Galvanised systems are not acceptable. Refer to Appendix C for more detailed guidance

concerning selection and specification of these items.

The minimum size for new external cable racks should be 200mm minimum and a minimum size for cable

trays of 150mm. Generally, new cable routes should allow a generous margin for future cabling

requirements (typically 25%). Judgement shall be applied however, and this shall be determined case by

case.

Cables shall be routed such as to minimize mechanical damage. Supplementary protection (kick plates,

removable rack covers, etc. shall be provided where necessary. Sun shielding shall be provided to

reduce effects of direct solar radiation.

Changes of direction in cable routes shall cater for the following minimum cable bending radii:

• LV cables: 10 times the cable OD

• HV cables (multi-core): 15 times the cable OD

• HV cable (single core): 20 times the cable OD

In all cases, the cable manufacturer's recommendations shall be adhered to.

Fibre optic cables or fibre optic cores in composite cables can be used for the transmission of signals and

data. Such cables shall be routed on trays and racks with other instrumentation cables.

All cables shall carry identification numbers (in an approved format) at each end.

Multi-cable Transit Penetrations

All bulkhead and deck penetrations, and where cables enter a pressurised room or shelter shall be

carried out using agreed proprietary multi-cable transits. Transit locations shall be logically designed

compatible with cable routing requirements (but kept to a minimum). The use of transits through roofs isto be avoided to reduce possibility of moisture ingress.






It is recommended that there is at least 50% spare capacity provided within transit frames on completion

of design. Transits shall always be used where cables pass:

• From a safe area to a hazardous area, separated by a gas-tight wall or barrier

• Through blast walls or fire walls

• Through solid decks

• Through walls and floors of enclosures or rooms to open areas

Care shall be taken during design (and installation) to continue the trefoil formation of single core AC

cables when passing through transits. Non-magnetic brass stay-plates are required within the transits

and each trefoil group shall pass through the same transit window.

Cables passing through transits shall be perpendicular to the transit for a minimum distance of 300mm on

each side of the transit. Suitable cable supports and fixings shall be applied to maintain the perpendicular

approach.

Cables routed in conduits

Wiring in conduits shall not be used in hazardous areas and is generally excluded in most offshore

applications except in specific circumstances (such as final droppers within non-hazardous equipment

rooms). Such installations shall comply with the requirements of BS7671 – Requirements for Electrical

Installations. Wires laid in conduits shall have minimum cross section area of 2.5mm² except for wiring

between a switch and a lighting fixture, when a minimum cross-section of 1.5mm² may be used.

For control wiring within panels, a minimum cross section of 1mm² may be used.

Cable Accessories and terminations

Cable glands shall be selected to suit the type of cable and termination box/enclosure and shall be of

appropriate type of protection for the hazardous area. Effective earth continuity shall be ensured between

the cable armour and the gland plate or the internal earth terminal. All LV terminations shall utilize cable

lugs. HV terminations shall normally be through heat shrinkable type termination kits, however for HV

motors and generators, the terminations shall utilize Elastimold/Bi-mold plug and socket connectors (or

other approved equivalent).

The armouring of multi-core cables shall be solidly earthed at both ends.

The armour and screen of single-core cables shall be earthed on one side. For longer cable lengths, due

attention shall be paid to open end voltages and consideration shall be given to the use of insulated

glands. The open end voltage shall not exceed 60V under full load rated current conditions and 430V

under maximum short circuit current conditions. Where packaged equipment requiring large single core

supply cables is required, guidance from manufacturers shall be taken into consideration. Single core

cables should be terminated using non-ferrous gland-plates.

All cables shall be terminated using approved cable glands, certified to match the equipment they are

glanded into. To avoid the use of non certified glands in hazardous areas, consideration shall be given to

standardising on certified glands only. This is not a mandatory requirement and shall be considered on a

project by project basis.

All cables and equipment shall be identified and tagged in accordance with OPQL DCC requirements.

Typically, projects (on request from DCC) will be allocated a block of cable and equipment tag numbers.This also includes temporary installations.






4.2 . L igh t ing and Smal l Power Ins ta l la t ions

General

Fluorescent lighting shall in general be used for area illumination. High-pressure sodium discharge lampsmay be used for practical and economic reasons in certain applications (e.g. compressor sheds,

underdeck lighting etc.) or large areas where colour rendering is unimportant. Where HP sodium lamps

are used, consideration shall also be given to providing supplementary fluorescent lighting to cater for re-

strike delays caused by momentary power failures.

Flood lighting shall be used for the open areas around process and production plants. High pressure

discharge lamps shall be used for flood lighting. Care shall be taken to avoid shadows in the working

areas and glare factor will require to be considered during the design. Low-pressure sodium lamps shall

not be used, as they constitute a fire hazard in the event of breakage.

All outdoor lighting shall be controlled by means of photoelectric cell with manual over riding control.

Where special requirements regarding colour distinction exist (for example laboratories), these shall be

met.

The use of incandescent lighting is not acceptable for any new installations on OPQL managed facilities.

Plant Lighting

Plant lighting shall comprise of following:

• Normal lighting

• Emergency (critical task) lighting

• Escape/Critical lighting

Normal and emergency lighting shall be fed by AC supply while escape/critical lighting shall be fed from

self-contained batteries. For hazardous areas, the preferred form of illumination shall be fluorescent

lamps with type of protection Ex-e. For standardisation purposes, the same type Ex-d or Ex-e lighting

fixtures should be used whether classified Zone-1 or Zone-2. Refer to Appendix C for details of preferred

equipment types.

If high-pressure discharge lamp fittings are needed in hazardous areas then they shall be of the Ex-d type

only. An isolating switch shall be included inside the fitting to prevent the light fitting from being energised

when it is not fully assembled.

Interior Lighting

Lighting fittings in closed buildings, which are classified as non-hazardous areas, such as offices, control

rooms, sub-stations, shall be fluorescent bi-pin, switch-start type, industrial or domestic type with high

frequency ballasts and power factor correction.

Illumination levels

Refer to Appendix E for recommended plant area illumination levels. This covers most (but not all)

situations. Please refer to OPQL TA for guidance if required.

Note that emergency lighting levels available are dependent upon the autonomy period of luminaires.

Most battery backed emergency luminaires are selectable to provide either 3hr or 1.5hr autonomy. The

light output with 3hr autonomy is approximately half that when selected for 1.5hrs. Generally, escape






lighting shall be set for 3hr autonomy and emergency (task) lighting shall normally be set for a 1.5hr

period.

A light loss (maintenance) factor of 0.8 is recommended for lighting illumination level calculations for all

indoor areas. For outdoor areas subject to dirt etc, a lower factor shall be used, determined by

circumstances.

Power supply considerations

Plant lighting shall be fed from dedicated lighting distribution boards installed within switchrooms. The

use of outdoor distribution panels is discouraged. Plant lighting distribution boards shall include 20%

spare outgoing circuits. Distribution board schedules shall be prepared in OPQL standard format.

Templates are available from OPQL DCC on request.

Lighting circuits shall be arranged to give a balanced load across the three phases at the distribution

board. All lighting circuits shall be with double pole isolation facility. Plant lighting circuits shall be single-

phase (phase and neutral) and protected with maximum 16 A fuses or MCBs. Lighting circuits shall not

be loaded higher than 12A.

Adjacent lighting fittings shall not be supplied from the same circuit. Lighting fittings shall be mounted on

the available structures and shall be so located that maintenance and lamp changing can be effected

without the use of ladders and scaffolding. In tall buildings, such as compressor and turbo-generator

houses, maintenance and lamp changing should be possible by using the overhead crane. When no

structure is available to support lighting fittings, lighting poles of adequate height shall be used to support

the fluorescent lighting fittings.

Plant lighting circuits that are adequately served by natural light shall be designed for automatic switching

via photoelectric relays. Manual over-ride facilities shall be provided.

External plant areas shall normally be switched from the distribution board. Where boards are lockable,

then external switching facilities shall be considered.

Internal lighting of non-process buildings and sub-station buildings shall be switched from inside the

building. The lighting installation in the control rooms shall be designed to enable groups of ceiling lights

to be switched off by the operator. The lighting fixtures shall be situated in such a way that reflection on

instrument windows and displays is avoided. Depending on type of instruments installed, dimmers may

be required.

Emergency and Escape Lighting

Fixed emergency lighting shall be installed at strategic points in the installations, including control rooms,switchrooms, fire-fighting stations, emergency response muster points, first-aid rooms, the main

entrances and in all other buildings and areas where required for safety reasons.

The location and electrical arrangement shall be such that danger to personnel in the case of a power

failure is prevented, and escape routes are illuminated. The emergency lighting system shall normally

consist of self-powered emergency lighting fittings with power derived from the emergency generator.

In the case of emergency diesel generator supply, a number of lighting fittings in the control room and the

basement of the control room, as well as field auxiliary rooms, shall have lighting fittings with self-

contained batteries to avoid complete darkness during start-up time of the diesel generator. All battery

backed lighting fixtures on offshore platforms shall be suitable for Zone-1 hazardous area.






The number of emergency lighting fittings to be installed as a percentage of the total number of fittings

shall be determined as follows:

• Control room 50%

• Switchrooms 30%

• Generator area 30%

• Utility areas 20%

• Muster points 20%

• Process areas 10%

• Administrative areas 5%

Critical task lighting shall be installed above equipment required for black-starting facilities (emergency

generator control panels etc.).

For escape lighting, the lighting fixtures shall have self contained batteries rated to maintain the lighting

for at least 60 minutes. Escape lighting shall be provided in all buildings to illuminate the way for

personnel leaving the building along defined escape routes to defined muster points.

Special Lighting

Special lighting, e.g. navigation aids, obstruction warning lights and aircraft navigation lights, shall be

installed in accordance with national and international standards. Long life lamps at reduced voltage shall

be used. The installation shall be backed up by an emergency supply system.

The illumination of any areas to be observed by TV cameras shall be designed in particular with regard touniformity of the level of illumination as well as to the location of the individual lamp fittings. The

illumination level to be maintained shall be compatible with the camera system utilised.

Helideck lighting shall conform to the latest edition of CAA CAP 437.

Power and Convenience Outlets

For maintenance purposes, an adequate number of 3-phase power outlets for movable equipment and

single-phase convenience outlets for the supply of portable tools and hand lamps shall be provided at

suitable locations.

Power outlets shall be rated for at least 100A and be suitable for outdoor installation. They shall normally

be located in non hazardous areas. The outlets installed in existing installations shall be compatible withexisting equipment. Refer to Appendix C for further details.

Convenience outlets shall have a single-phase supply voltage equal to the voltage selected for normal

lighting. The outlets installed in existing installations shall be compatible with existing equipment. For

industrial areas the outlets shall be rated for 16 A suitable for outdoor installation and shall conform to the

hazardous area classification. These shall have necessary mechanical interlocks and earthing facility.

An adequate number of convenience outlets for hand lamps and portable tools shall be provided at

suitable locations.

Plugs shall not be interchangeable with sockets of different voltages or current ratings nor shall it be

possible to insert an industrial type plug into an outlet suitable of Zone-1/Zone-2 hazardous areas.






All power and convenience outlets shall be protected by means of short circuit protective devices and

current operated earth leakage protective devices i.e. residual current circuit breakers (RCCB). The

RCCB operating current shall be 30mA for circuits less than 100A rating and 300mA for circuits above

100A rating. The operating time shall not exceed 30 msec.

4.3 . Ear th i ng and Bond i ng

The primary purpose of the earthing system is to reduce and control voltages on equipment to an

acceptable level under abnormal conditions and provide a conductive path to earth for fault currents. A

secondary purpose is to eliminate any risk of sparking in hazardous areas due to voltages under

abnormal conditions. Such conditions include equipment faults, static electricity build up or lightning

strikes. This document covers

Please refer to Appendix D for the primary and secondary earthing requirements to be adopted on all

OPQL managed facilities. Engineering contractor shall comply with these requirements. Please refer toOPQL TA for guidance if required.

4.4. Major and Packaged equip ment i tems

Packaged equipment encompasses a large variety of equipment from small pump-sets with simple

interfaces to major packaged equipment with many interconnected systems. The emphasis shall always

be for the engineering contractor to ensure a fully integrated system design without unnecessary

duplication of vendor documentation.

All interfaces shall be identified, validated and incorporated into the overall design, including the following

commonly encountered items:

• Supply source compatibility (voltages, frequencies, current ratings).

• Cable rack and tray requirements (within skid and external to skid)

• Cable entry sizes, compatibility, glandplate accessibility, MCT locations, etc.

• Cable size compatibility (with terminations etc.).

• Skid limit junction boxes, termination panels

• Lighting and small power requirements

• Serial link and comms protocol compatibility

• Earthing and bonding

• Sun shading of critical equipment

• Hazardous area compatibility

• Electrical protection and discrimination

• Specialist commissioning requirements

• Maintenance routines and operations procedures

Cables to motors, starters, switchgear, heaters are normally routed direct to skid equipment. All

termination and interface points shall be identified.






Each motor shall be provided with a Remote Control Unit (RCU) in the field near the motor for emergency

stopping purposes. This shall be provided by engineering contractor where it is not part of packaged

equipment design. Based on the control requirements, there may also be a requirement for local

start/stop push button, ammeter, auto/manual and local/remote selector switches, etc. Motors installed atelevated platforms shall be provided with additional RCU at ground level for stopping the motor.

Adequate interface information shall be included within engineering designs consistent with the above

(including drawing references etc.). The wholesale repeat of vendor design data on engineering design

contractor drawings shall be avoided. The vendor drawings and documents shall be included within work

packages where necessary and available.

4.5. ESP’s and Var i ab le Speed Dr iv es

General

There is a growing (industry wide) use of electric submersible pumps (ESP’s) for oil and water artificial lift.This means there are an increasingly diverse choice of equipment and technologies available both for

surface and downhole facilities. Engineering considerations to take into account when designing these

systems include:

• Minimizing the equipment requirements (and hence footprint) of surface facilities

• Provision of maximum future flexibility (as reservoir conditions can vary)

• Measures to ensure a reliable run life of downhole equipment

• Keeping system harmonics to a minimum (important when large loads are considered)

This BoD makes reference to equipment available at the time of writing and shall be considered togetherwith technology developments. A typical ESP installation will include permutations of the following:

Step Down Transformer

HV systems are normally transformed to LV due to limitations within the power electronics. Usually, there

are two secondary windings which provide a phase shift for a 12 pulse converter, thereby reducing

harmonics. These secondary windings can supply several ESP's with multiple converters via star-delta

distribution switchboards or directly supply a larger converter controlling a single ESP.

An alternative transformer configuration has multi-tap phase shifted secondary windings which can supply

up to four smaller ESP’s. This has the added advantage of eliminating the requirement for star-delta

distribution switchboards. It can also permit the use of 6 pulse converters, with harmonic cancellationthrough phase shifted secondary windings.

Variable Speed Drive

Variable speed drive power converters offer design and operational flexibility when compared to soft start

units. The drive frequency (and consequently power output) is variable over a wide range & this is an

advantage as downhole conditions can vary. The frequency ramp up control facility of a VSD offers a

soft-start capability.

These units are available in a number of ratings and configurations for both indoor and outdoor

applications. Indoor units offer space saving advantages over outdoor units but air conditioning

requirements due to heat dissipation can be significant. Protection and monitoring systems for ESP’s are






normally included within the VSD and typically includes motor protection, current monitoring, winding

temperature, fluid temperature, etc.

The equipment shall be specified and configured for remote start, interfacing with DCS system (refer to

section 2.5). Remote start is particularly relevant where equipment is located on remote unmanned

facilities accessible only by boat or helicopter.

The input voltage ratings are typically 380V or 480V AC. Input voltages of 415V are available but with a

corresponding reduction in power output.

Technology within this area is changing and some manufacturers now offer a VSD with HV power

electronics, thus eliminating the requirement for a step down transformer.

Soft-Start Unit

There can be space and cost saving advantages by using soft starters in place of VSD’s. However this

has to be balanced against operational inflexibility once installed. Voltage depression studies based uponmotor characteristics may be required in such applications.

Direct on Line Starter

In some applications, direct on line starting can be considered as an option (and would eliminate the VSD

or soft-start unit). The use of DOL starting imposes additional stresses on downhole ESP’s (particularly

cable insulation) and for this reason equipment run life considerations require to be formalized with

manufacturer before DOL starting can be considered. DOL starting also has the same operational

inflexibility of soft-start units. Voltage depression studies based upon motor characteristics may be

required in such applications.

Step-up Transformer

The output from the VSD or soft start unit is transformed to HV to suit the requirements of the ESP

through the step up transformer.

Harmonic Filters

Where large non linear loads are proposed, consideration shall be given to the effects of harmonics on

the electrical system. Where studies confirm the requirement, passive or active harmonic suppression

shall be installed. Harmonic filters shall be connected as close as possible to source of harmonics.

Electric Submersible Pumps (ESP)

The detailed specification of ESP’s is outside the scope of this BoD. Within OPQL, this is normally

completed by (or in conjunction with) the artificial lift specialist. Close coordination is required however to

ensure that electrical and control interfaces are adequately specified and designed. Project testing and

documentation requirements shall be clearly defined at the outset and identified on SDRL.

The Manufacturer shall be required to supply calculated rotor responses, lubrication requirements, ramp

times, and the transient air gap torques with their duration in case of 2 and 3 phase short circuits on the

motor terminals. Where specified, the Manufacturer shall be quote a torsional vibration analysis as a

separate item. The Principal may request this study to be performed in addition to that performed by the

driven equipment Manufacturer. In such event, the results shall be acceptable to all parties involved.

Coiled Tubing Deployed ESP’s

Coiled tubing deployed ESP’s have a different pump string configuration (the pump is at the bottom) and

production is through the annulus and not the tubing. With the exception of the wellhead outlet there is






no significant difference however between surface equipment used for coiled tubing deployed or

conventional ESP’s.

Location of Equipment

Historically, OPQL have installed VSD’s as packaged equipment, normally on remote platforms in close

proximity to the wellhead. Industry experience has confirmed the acceptability of installing the VSD

remote from the wellhead (in extreme cases, several kilometres distant). Future ESP installation

campaigns shall consider the possibility of installing the VSD on central manned facilities (for example

PS1), with the ESP supplied via subsea power cable. Where such installations are proposed,

consideration shall be given to utilizing a suitably specified downhole cable instead of a conventional

subsea cable. Potentially, there are considerable maintainability, operability and economic advantages

with such an installation.

The inclusion of equivalent subsea/downhole cable impedance may be required together with a detailed

Factory Acceptance “String Test” when innovative installation techniques are considered (such as remoteinstallation of VSD’s).

4.6 . Swi tchro oms, Equ ipment Rooms, Bat te ry and P lan t Rooms

General

The design of equipment and plant rooms shall always pay due regard to their intended use and whether

these are manned or normally unmanned areas. This to include safe and satisfactory access

arrangements to equipment for operational and maintenance purposes. Manual handling requirements

shall be taken into account. Refer to section 4.7 for HVAC design requirements.

Satisfactory access and egress requirements shall be provided. In most cases this will require theprovision of two means of escape.

Switchrooms and Equipment Rooms

These shall be located in non-hazardous areas and preferably near the equipment they are provided for.

In exceptional cases, equipment rooms may be located in a hazardous area classified as Zone-2 subject

to approval by OPQL TA. The following requirements shall apply:

• The interior of the sub-station shall be pressurised in accordance with IEC 60079

• An over-pressure of at least 0.5 mbar shall be maintained using a duplicate fan system with a

suitable dry-type dust filtering system to ensure a supply of clean air, each fan system being

capable of supplying the required pressure. The air shall be taken from non hazardous area.

• The fan systems shall be suitable for a Zone-1 area and shall be supplied from two different and

independent sources of electricity supply

• Both fans shall be normally in operation with individual alarms to indicate failure in a manned

control centre

In all cases, for reasons of reliability and serviceability, the electrical switchgear installations including

batteries shall be located indoors in allocated buildings provided with HVAC system.

All rooms containing switchgear shall have two access doors to allow personnel and the largest

equipment to pass in to or out of the room. Safety and escape routes shall be provided all around






switchgear where personnel may need to operate or maintain the equipment. Such routes shall have two

clear and unobstructed paths to a door. All doors shall be dust tight and weatherproof.

33 kV switchgear shall be located in a separate room. Access to this room shall be through a lockable

door.

Switchrooms and local equipment rooms shall be provided with portable wall mounted rechargeable

hand-lamps. These shall be plug-in type complete with fixed charging units and rechargeable batteries

and be suitable for hazardous area (Zone-1) use. These shall be located near the entrances.

New switchroom and equipment plant rooms shall be fitted with ceiling grid support systems. These shall

be selected from Oglaend, Norway product range (or approved equivalents).

Fire and smoke detection system shall be provided throughout the sub-station building. A weatherproof

fire alarm pushbutton shall be located on the external wall adjacent to the main personnel access door.

Portable fire extinguishers shall be provided inside the sub-station, in each separate room. They shallhave an extinguishing medium that is fully compatible with the electrical and electronic equipment in the

station. Instruction charts should be fitted on the wall adjacent to each extinguisher. Each sub-station

shall be provided with the following minimum items:

• Fire extinguishers

• Fire blankets

• First aid kit and instruction plate

• Escape lights and emergency exit signs

•

No smoking sign

• Vertical drawing rack

• White board

• Framed single line diagrams

• Telephone

• Tools and spares cabinet

• Key box

Rubber matting shall be provided in front of HV and LV switchboards. The matting shall be minimum

650V grade tested to 15000V and shall be of black colour and with non-slip finish.

The construction of sub-station building and the material used shall be such that propagation of fire

through the building is minimal. The fire rating of the sub-station building shall be as per QP Corporate

Philosophy for Fire and Safety QP-PHL-S-001.

Each sub-station shall be suitably identified with warning plates shall be provided at the outside of the

building. New sub-stations shall make provision for extension of switchboards by an additional 2 cubicles

at each end without compromise to equipment access or escape routes.

Equipment access ways shall be provided front and rear 1m minimum after considering wall mounted

distribution boards, interposing relay panels etc. There shall be sufficient space at front of switchgear

panels to manoeuvre circuit breaker handling trucks without blocking emergency access routes.






Battery Rooms

Separate battery rooms shall normally be provided for housing UPS system batteries. It is acceptable to

locate switchgear tripping and closing batteries within the switchroom. In such event, the batteries shall

be fully enclosed within ventilated panels. The HVAC requirements shall ensure adequate air dilution

avoiding a build up of hazardous gases (proven buy calculation). A direct link to air extraction system is

preferred. Where dedicated fans are provided, they shall be fitted with fan failure detection. Refer to

section 4.7 for battery room HVAC design requirements.

Battery rooms shall normally be accessed from outside of the switchroom. Manual handling requirements

in particular require consideration, noting that the weight of some batteries will require simultaneous

access by two persons for removal/installation. It is recommended that the room size is adequate to

allow access to at least three sides of each battery bank for maintenance purposes.

A water tap, wash-basin, eye-wash facility, sink and drain shall be installed in the room. The floor and

walls (up to 2m height) shall be provided with acid resistant tiles. All electrical equipment in the batteryroom e.g. lighting fixtures, exhaust fans, convenience outlets, fire and gas detectors etc. shall be suitable

for hazardous area classification Zone-1, Apparatus Group IIC. Battery isolation devices shall be

provided.

Onshore Indoor Sub-stations

The land-based sub-stations shall normally be designed as elevated structures sitting on a minimum

number of reinforced concrete legs. These shall contain switchgear, UPS systems, batteries, annunciator

panels, fire detection and fire fighting equipment, HVAC system, power management system equipment,

etc. Transformers are normally located in an adjacent lockable fenced area in transformer bays. A

typical sub-station layout for raised sub-stations is provided on QP Engineering Standard Drawing

ES.2.68.0001. A more detailed specification of onshore outdoor substations is outside the scope of this

BoD. Refer to ES.2.03.0001 for guidance concerning this if required.

Package Sub-stations

Package sub-stations may be used for temporary installations but only in very special cases can these be

considered for permanent installations. Package sub-station shall be supplied as complete factory

assembled and tested transportable units. HVAC systems shall be provided for package sub-stations in

accordance with section 4.7 HVAC requirements.

The HV switchgear, oil-filled transformer and LV switchgear shall be located in separate compartments

each accessible from the outside by lockable doors. Dry-type transformer can be located in the same

compartment having the LV switchgear. Sufficient space shall be available in the compartments fortermination of cables and safe operation of the switchgear. The ingress protection of the compartments

housing the switchgear shall be minimum IP 55 as per IEC 60529. The compartment having the oil-filled

transformer shall be equipped with leak-proof oil containment area. Each compartment shall be provided

with lighting fixtures and convenience outlets of the weatherproof and industrial type.

4.7. HVAC Requi rements

The HVAC equipment requirements shall be identified and specified by engineering contractor within a

functional requirements specification and associated data sheets.






Due regard shall be taken of the intended use of the area served as this will have a significant effect on

the cooling and ventilation requirements, i.e.:

• Manned (or unmanned)

• Installed equipment criticality

• Battery rooms

• General (normally unmanned) plant rooms

Equipment specifications shall include a clause excluding the use of Ozone depleting refrigerants.

Standard industrial HVAC equipment should be used wherever it is feasible to do so. HVAC systems can

be specified as supplied by manufacturers as single components or integrated into packaged units.

Measures shall be taken to avoid damage due to chilled water leakage. Under no circumstances shall

chilled water lines be routed through equipment rooms.

The temperature of rooms which are continuously occupied shall be maintained between 20 and 25°C,

(controlled within +/-1°C, set point typically 21°C) and a relative humidity between 20 and 70% (controlled

within +/-10%, set point typically 50%). The temperature of unmanned plant rooms should not exceed

25°C after taking equipment heat gains into account.

Ingress and distribution of dust particles in plant buildings shall be avoided by sealing of doors and

incorporation of filters into air handling units and all air intakes.

HVAC calculations should be based on heat gain from all sources such as personnel, electronic

equipment, lighting, fresh air intake, walls, roofs, dehumidification losses, windows etc. The heat gain

from electronic equipment requires special attention and shall be based on data provided by the

equipment suppliers. Where necessary, provisional; data can be used with adequate contingencies. The

design contractor shall calculate the necessary minimum number of air-changes per hour that are needed

to regulate the room temperature and to remove the dissipated heat.

Fresh air ventilation may be required in order to provide the specified minimum number of air-changes or

to maintain an over-pressure in order to prevent the ingress of hazardous atmospheres. Overpressure

relief dampers or other measures to equalize air pressure should be considered within the design.

A ventilation system with 100% redundancy (positive exhaust type) shall be provided in battery rooms for

diluting the concentration of hydrogen present in the room by exhausting it to the outside of the room.

The ventilation flow rate within battery rooms shall be adequate to maintain dilution of hydrogen from

batteries to within safe levels under boost charge conditions. Interlocking to inhibit boost/quick charging

on failure of ventilation system shall be provided. Air-conditioning ducts shall be located near the floor.

The fresh air ventilation fans shall be provided with adequate air filters. Redundancy (e.g. double fans)

should be provided. They shall be suitably located to provide adequate dilution of the total space. The

extraction system shall operate satisfactorily in wind conditions varying from still air to design wind

speeds.

Noise limits directly or indirectly caused by HVAC equipment shall be specified within the functional

design specification and measures taken to keep within these limits.

The HVAC system design shall cater for abnormal conditions. The required working conditions for the

equipment shall be ensured during abnormal conditions. All HVAC equipment shall be backed up (within

reasonable limits). Equipment rooms with critical heat sensitive equipment shall have 100% redundancy

of HVAC equipment.






HVAC electrical equipment shall be suitable for the applicable hazardous area. It should be noted that

installation of equipment rooms within hazardous areas shall be avoided wherever possible.

HVAC vendor control and alarm systems are normally acceptable and shall include temperature and

humidity control for each working area. Control systems shall normally operate in automatic mode but

manual operation shall be possible.

HVAC alarms shall be individually displayed on local HVAC panels. Common HVAC alarm signals

generated by the HVAC control system shall be routed to DCS system. Microprocessor-based control

systems such as Programmable Logic Controllers (PLC’s) should be used.

For buildings containing both the control room(s) and administration offices, the integration of HVAC

control systems and the Building Automation System shall be considered.

4.8 . Temporary ins t a l la t ions

Temporary installations are installations which are installed for a short duration (typically 3 months or

less), normally to satisfy an urgent operational requirement or to assist with construction of permanent

facilities. Many temporary facilities ultimately remain in service for much longer than the original intended

service life.

Unless otherwise agreed with OPQL TA, temporary facilities shall be engineered and installed in full

compliance with this BoD as per permanent facilities.






5. DOCUMENTS AND DRAWINGS

All necessary drawings required for the design of electrical system, installation of equipment and theinterconnection of equipment, cables, and wires shall form part of the design. Such information shall be

updated when alterations to the design are made and shall include additional information that is required

during erection or may be required for future maintenance, troubleshooting and operation.

Only certain categories of documentation are maintained by OPQL as key field technical information.

OPQL core drawings are defined in document FAC 226 (OPQL Key Drawing Change Procedure).

Refer also to Appendix G for a list of core drawings. Wherever possible, engineering contractor design

drawings shall be based upon these core documents, backed by additional drawings where required.

Drawings and technical documentation shall be prepared using OPQL standard formats and templates.

These are available from OPQL DCC on request. Please refer to OPQL TA for guidance if any doubt

exists. Standard formats exist for the following documents:

• Switchgear GA’s, SLD’s, interconnection and block diagrams

• Distribution board schedules

• Protection setting schedules

• Lighting & small power layouts

• Earthing details

Equipment vendors shall be responsible for providing all documentation in accordance with FAC-229

“Instructions to Sellers” and the Seller Document Requirement List (SDRL) supplied by the Purchaser. Alldocumentation shall be forwarded to Purchaser’s nominated address.

Review documentation should normally be issued in electronic (PDF) format via OPQL and contractor

DCC. Final documentation shall be issued in PDF and native file format.






APPENDICES

A Definition of Terms and abbreviations

B Approved Codes Standards and Specifications

C Electrical Bulk Materials and Minor Equipment

D Earthing and Bonding

E Recommended Illumination Levels

F Example Format – Planned Maintenance Routine

G Facilities Key Records Library

H Electrical Construction and Commissioning Checklists

J IEC 60092-352 Current Capacities and Defined Installations






APPENDIX A – Def i n i t i on o f Terms and Abbrev i at i o ns

Definition of Terms

The technical definition of the electrical terms/words shall generally be as per IEC 60050 unless

otherwise defined within this document and below:

Pre-Commissioning

This shall be taken to mean functional tests of equipment (such as protection relay injection tests etc.)

and equipment energisation. All vendor and installation checks and tests are completed sufficient to

ensure equipment is ready to handover for operational trials.

Commissioning

This shall be taken to mean energisation and the final tests and checks at OPQL facilities site subsequentto the energisation necessary to ensure that each circuit satisfactorily performs its function. These tests

will include interface checks across inter-related systems and 4 hr run tests on motors etc. For smaller

projects, equipment can be handed over to operational use after commissioning. Larger projects will

require integrated performance trials.

Plant Start-up

Larger projects have more complex operational performance tests that are required subsequent to

commissioning of individual and inter-related systems.

Contractor

Is the party which carries out all aspects or part of the design, engineering, procurement, construction andcommissioning of the plant.

Inspection

This shall be taken to mean a visual inspection of the equipment/installation.

Manufacturer

Is the party that manufactures equipment and services to perform the duties specified.

Shall

The word 'shall' is to be understood as mandatory.

Should

The word 'should' is to be understood as being strongly recommended.

Supplier

Is the party that supplies equipment and services to perform the duties specified.

Testing

This shall be taken to mean the performance, routine and special tests normally carried out at the factory

of the manufacturer.






Autonomy (of a battery)

The duration for which the battery can supply its rated load within its specified voltage limits, following a

prolonged period of battery float charge operation.

Certificate

Document issued by a recognised authority certifying that it has examined a certain type of apparatus

and, if necessary, has tested it and concluded that the apparatus complies with the relevant standards for

such apparatus.

Certificate of conformity

Document issued by a testing station and approved by a national or other appropriate authority, stating

that a prototype or test sample and its specification have a level of safety equivalent to that of an

electrical apparatus for potentially explosive atmospheres which complies with the requirements of one or

more types of protection as laid down in a national or international standard.

Certified electrical apparatus

Electrical apparatus for which a certificate of conformity or a certificate of inspection has been issued.

This is usually (but not exclusively) applied to hazardous area equipment.

Declaration of conformi ty

Document issued by the manufacturer stating that the electrical apparatus complies with the requirements

of one or more types of protection for use solely in locations where the danger is limited and the electrical

apparatus complies with the requirements of national or international standard.

Vital Service

This is a service which, when failing in operation or when failing if called upon, can cause an unsafe

condition of the installation, jeopardise life or cause major damage to the installation.

Electrical power system

All installations and plant provided for the purpose of generation, transmitting and distributing electricity.

Emergency light ing

Lighting provided for use when the supply to the normal lighting fails.

Escape lighting

That part of emergency lighting which is provided to ensure that an escape route is illuminated at all time.

Power management system

A computerised system that is dedicated to monitoring and controlling defined aspects of an electrical

system.

Remote Control Unit (RCU)

A field mounted control device in the vicinity of a motor/consumer for operation of the remotely installed

control gear of the consumer.

ATEX

An abbreviation from the French title of the 94/9/EC directive “Appareils destinés à être utilisés en ATmosphères Explosibles”.






As of July 2006, organizations in EU must follow the directives to protect employees from explosion risk inareas with an explosive atmosphere. There are two ATEX directives (one for the manufacturer and onefor the user of the equipment):

• ATEX 95 equipment directive 94/9/EC, Equipment and protective systems intended for use inpotentially explosive atmospheres;

• ATEX 137 workplace directive 99/92/EC, Minimum requirements for improving the safety andhealth protection of workers potentially at risk from explosive atmospheres.

Hazardous Area

Areas where hazardous explosive atmospheres may occur are classified into zones depending upon thelikelihood of an explosive atmosphere occurring and its persistence if it does.

TN-S

An electrical system with separate neutral and protective (earthing) conductors throughout the system.

Definition of Abbreviations

AFC Approved for Construction

DCC Document Control Centre

FAC Facilities Engineering and Construction

FTI Facilities Technical Information

HES Health, Environment and Safety

OPQL Occidental Petroleum Qatar Ltd

PHR Process Hazard Review

PRM Process Risk Management

QA Quality Assurance

QC Quality Control

STOMP Spares, Training, Operating and Maintenance Procedures

DCN Drawing Change Notice EQ Engineering Query FAC Facilities Engineering and Construction MOC Management of Change

PMR Planned Maintenance Routine

PSICR Programmable Systems/ Information Change Request

PTW Permit to Work

RfC Request for Change

DPSA Development and Production Sharing Agreement

SCENR Supreme Council for the Environment and Natural ReservesQGOSM Qatar General Organization for Standards and Metrology

OOGC Occidental Oil and Gas Corporation

IEC International Electro technical Commission

BSI British Standards Institution

CAA Civil Aviation Authority

VSD Variable Speed Drive

ESP Electrical Submersible Pump

UPS Uninterruptible Power System

TA Technical Authority

SAFOP Safety and Operability Studies

SoR Statement of Requirement

HAZOP Hazard and Operability StudiesHVAC Heating, Ventilating and Air Conditioning






RCU Field mounted (motor/consumer) control device

PMS Power Management System

HV High Voltage - a voltage exceeding 1000V ac

LV Low Voltage - a voltage up to 1000V ac

RCCB Residual current circuit breaker






APPENDIX B – App ro ved Codes , Standards and Sp ec i f i cat i ons

The following list are the recommended codes, standards and specifications to be used for electricalengineering design specification and procurement activities on OPQL managed facilities in Qatar. Where

more than one standard exists, only the most relevant document (either QP or OPQL originated) is listed.

Project specific documents are included where no suitable company specification exists. Please refer to

OPQL TA for guidance for any subject areas not adequately covered by these standards.

The user’s attention is drawn to section 2 of this document which gives guidance on application of these

codes and standards, and precedence clauses to be used for reconciling conflicts between documents.

Prior to use, the user shall ascertain the latest revisions of these documents. This information is readily

available from OPQL Documents and Standards section.

These documents have been categorised into 3 groups as follows:

Cat 1: Reference standard for subject area. The document shall be applied in its entirety.

Cat 2: Reference standard for subject area. The document is directly applicable to the subject area

but there are exceptions. Refer to clarification within this BoD or OPQL TA as necessary.

Cat 3: The document is to be used for general guidance but engineering judgement will be required

as there are many exceptions. The document is either project specific or included for reference because

there are no other relevant company standards. Refer to clarification within this BoD or OPQL TA as

necessary.

RECOMMENDED CODES and STANDARDS FOR USE ON OPQL MANAGED FACILITIES

DOCUMENT NUMBER DESCRIPTION CATEGORY

OPQL DOCUMENTS

000000-4-XPS1-BD-0001-001 Electrical Basis of Design 1

000000-5-XPS1-BD-0002-001 Instrumentation Basis of Design 1

000000-4-XPS1-SP-0001-001 General Cable Specification 1

000000-4-XPS1-29-682-001 Primary Earthing System 1

000000-4-XPS1-21-6820-001 Secondary Earthing System 1

E250 to E343 inclusive Electrical construction and commissioning checklists 2000000-8-YPS1-PR-00001-001 Project Document numbering format 1

000000-8-XPS1-TD-0001-001 OPQL Technical Authorities Manual 1

000000-8-XPS1-TN-0003-001Certification Matrix and Requirements Summary forMaterial Requisition

1

000000-8-XSP1-SD-0001-001 State of Qatar Environmental Protection Standards 1

YPS1-4-SP-6923-001 ISND Phase 3 Subsea Cable Specification 2

YPS1-4-CA-6924-001 Calculation example – Subsea cable length 2

YPS1-4-CA-6921-001 LV Cable Sizing 2

YPS1-4-TN-6921-001 Hazardous Area Classification Technical Note 2

YPS1-4-SP-6928-001 Safety and Operability Review (SAFOP) Terms ofReference

2







DOCUMENT NUMBER DESCRIPTION CATEGORYYPS1-4-SP-6922-001 ESP Package Specification 3

YPS1-4-DS-6921-001 ESP Transformer Data Sheet 3

YPS1-4-DS-6922-001 ESP Soft Starter Data Sheet 3

YPS1-4-DS-6923-001 ESP Motor Data Sheet 3

YPS1-4-DS-6925-001 ESP Junction Box Data Sheet 2

YPS1-4-SP-6927-001 Marine Navigational Aids Specification 3

YPS1-4-SP-6928-001 RMU Specification 2

YPS1-4-TN-6920-001 Comparison of HV Switchgear vs Ring Main Units 2

403086-4-PS1E-SP-0002-001

OPQL Specification for Power Management

Systems 3

410426-4-PS1E-SP-0001-001 Specification for Replacement HV Switchgear 3

410924-8-PS1E-MR-0001-001 Glycol Reboiler Requisition 3

410924-8-PS1E-SP-0001-001 Glycol Reboiler Electric Heater Skid 3

PRD 500 Electrical Safety Guidelines 1

DEV-201 Facilities Engineering and Construction Policy 1

FAC-219 Commissioning Procedure 1

FAC-223 Engineering and Procurement Procedures 1

FAC-225 Engineering Closeout Procedure 1

FAC-226 Key Drawing Change Procedure 1FAC-227 Document Control Procedure 1

FAC-228 Drawing Office Procedure 1

FAC-229 Instructions to Sellers 1

FAC-230 Instructions to Contractors 1

PRM-PY-001 Process Risk Management Policy 1

PRM-PR-001 Facilities Technical Information 1

PRM-PR-002 Process Hazard Review and Risk Assessment 1

PRM-PR-002-MATRIX OPQL Risk Matrix 1

PRM-PR-003 Management of Change 1PRM-PR-004 Operating, Maintenance Procedures 1

PRM-PR-005 Mechanical Integrity and Quality Assurance 1

PRM-PR-006 Pre-Start up Safety Review 1

HES-027 Lifting Equipment Control and Operations Policy 1

402160-4-PS1K-BD-6015-001 PS1K Electrical Design Basis 2

402160-4-PS1K-SP-6063-001 PS1K Electrical Package Specification 3

400060-4-HALU-6593 PWHF Electrical Philosophy Document 2

Al Morjan BoD Section 8 Electrical Design Basis 2

410641-4-PS1R-SP-0001-001 Distribution board specification 3

410641-4-PS1R-DS-0001-001 Distribution board data sheets 3







DOCUMENT NUMBER DESCRIPTION CATEGORYQP DOCUMENTS

EFS.00.08.03 Offshore Environmental Conditions 1

EFS.00.08.04Specification for Equipment Preservation, Protectionand Packaging

2

EFS.00.08.05 QP General Specification for Packaged Units 2

QP-SPC-L-002QP Technical Specification for Painting andWrapping of Metal Surfaces

2

QP-PHL-S-001 QP Corporate Philosophy for Fire and Safety 2

QP-STD-ENV-005 QP Environmental Standard for Legal Requirements 1

ES.D.10 Engineering Standards - Draughting 2

ES.2.06.0001 Electrical Installation Recommended Practices 2

ES.2.14.0001 HV GT Driven Synchronous Generators 2

ES.2.14.0002 Diesel Engine Driven Generators 2

ES.2.14.0010 HV Switchgear and Controlgear for Use Indoors 2

ES.2.14.0015 LV Switchgear and Controlgear for Use Indoors 2

ES.2.14.0019 Busbar Ducting 2

ES.2.14.0020 HV Liquid Filled Transformers 2

ES.2.14.0022 Dry Type Power Transformers 2

ES.2.14.0030 HV Cage Induction Motors and Synch Motors 2

ES.2.14.0035 LV Cage Induction Motors 2

ES.2.14.0036 Electric MOV Actuators 2

ES.2.14.0040 AC UPS Systems 2

ES.2.14.0044 DC UPS Systems 2

ES.2.14.0045 Cathodic Protection Facilities for Offshore Facilities 2

ES.2.14.0060 Secondary Selective System 2

ES.2.14.0065 Power Management System 3

ES.2.14.0085 Neutral Earthing Resistors 2

ES.2.14.0095 Power System Studies 3

ES.2.14.0098 Electrical Requirements for Package Equipment 3

ES.2.50.0001 DC UPS System Key Single Line Diagram 2

ES.2.53.0001 DOL Starter up to 3.7kW 2

ES.2.53.0002 DOL Starter above 3.7kW up to 55kW 2

ES.2.53.0011 Switch Fuse Feeder 2

ES.2.53.0012 Switch Fuse and Contactor Feeder 2

ES.2.53.0013 PEC Controlled Lighting Feeder 2

ES.2.53.0014 Contactor Feeder for Heaters 2

ES.2.13.0044 Data sheets - DC UPS Systems 3

ES.2.03.0001 QP Electrical Engineering Philosophy 3






APPENDIX C – Elec t r i c al Bu l k Mater i al s and Mino r Equ i pm en t

General

Due regard shall be taken during engineering design and selection of equipment to ensure compatibility

between new and existing systems. The following outline specification of bulk items and minor equipment

is compatible with equipment installed on PS-1 facilities and typical of equipment on other OPQL

managed facilities. This is not an exhaustive listing. For minor projects equipment should be selected

from the attached listing. For larger projects, economic considerations will prevail, however compatibility

and standardisation should also be taken into account. Please refer to OPQL TA for guidance as

necessary.

Operating voltages shall be specified suitable for the electrical system of use.

Specifications for Electrical Bulk Materials and Minor Equipment

Fluorescent Fixtures

The fittings shall be suitable for Zone-1, IIB, T3 and the Make of the EX fluorescent fitting shall be

CEAG or approved equivalent as follows:

• 2ft normal light fitting CEAG type eLLK 92018/18

• 4ft normal light fitting CEAG type eLLK 92036/36

• 2ft emergency light fitting with back up battery of 3 hours: CEAG type eLLK 92018/18 NIB

• 4ft emergency light fitting with back up battery of 3 hours: CEAG type eLLK 92036/36 NIB

Battery room lighting shall be suitable for Zone-1, IIC or IIB+H2.

Floodlights – Ex 'D’

Floodlights shall be suitable for offshore marine use. They shall be IP 66/67 rated, 250W, EEXde IIC

T3 at 55C type. The make shall be Chalmit or a pre-approved equivalent.

Junction Boxes

All outdoor Junction Boxes (JB’s) including lighting JB’s shall be fully weatherproof and dust proof (IP-

66 minimum), corrosion resistant suitable for use in Zone-1 certified Ex ’e’, Gas group IIB,

Temperature Class T3. Enclosure material shall be GRP (UV and Hydrocarbon resistant) or 316L

stainless steel and provided with 6mm² size external 316L stainless steel earth screw and internal

metallic back plate with earthing point. Junction boxes shall have external fixing lugs. Operating

voltages shall be suitable for the electrical system of use.

Cable entries and terminals (SAK type polyamide) shall be sized based on cable sizes specified in the

requisition.

Cable entry shall be from bottom only, top side entry shall be avoided and all entries shall be ISO

metric threaded. The material shall be of high mechanical and thermal strength, UV resistant. The

material shall be anti-static and anti-magnetic.






All accessories such as bolts, nuts etc. shall be 316L stainless steel. Junction Boxes shall be provided

complete with terminals, mounting rails, end plates/partition plate, marking strips/tags, etc and clear

PVC protective covers with danger voltage labels.

Outside identification plates shall be corrosion proof by nature (stainless steel) and securely fixed to

enclosure (not glued or Aluminium riveted) by stainless steel screws / PVC rivets.

The make shall be Abtech, CEAG, Klippon, Hawke or pre-approved equivalent.

Cable Trays and Ladder Racks

ALL cable ladder rack, cable tray, covers, bends, tees and all ancillaries shall be manufactured from

an industry accepted pultruded glass reinforced plastic (GRP), complete with UV veil, from MITA or

pre-approved equivalent GRP products. Cable Tray shall be MITA Fibatray GF series (or equivalent).

Cable Ladder Racks shall be MITA Fibarack “GN” Heavy Duty Series (or equivalent). Accessories

and fittings such as bends, risers, tees, crosses, reducers, etc. shall be fabricated from the samematerial of cable trays/ladders as a single piece construction. The trays and bends etc. shall be

perforated and ventilated with the holes occupying 30% or more of the tray area. This is required to

satisfy “freely ventilated” criteria as detailed within IEC 60092, Annex A, Installation methods E or F.

The fixing accessories such as nuts, bolts and fasteners shall be supplied by the vendor.

Remote Control Units

All Remote Control Units (RCU’s) will be field installed near the respective motors. The RCU shall be

Ex-d / Ex-e ATEX certified type construction suitable for Zone-1 or Zone-2, Gas group IIB,

Temperature T3 environnemental conditions, IP 66. The make shall be CEAG or MEDC, or pre-

approved equivalent.

Convenience Socket/Welding Socket Outlets

Convenience socket outlets and welding socket outlets shall be EEx d, IIB, T3 certified for use in

Zone-1 areas. All socket outlets shall have ingress protection of IP 66.

Each convenience outlet/welding circuit shall be protected by phase short circuit protective devices

and by current-operated earth leakage protective devices/residual current device (RCD). The

sensitivity of RCD shall be 100mA for single phase convenience outlets and 300mA for welding

socket. The operating time shall be less than 30 msec. The rating and make of the sockets shall be as

follows:

• 110V AC socket outlet: STAHL, P/N 8575/11-304 (16 Amps, 2P+E , EEXde IIC T6)

• 240V AC: STAHL, P/N 8575/11-306 (16 Amps, 2P+E , EEXde IIC T6)

• Welding Sockets: ABB type GHG 534 1506 VO (63Amps, 3P+N+E, EEXde IIC T6)

Cable Glands

Cable glands shall be manufactured to BS 6121. Make shall be CMP/HAWKE/Cooper or pre-

approved equivalent. Cables glands shall be explosion proof suitable for use in Zone-1, Gas groups

IIB, temperature class T3 and shall be certified EEx “de” in accordance with CENELEC Standards EN

50018/50019. The certification shall be by an internationally recognised authority like BASEEFA.






However, certification from other recognised authorities such as FM, PTB, etc. shall be considered

subject to purchaser’s approval.

Cable glands shall meet the requirements of IP-66 (minimum) double sealing universal type forsuitable weather protection, in accordance with IEC-60529.

Cable glands shall be of double compression type and shall be Nickel plated brass. Cable glands

shall have ISO metric threads, deluge proof without PVC shrouds. Cable glands shall be

manufactured to provide cable sealing of inner and outer sheaths and mitigate cold flow potential of

outer sheath. Clamping of armour by special ring. Cable glands shall be provided with earth tag, lock

nut, serrated washer and nylon IP sealing washer (not the Red moisture absorbent fibre type). Cable

glands for single core cables shall be connected to non-magnetic non-ferrous gland plates. Cable

entry adaptor and reducer shall be Exde nickel platted brass

Cable Lugs

Crimping type cable lugs of appropriate size suitable for the core cross-section (Power and Control),

as required shall be provided from Bicon or approved make. Necessary sleeving shall be provided

over the lugs using either HELLIMAN RUBBER or HEAT SHRINK SLEEVE.

Cable Terminations

Conductors shall be fitted with approved pre-insulated crimped pins for connection into clamp type

terminals or fitted with crimp lugs for stud terminals. Lugs shall either be pre-insulated or heat shrink

shrouds shall be fitted to un-insulated lugs. Cable terminations shall be of solder less crimped design

to suit the particular equipment and shall be tin plated copper lugs.

HV Cable Termination Kits / Jointing Kits

HV cable joints should be avoided wherever possible. Where unavoidable, HV termination kits shall

be suitable for specified size, voltage rating, and type of the Cables and suitable for the hazardous

area classification (Zone-1, IIB, T3). Elastimold/Raychem Heat shrinkable, stress relieving type

termination kits shall be used for HV cable termination.

The termination kits shall contain all accessories that are required for completing the end termination

at switchgear, transformer, well head JB etc. Any items/components/accessories that are not

specifically mentioned but are required for making the Elastimold/Heat shrinkable type termination

complete, shall be considered and supplied along with the termination kits.

HV Terminations

HV cable end termination kits shall be of heat shrink type Raychem (or equivalent) make suitable for

the type of cables indicated on cable specification or datasheet. The end termination kits shall be

complete with all standard accessories including heat shrink stress relieving sleeves, trifurcating glove,

solder less earth spring coils, drain wire and installation instructions etc.

Lighting and Small Power Switches

Switching of lighting etc. is normally done from distribution boards. Exceptionally, where required,

on/off switches shall be double pole, suitably rated, 240V, 50Hz, and suitable for outdoor installation.

Typically CEAG or MEDC supply.






Enclosures shall be certified for Ex-d/Ex-e type construction suitable for Zone-1, Gas group IIB,

Temperature T3 environmental conditions, IP 66/67. They shall typically be provided with a 6mm² size

external earth screw/stud. The switch/enclosure shall be moisture resistant and fungus proof resistant

to salty weather condition, UV resistant and hydrocarbon resistant, corrosion and ambient environmentas specified. Small Power Switches shall be as follows:

• 240V,1ph, 10A, 50Hz, switched socket outlet with interlocked switched suitable for Zone-1,

IIB, T3.

• 240 V,1ph, 10A, 50Hz, switched socket outlets suitable for Zone-1, IIB, T3.

• 415V, 3ph+N, 63A, 50Hz, welding outlet, suitable for Zone-1, IIB, T3.

Wellhead Junction Boxes

High Voltage (3.3kV or 6.6kV) outdoor well head junction boxes shall be fully weatherproof and dustproof (IP-66 minimum), corrosion resistant stainless steel 316L, suitable for use in Zone-1 certified Ex

’e’, Gas group IIB, Temperature Class T3 application. Make shall be ABTECH or pre-approved

equivalent.

Multicable Transits

Multi Cable Transit MCT frames shall be type suitably sized in every aspect, with a generous

allowance for future cables (typically 50% minimum). The make shall be Roxtec or HAWKE or Oxy

approved equivalent.

PA/GA Field equipment

PA/GA equipment inclusive of field switches, control stations, sounders, beacons/strobes, junction

boxes manual call points shall be specified from MEDC accredited product range (or pre-approved

equivalents) and be fully compatible with other equipment on the installation.

Ceiling Grid Support

The preferred make for switchroom and plant room ceiling support systems shall be Oglaend, Norway (or

pre-approved equivalents).

Cable Identification Systems

Cable identification systems shall be compatible with existing platform items, typically Critchley (or other

approved equivalents). Another acceptable alternative shall be Silver Fox, UK

Interposing Relay Panels

These shall be as detailed by the engineering contractor on specifications and data sheets in accordance

with project drawings. Incoming and outgoing cables shall be bottom entry unless otherwise specified on

the data sheets. The panels shall be mounted indoors and have ingress protection of IP42 minimum.

There shall be an external nameplate fitted with equipment tag number and description and a separate

label identifying voltage levels present within the panel.

Internally, incoming and outgoing cables/panel wiring shall be conspicuously identified. Cables shall be

separately routed in trunking within the panel in accordance with voltage levels. All relay connections

shall be wired down to separate incoming and outgoing terminals with different voltage levels segregated.Relays shall be of the multi-pole plug in type and be identified within the panel.






Ai r Condit ioning Equipment

Air conditioning units shall be suitably sized and rated and be of a good industrial quality from a

recognized supplier (Mitsubishi, Carrier, Toshiba, etc). The use of hazardous area A/C equipment shall

be avoided wherever possible. Where no alternatives exist, the engineering contractor shall propose a

specification that will be pre-approved by OPQL TA.

Power and control Cables

All power and control cables shall be fully compliant with OPQL General Cable Specifications, document

reference 000000-4-XPS1-SP-0001-001.

Substation and Equipment Shelter wall Cladding

The internal wall cladding for substations and air conditioned equipment shelters shall be INEXA TNF

50mm x 3m or an equivalent product from a pre-approved supplier.






APPENDIX D – Ear t h i ng an d Bond ing

General

The primary purpose of the earthing system is to reduce and control voltages on equipment to an

acceptable level under abnormal conditions and provide a conductive path to earth for fault currents, thus

facilitating rapid disconnection of faulted equipment from the electrical system. A secondary purpose is to

eliminate any risk of sparking in hazardous areas due to voltages under abnormal conditions. Such

conditions include equipment faults, static electricity build up or lightning strikes.

This document covers the primary and secondary earthing philosophy to be adopted on OPQL managed

facilities. The earthing networks on most of OPQL managed facilities are TN-S systems.

Lightning and Static Electrici ty

Lightning protection is not required nor normally provided on steel offshore platforms as a good

conductive path to earth exists by virtue of the structure, jacket and piles. There may be a requirement

for surge arrestors to be fitted to protect sensitive offshore (mainly telecommunication) equipment.

Specification of these is however outside the scope of this BoD.

For protection against lightning of onshore structures and the accumulation of static charges, guidelines

given in BS 6651 (Code of Practice for Protection of Structures against Lightning) shall be used. Earth

electrodes shall be located near the base of elevated structures that require lightning protection. This is

to ensure a low impedance lightning discharge path to earth. The electrode(s) shall be connected to the

structure to be protected and to the main earth grid using conductors of 120mm² cross-sectional area.

The combined resistance to the general mass of the earth of the electrodes providing for lightning

protection shall not exceed 10 ohm when isolated from the structure to be protected and from the main

earth grid.

Onshore metal structures like tanks, vessels etc. do not require additional protection beyond the earthing

requirements provided all structural elements are bonded to form a single conductive structure, which is

to be connected to the plant earth grid. Care should be taken to ensure that all structural elements

forming part of lighting protection system are suitable both mechanically and electrically.

Instrument Clean Earth Systems

Separate instrument clean earthing networks (to reduce/eliminate signal interference levels etc.) and

protective earthing for intrinsically safe (IS) instrumentation systems shall be provided where required.

These networks shall be segregated from the electrical primary and secondary earthing systems and

comply with appropriate codes and standards. Instrument cable earth screens, etc, are part of the clean

earth system. These are normally bonded to the clean earth system within control/equipment rooms and

insulated at the field end.

Refer to Instrument Basis of Design, document number 000000-5-XPS1-BD-0002-001 for full details of

Instrument earthing philosophy.

For avoidance of doubt, conductive instrument casings are considered part of the secondary earthing

system and shall be locally bonded to earth.






Primary and Secondary Earthing System – Offshore facilities

The platform jacket steelwork is in direct contact with sea and the seabed “earth” at all times.

Consequently the steelwork is the zero reference point regarding the dissipation of electrical fault

currents. Since the module sub-framing and all topsides main structures are welded in place, they have

reliable electrically conducting paths and interfaces. These have an adequate cross-sectional area to

safely conduct electrical currents to earth.

Platform generators, distribution transformers, switchboards, neutral earthing resistors etc. shall be

bonded with copper conductors, to ensure that high earth currents are directed to their correct return

location, preferably in an interconnected ring with copper earth bars appropriately located. These

conductors form the PRIMARY EARTHING SYSTEM.

Other items of equipment such as low voltage motors, distribution boards, UPS systems, battery and

charger units, junction boxes, cables, control panels and packaged equipment shall be bonded to the

local steelwork using copper cables. The particular methods used for these items of equipment will formpart of the SECONDARY EARTHING SYSTEM.

Earth Bonding Cable Sizes

The following cable sizes for earth bonding shall be adopted and are to be used as follows:

• HV and LV Switchboards and Main Substation primary earth loops 120mm²

• LV Equipment with a supply cable greater than 35mm² 70mm²

• LV Equipment with a supply cable between 6 and 35mm² 35mm²

• Equipment not in direct (i.e. welded) contact with platform steelwork 35mm²

• External (field) equipment with a supply cable of 6mm² or less 16mm²

• Equipotential bonding and conductive (non GRP) cable ladder racks and trays 16mm²

• Internal equipment with a supply cable of 6mm² or less 6mm²

The earth cable sizes indicated above are minimum and larger cables may be substituted as required.

Cables should be selected from Oxy General Cable Specification 000000-4-XPS1-SP-0001-001, type E1

shall be used unless otherwise specified.

Typical earthing installation details are shown on the following drawings:

• Primary Earthing System: 000000-4-XPS1-29-6821-001

• Secondary Earthing System: 000000-4-XPS1-21-6820-001

Switchboards

Each electrical switchboard shall be connected to earth at two points directly bonding the switchboard

earth bar to a Switch Room earth bar forming part of the primary earth loop.

Transformers and Generators

The earthing conductors linking the transformer or generator neutral point to the earth, via fault limiting

equipment (if fitted), shall be as short as possible and mechanically well protected.






Field Equipment

The minimum recommended size of separate bonding conductors for field equipment is 16mm² to

maintain mechanical integrity. The size of protective conductors within small power cables shall not be

less than the size of phase conductor. The armour of cables shall not be used as the sole means of

providing earth continuity.

Motors, control stations and other field equipment shall be bonded using approved standard earth bosses

welded to the steelwork.

Equipotential Bonding Test

Offshore installations provide good inherent natural equipment grounding. A measurement (using a low

resistance ohmmeter) performed between any two metal frames or between one metal frame and one

point on the structure or any two points of the structure should not give a reading above 0.5Ω.

Circuit disconnection times

Earth loop impedances shall be sufficiently low to guarantee rapid disconnection of faulted equipment

within a minimum period of time, thus minimizing equipment damage. Disconnection times should always

be within the equipment specified fault limits (normally within 1 second for main HV & LV switchgear). For

all other fixed equipment, disconnection should occur within a maximum of 5 seconds.

Smaller final sub circuits require more rapid disconnection times, taking into account requirements for

personnel protection. The following times shall be applied for final circuits not exceeding 32A:

U0 Volts Disconnection Time

Up to 120V 0.8s

120V to 277V 0.4s

277V to 400V 0.2s

Above 4000kW 0.1s

The engineering contractor shall verify circuit disconnection times by calculation and specify the

maximum earth fault impedance level required to achieve this. For further guidance concerning this

matter, please refer to the following publications:

• IEC 60364-4-41 Electrical Installation of Buildings, Protection for Safety, Protection against

electric shock.

• BS 7671 Requirements for Electrical Installations, Chapter 41, Protection against electric shock.

Earth Loop Impedance

In every new installation, an earth loop impedance measurement (using an earth loop impedance tester)

should be made to confirm the calculated values of impedance required to achieve circuit disconnection

within the specified time period before equipment is put into service. A clause to this effect shall be

included within construction workpackages.






Earthing systems – Onshore Installations

For on-shore installations electrical earthing systems, equipment and structures each installation shall

have one main earth grid connected to at least two groups of earth electrodes. These shall comply with

the requirements of IEEE 80 Guide for Safety in Substation Grounding. Potential step and touch voltage

levels shall be kept within acceptable limits.

The earth grid shall comprise copper earthing cables. Each item of equipment to be earthed shall be

connected to main earth grid by two branch earth connectors. The earth grid shall be installed throughout

the plant site in the form of a main earth ring with branch interconnections to the equipment and

structures to be earthed.

Each earthing electrode shall be sunk vertically to a depth of 2 metres below the summer water table.

The earth resistance of each electrode shall be as low as is practicable but shall in any event be such that

the electrical resistance between the main earth grid and the general mass of the earth shall not exceed 4

ohms when any one group of electrodes is disconnected. Earth electrodes shall be galvanised steel pipeor other suitable material, which guarantees low resistance and long life. Copper electrodes shall not be

used in areas with impressed-current cathodic protection. Aluminium shall not be used for any part of an

earthing system.

Use of buried un-insulated earthing cable, for achieving the desired earth resistance values, shall be

subject to approval of OPQL TA.

The connections between electrode heads and conductors shall be so executed that easy inspection and

testing of the earth resistance of individual electrodes is possible. All bare parts of underground earthing

conductors shall be suitably protected against direct contact with the surface soil so as to prevent

electrolytic corrosion of plant equipment. All earthing terminations shall be made with compression-type

cable lugs. Interconnections shall be directly clamped with compression-type branch connectors or 'Cad-

Welded'.

The metallic enclosures of electrical and nonelectrical equipment, vessels, tanks, structures, etc., shall be

bonded and earthed by connection to the common earth grid or to be provided with their own duplicate

electrodes. Pipelines shall not be used for earthing purposes.

The earth bonding cable sizes specified within this document equally applicable to onshore as well as

offshore installations unless system fault levels require larger cables to be specified and substituted.






APPENDIX E – Recom mended Il l um inat i on Level s

The lighting system shall be designed to provide the average illumination levels as given below:

Location Average Il lumination

level (lux)

Control rooms, laboratories and offices 500

Catering areas (Food preparation and Serveries) 300

Recreation areas, Dining areas 250

Switchrooms and Local Equipment Rooms 250

Indoor workshop areas 250

Plant Rooms and Indoor Stores areas 150

General plant areas with rotating equipment 150

General process areas(Static equipment and Piperacks) 100

Locker rooms and toilets 100

Outdoor stores and materials yards 50

Access ways and stairs 50

Escape lighting 5

Tank Farm areas 2 - 5

Note that emergency lighting levels available are dependent upon autonomy. Most battery backed

emergency luminaires are selectable to provide either 3hr or 1.5hr autonomy. The light output with a 3hr

autonomy is approximately half that when selected for 1.5hrs.

It is recommended that a lighting survey be conducted on completion of major installation activities. This

will consider lighting conditions under normal and emergency conditions. The lighting survey shall be

carried out with a colour and cosine corrected lightmeter. Any dark areas shall be recorded on the

lighting layout drawings and show recommended locations of additional luminaires.






APPENDIX F – Exam p le Fo rm at – Planned Main tenance Rou t in e

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APPENDIX G - Fac i l i t i es K ey Reco rds L i b rar y

Only certain categories of documentation are maintained by OPQL as key field technical information(FTI). Attached below is a reference list of the key records library documents, most of which are available

in native file format from OPQL DCC on request. Engineering contractor designs shall be based upon

key records documentation, backed by additional drawings where required.






APPENDIX H – Elec t r i cal Cons t ruc t i on and Co mmiss io n i ng Check l i s t s

All the checklists referenced below are available from OPQL DCC on request:

Electrical Basis of Design - OXY

Documents

Transcript of Electrical Basis of Design - OXY