Electrical Design

PART IIISECTION 3

1TECHNICAL SPECIFICATIONS ELECTRICAL WORKS FOR OFFSITE AUTOMATION PROJECT

CONTENTS

CHAPTER DESCRIPTION

1) Scope of Work for Electrical Engineering

2) Standard Specification for Electrical Equipment

3) Engineering Design Basis for Electrical

4) Electrical Engineering Job specification

5) Standard Specifications for 415 V Motor Control Center

6) Standard Specification for Medium Voltage Motor

7) Standard Specification for Electrical Cabling

8) Standard Specfication For Electrical Motor Operated Valve Actuators

9) Standard Specification for Uninterrupted Power Supply System

10) Standard Specification for High Voltage Motors

11) Standard Specification for Air Conditioning System

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CHAPTER 1

ELECTRICAL SCOPE OF WORK

FOR

OFFSITE AUTOMATION

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OFFSITE AUTOMATION Electrical Scope of Work

1. The scope of work of the contractor for the Offsite Automation System comprises ofDesign, Detailed Engineering, Supply, Erection/Installation, Testing andCommissioning of all Electrical equipment and systems required to meet thefunctional needs of the Offsite Automation Project.

2. The list of Electrical equipment and systems covered in the scope shall include, but notlimited to the following:-

i) All electrical drive motors

ii) Local Push Button Stations for each motor

iii) Transformer as per requirement

iv) Power cables, cable installation equipments & accessories andconduits for routing cables required

v) Motor operated Valves

vi) 415V MCC / power distribution boards / Local control panels requiredto feed electrical power loads

vii) Uninterrupted Power Supply Systems for Control Systems, Analyserand Motor Operated Valves.

viii) Earthing system consisting of provision of required earth pits at suitablelocation and connection of earth lead from all bidder suppliedequipments

ix) Lighting System inclusive of lighting fixtures, fitting and switches.

x) Air conditioning systems for control rooms and other locations whereinstrumentation systems that require air conditioning are installed.

xi) Building electrification works

xii) Motor Operated Valves

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3. All civil and mechanical works, such as foundations, structural works, false ceilingworks, ducting etc., related to the completion of the electrical scope of work isincluded in the scope of the contractor.

4. All equipment and components shall be procured from the manufacturers listed in theenclosed approved vendor list.

5. Bidder shall be provided suitable feeders in the substation nearer to the load center byCPCL subjected to the availability of spare feeder. PURCHASER reserves the right toreserve spare feeders for future maintenance purposes. In case, required number offeeders could not be spared by CPCL, the Bidder shall erect a separate distributionboard for the purpose inside the substation / extend the existing panels if loadconditions permit. In case of extension, extension panels shall be of same standards asthat of existing panels and preferably of same make.

6. Bidder shall note that his scope of work includes supply of all material and resource.CPCL will not provide any material or resource.

7. The bidder shall design, supply, erect , test and commission a centralised airconditioning and ventilation system for the following

(a) Control Room(b) Rack room(c) Shift In-Charge room(d) Computer room(e) Operator room(f) UPS Room(g) Operator Room(h) Dining Room

The sizes of the rooms shall be as per the drawings enclosed.

8. The bidder shall design, supply, erect, test and commission the Uninterrupted powersupply (110 V) system for providing power supply to DCS system and analysers shallbe considered. The UPS shall be parallel redundant with by-pass facility having threeindependent incomers. The batteries shall be Ni-Cd type and shall provide a minimumback up of 30 minutes in event of mains failure. Suitable power distribution boardshall be provided for feeding to various devices. UPS in the control room shall be forcontrol room instrumentation and other requirements only. UPS requirements ofanalyser sheds shall be met through separate UPSs in those locations.

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9. The bidder shall design, supply, erect, test and commission the DC power supply (110V) system for providing power supply to Critical lighting, etc. The battery chargershall be of dual float cum boost type and the batteries shall be Ni-Cd type or Plantelead acid and shall be designed to provide a minimum back up of 2 hours in event ofmains failure. Alternatively, the vendor can source DC from OMS/Ref-I substation bylaying suitable cables. For analyser shelters only portable emergency lights shall beprovided.

10. Additional outdoor lighting shall be provided wherever operation of equipments areenvisaged.

11. HT motor feeders will be made available in OMS/REF-I HT substation by CPCL. OneLT (415V) feeder of required capacity will be provided by CPCL in each of the SS4,SS5, Ref-I substations. Further power distribution, including that for inputs to UPS,Airconditioning plant MCC, shall be carried out by the contractor through separateswitchboards.

12. Vacant space with floor opening available in the above mentioned substations can beused by the contractor for erection of his panels. However, if the space is not sufficientthe contractor has to extend the substations/ floor openings, as required.

13. Ten number telephones of premier model of tatafone make shall be provided andinstalled in the control room. All required cabling from the junction boxes shall be laidand connected by the contractor.

14. Bidder shall involve CPCLs Engineers at each and every stage of the project andshall proceed only after obtaining the necessary approval from CPCL.

15. The scope includes supply of miscellaneous items as per specifications.

16. The scope includes supply of Special tools and test equipment, calibration andmaintenance of the system.

17. The vendor shall supply all final drawings, documents. Operating / maintenancemanuals, test reports, commissioning reports, etc in following form :- 6 nos. ofhardcopies including tracing & prints for drawing. One set in digitized form in floppyand one set in CD.

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18. Supply of two years Operational, Mandatory & Commissioning Spares as per sparephilosophy Warranty and Post-Warranty Maintenance etc. mentioned in thespecifications of equipment.

19. BIDDER IS ADVISED TO CAREFULLY SCRUTINIZE THE TENDERDOCUMENT, SPECIFICATIONS, AND INSTRUCTIONS. ETC AS CONTAINEDHEREIN AND TO UNDER TAKE A SITE VISIT BEFORE SUBMITTING THEIROFFER FOR CPCLS REVIEW AND ACCEPTANCE. ANY ADDITIONS, WHICHSHALL BE REQUIRED DURING THE EXECUTION OF THE PROJECT TOMEET THE FUNCTIONAL REQUIREMENT, SHALL BE PROVIDED BYBIDDER AT NO EXTRA COST.

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CHAPTER 2

STANDARD SPECIFICATION

FOR

ELECTRICAL EQUIPMENT

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CONTENTS1.0 SCOPE

2.0 CODES AND STANDARDS

3.0 SITE CONDITIONS

4.0 AREA CLASSIFICATION AND EQUIPMENT SELECTION

5.0 EQUIPMENT SPECIFICATIONS

7.0 EARTHING SYSTEM

7.0 LIGHTING SYSTEM

8.0 FACILITIES INSIDE CONTROL ROOM

9.0 CONTROL STATION

10.0 INSPECTION, TESTING AND COMMISSIONING

11.0 SPARES

12.0 DRAWINGS AND DOCUMENTS

13.0 OTHERS

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1.0 SCOPE

1.1 This specification along with specific job requirements. Standard specifications, etc.defines the requirements for design, engineering, supply and, where included in jobrequirements, installation, testing and commissioning of electrical equipment andfacilities for the OFFSITE AUTOMATION PROJECT.

1.2 For the purpose of this specification, the term `package equipment' or `package'denotes the all equipment to be supplied or work to be carried out by the vendor.

1.3 It is not intended to cover all aspects of design but to indicate the basic requirementsonly. Vendor shall ensure that the design and installation of the equipment is carriedout as per good engineering practice to meet the requirements of safety, reliability,ease of maintenance and operating, aesthetics, scope of further expansion andmaximum interchangeability of equipment. Vendor shall acquaint himself withCPCL standards, specification and field testing procedures as deemed necessary forproper execution of the work.

1.4 Compliance with this specification and /or review of any of the vendor documentsshall not relieve the vendor of his responsibility and his contractual obligations withregard to the completeness and satisfactory operation of the project.


2.1 All electrical equipment and the complete package shall meet the requirements ofthis specification and enclosed data sheets in addition to the relevant Publicationsand Codes and Practice of Bureau of Indian Standards, , statutory regulations andgood engineering practices. Complete system must be also conform to the latestrevisions of the following:a) Indian Electricity Act and Rules framed thereunderb) Fire Insurance Regulationsc) Petroleum Rules and any other regulations laid down by Chief Controller of

Explosivesd) The Factory Act and regulations laid down by Factory Inspectoratee) Regulations laid down by local statutory authorities and Electrical Inspectoratef) Oil Mines Regulations (For Projects under DGMS jurisdiction).g) OISD Standards h) Requirement of other statutory bodies as applicable -eg. CEA, CCE, TAC,

DGFASLI

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2.2. Vendor shall obtain all necessary approvals from statutory authorities (CentralElectricity Authority) for materials, plant design/drawings and complete installation.The statutory approval from CEA shall be obtained by the vendor prior to energisingthe electrical installations.

2.3 Where Indian Standards do not exist, the relevant IEC/British/ German (VDE)standards shall apply. Any other international standard may also be followedprovides it is equivalent to or more stringent than the standards specified above.

2.4. In case of any discrepancy/conflict between this specification and the specified codesand standards, the following order of decreasing precedence shall govern:

i) Statutory Regulationsii) Electrical Design basis and Equipment Data Sheetsiii) Job specifications

iv) CPCL Standard Specifications and Installation Standards etc.iv) Codes and Standards

In case of any discrepancy/conflict between the specification of the same level [2.4 i)to iv) ] mentioned above, the better standard among them shall be adopted.

CPCL's concurrence shall, however, be sought and obtained before taking a decisionin the matter.

3.0 SITE CONDITIONS

Provided in design basis.

4.0 AREA CLASSIFICATION AND EQUIPMENT SELECTION

4.1 In case of storage handling or processing of flammable materials within the batterylimits of the package, area classification shall be carried out in line with IS : 5572,Petroleum Rules and DGMS guidelines where applicable. Where specified, thevendor shall furnish an `Area Classification Drawing' indicating the zones ofhazardous area and the applicable gas groups. A list of flammable materials handledalongwith their properties like flash point, ignition temperature, explosive limits etc.shall also be furnished.

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4.2. Selection of the type of all equipment for use in hazardous areas shall be done inaccordance with IS : 5571 and DGMS regulations where applicable. The electricalequipment shall meet the requirements of relevant IS, IEC or NEC standards.Increased safety type Ex (e) equipment shall not be permitted for use in Zone -1areas. For Zone-2 areas, Increased safety type Ex(e) or Non sparking Type Ex(n)equipment shall be provided as a minimum, subject to the same being acceptable tostatutory authorities. Ordinary safe type electrical equipment shall not be used inZone -2 areas (even though this may be permitted by NEC for Div.2 areas).

4.3. Electrical equipment for hazardous areas shall be certified by CMRI and approvedby CCE/DGMS as applicable (or equivalent recognised testing agency and statutoryapproval authority) for installation and use in the specified hazardous area.Flameproof equipment of indigenous origin shall be `BIS' market. Vendor shallfurnish the necessary certificate indicating such approvals.

4.4. Unless otherwise specified, electrical equipment for hazardous areas shall generallybe suitable for gas IIA and IIB and Temperature Class - T3 applicable to the selectedtype of explosion protection. In case hydrogen is handled, the gas group to beconsidered shall be IIC.

4.5. Unless otherwise agreed, electric motors for agitators/mixers, metering pumps andoil sump pumps handling flammable materials shall be flameproof Ex(d) type,irrespective of the area being classified as Zone-2 or Zone-1.

4.6. In case the Package or part of the package /equipment is to be located in a classifiedhazardous area, the same shall be indicated in the data sheet. In such a case, theoffered equipment/ package shall conform to whichever are the more stringentrequirement i.e. either due to materials being handled in the package or hazardouslocation in which package is installed.

5.0 EQUIPMENT SPECIFICATION

5.1. Specifications of each system and equipment shall be furnished by the vendor forreview by CPCL. However, certain minimum requirements for the major equipmentare highlighted in this section.

5.2. All equipment and components shall be new and supplied by CPCL approvedmanufactures. Equipment requiring specialized maintenance or operation shall beavoided as far as possible and prototype equipment shall not be accepted. All

PART IIISECTION 3


equipment shall be complete with all necessary weather and anticorrosion protectionincluding tropicalization to prevent damage due to climate, sline atmosphere, dustand corrosive vapours.

5.3. All equipment /material shall be protected for inland / marine transport,. carriage atsite and outdoor storage during transit and at site. Vendor shall be responsible forany damage to the equipment during transit. All packages shall be clearly, legiblyand durably marked with uniform block letters giving the relevantequipment/mutable details . Each package shall contain a packing list in awaterproof envelope.

5.4. All electrical components and equipment shall be sized to suit the maximum loadunder the most severe operating conditions. Rated voltage and frequency for theequipment shall be as indicated in enclosed date sheet.

5.5. All spares required for testing and commissioning the package shall be includedalongwith any special tools and tackles required for operation and maintenance.

6.0 STANDARD SPECIFICATIONSStandard Specifications have been enclosed for Induction motors, Cables, UPS,MCC, Transformer and MOV. All of the above equipment supplied by the vendorshall meet the requirements specified therein.

7.0 EARTHING SYSTEM

7.1 Earthing system design and installation shall generally be as per IS:3043. One ormore number of G.I. earth plates shall be provided for the equipment in packagedepending upon in size. All metallic non-current carrying parts of electricalapparatus, control stations, current and potential transformer secondaries, structuralsteel, vessels etc. shall be connected by at least two distinct separate earthconductors to an earth plate. All earth plates shall be bonded together and shall havethe provision for interconnection to owner's main earth grid at two points. Earthplates shall be of 3060x80x10mm size and shall be provided with adequate numberof tapped holes. Earth continuity bonding shall be provided across all pipe flangejoints.

7.2 The resistance value of earthing system to the general mass of the earth shallensure the operation of the protective device and in any case should not exceed 5ohms. Normally earthing system shall comprise of main earth grid along with

PART IIISECTION 3


suitably located disconnecting plates to provide multiple earth connectionsbetween earth grid and equipment and for connections between main earth gridand electrodes. Connections between earth electrodes and the disconnecting platesshall be done by GI strip. Connection between disconnecting plate and variousequipment shall be done by GI strip, GI wire or GI rope. Earth electrodes andconductors shall be designed to cope with the conditions imposed. The earthconductor shall be adequately sized to carry the applicable maximum earth faultcurrent without undue temperature rise. All joints shall be protected to preventcorrosion.

7.3 Design calculations and for earthing layout has to be submitted for approval.

7.4 All hardware used for earthing installation shall be hot dip galvanized for zincpassivated. Thickness of hot dip galvanizing shall be minimum 700gm/m2.Specifically provided bolts, lugs and spring washers shall be used for all earthingconnections of equipment.Following sizes of earth conductors shall be used for motors:

Upto 3.7 KW85WG GI wire5.5 to 30 KW3/8" GI fine wire rope or 35mm2 AI insulated conductor37 to 75 KW 5/8" GI fine wire rope or 70mm2 AI insulated conductorAbove 75 KW 40 x 5mm2 GI strip.

Earthing connections to equipment shall be made by means of bolts and lugsprovided specifically for this purpose.

8.0 LIGHTING SYSTEM

8.1 General lighting for areas in which equipment supplied in the package is to beinstalled shall be provided by vendor. Normal lighting system shall be fed by 415/240VAC supply.

8.2 HPMV lamps or MLL lamps shall be used for outdoor plant lighting, however toovercome the re strike time lag in case of voltage dip/ blackout incandescent lampsmay be judiciously distributed throughout the plant area. All chemical handlingfacilities shall be provided with chemical resistant fixtures. Control gear boxes shall belocated at accessible level, which should not exceed 2m above operating level.

8.3 Fluorescent lamps with electronic ballasts shall be provided for indoor lighting fornon process buildings and control rooms.

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8.4 All outdoor lighting shall be automatically controlled by synchronous timers withmanual overriding control. Lighting panels shall be used for distribution and thesepanels shall be provided with MCB + ELCB as incomer and MCBs for outgoingfeeders control and protection. Only 8 -10 fixtures shall be wired in each circuit.MCBs shall not be loaded beyond 80% rated capacity. A minimum of 25% of MCBs shall be left as spares. The lighting distribution shall not combined with powerdistribution and separate panels have to be used for power distibution.

8.5 The minimum illumination levels for the following areas shall be: Process areas - 60 LUX MCC room - 200LUX Control room - 500LUX

8.6 Design calculations and for lighting system lighting layout has to be submitted forapproval.

8.7 Lighting fixtures mounted on plat forms, walkways, stairs, High bays etc shall beinstalled in such a way that relamping can be done without the use of ladders.

8.8 Any other lighting requirements such as Local panel lighting shall be provided byvendor. Power for such local lighting shall be obtained from a suitable feeder inPDB/Local Panel.

8.9 All lighting circuits shall have provision for isolation in both phases and neutral forpackages to be installed in hazardous areas. For packages under DGMS jurisdiction,power supply voltage shall be limited to 240V between phases by the use a suitabletransformer.

9. Facilities Inside Control Room Building

9.1 Concealed conduit wiring shall be used below the false ceiling and surface conduitwiring above the false ceiling.

9.2 Adequate number of combined 5/15 Amps power sockets shall be provided.

10. CONTROL STATION:

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10.1 Each motor shall be provided with a control station in the field. The control stationshall have suitable protection for site conditions (such as flameproof, weatherproof ,dust proof, corrosion resistant etc.). and minimum acceptable IP class is 55. Canopyshall be provided to protect outdoor control station against direct rain. The controlstation shall include start & stayput type stop pushbuttons and Ammeters (for motorsrated > 18.5 KW)

11.0 INSPECTION, TESTING AND COMMISSIONING

All equipment shall be tested and inspected at vendor's works before dispatch toensure compliance with the relevant specifications and agreed qualityassurance/testing plan. Precommissioning and Commissioning tests have to becarried out by the vendor on all the electrical equipment.

The owner or his authorized representative may visit the works during manufactureor various electrical equipment/materials to assets the progress of work as well as toascertain that only quality raw materials are used for the same. He shall be given fullassistance to carry out the inspection. Owner's representative shall be givenminimum two weeks' advance notice for witnessing the final testing. The minimumtesting/inspection requirements for all components/equipment shall conform to therequirements stipulated in applicable codes and standards. Test certificates includingtest records and performance curves etc. shall be furnished by the vendor.

Vendor shall submit the field testing procedures for CPCL's approval. Field tests asper the approved procedures shall be performed on the electrical system/ equipmentbefore its being put into service. All test equipment required for this purpose shall bearranged by the vendor, in case testing and commissioning at site is included in hisscope, and test reports shall be approved by the size-in-charge before acceptance ofthe complete package.

12.0 SPARESVendor shall separately quote for 2 years' operation and maintenance spares for allelectrical equipment in the package, including but not limited to the following.Vendor shall indicate unit rates and recommended quantity for each item in his offer.All spares required for commissioning the equipment is included in the scope of thecontractor.

M.V.Motors- Terminal block

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- Terminal cover with screws etc.- Fans for critical motors.- DE, NDE end Shield

Power Distribution Board/Local Panel- Switches and fuses of all ratings- Set of main contacts and coils of all contactors- Bimetal relays- Indicating lamps assemblies/lamps- Push buttons and auxiliary devices.

13.0 DRAWINGS AND DOCUMENTS

All drawings, SLD s design calculations and data sheets has to be approved by CPCLbefore issuing for construction. Four copies of As-built documents/vendor drawings shallbe provided by the vendor as per contract. Additionally, one set of all as-built documents/vendor drawings in bound volumes and/or in the form of electronic files on specifiedmedia shall be submitted to CPCL alongwith certified and updated drawing schedule. Thefollowing shall also be included.

a. Design and installation instruction manual including design documents,certificates relating to type/acceptance/special tests, description of proceduresand description of field testing procedures after installation.

b. Operating instruction including description of start-up procedure and descriptionof conditions of use.

c. Maintenance instructions including precautionary maintenanceinstructions/periodic inspection programmes, setting instructions, procedures forremoving and replacing all parts and accessories included in the spare parts list,and list of spare parts and consumables together with all information requiredfor ordering them from manufacturers.

Sub-suppliers of individual components shall be clearly identified. Communicationaddress shall be indicated for each reference.

14. OTHERS :

14.1 Lifting facility for motors have to be provided where ever necessary.

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14.2 All equipments supplied (except fuses and bulbs) shall have warranty for 12 monthsfrom the date of commissioning.

14.3 Any deviation from the specifications is not acceptable, unless it is specificallyapproved by CPCL. Deviations to Electrical specifications, if any envisaged by thevendor shall be submitted clause wise, as a separate Annexure to the technical bid, forconsideration of CPCL.

14.4 Any discrepancies between different specifications provided in this document shall benotified clause wise in a separate Annexure to the technical bid and the specification tobe adopted shall be indicated there in. However CPCL decision on the standard to beadopted shall be final.

14.5 If some of the Specification specified anywhere in the document is not part of thedocument the same shall be provided by CPCL on request.

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CHAPTER 3

ENGINEERING DESIGN BASIS

FOR

ELECTRICAL

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1. SITECONDITIONS

A. Equipment design temperature (IS 9676) : 40.0 DEG C

B. Soil Resistively : * ohm m

C. Min. temps. for battery sizing : 10 DEGC

D. Min. Temp. For Electric heat tracing : 10 DEGC

E. Seismic zone(IS 1893) : *

F. Altitude above mean sea level : 3.5 m

G. Design wind velocity : 150 km/hr. or as perIS 875, Which ever ishigher.

2.0 POWER SOURCE DETAILS

2.1 General

Independent system or extension of existing system : Extension of existing system.

2.2.Grid Supply:

A. Name of grid sub station : To be decided later.

B. Number of feeders : Later

C. Length of feeder / conductor size : Later

D. Voltage : 6.6.KV or 415 V + 10%

E. Frequency : 50 Hz + - 3%

F. Min / max fault level / BIL : 40 kA / 60 kV

G. Design fault level / BIL : 40 kA / 60 kV

H. System neutral earthling : Resistance Earthed

I. Minimum load p.f. stipulated by Supply authority : 0.9

J. Parallel operation of incomers : No

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3.0. POWER SUPPLY DISTRIBUTION SYSTEM

3.1. Voltage and frequency variation (Refer cl.6.6.for design voltage / frequency variation for motors)

A. AC System

Voltage : 6.6.kv + - 10% (motors rated above 160KW) 415 V + - 10% (motors rated less 161KW)

Frequency : 50Hz + - 10%

B. DC System (at system output terminals)Electrical Control, Lighting etc. : 110V + - 10%

3.2 Utilisation voltage & operating philosophy

A. Primary HV distribution voltage : 6.6kvB. Secondary HV distribution voltage : 6.6kvC. Primary HV distribution system neutral : Resistance earthed

D. Secondary HV distribution system neutral : Resistance earthed E. HV motor voltage : 6.6kv (above 160 kW) F. Auto transfer at 6.6KV Bus : Not Applicable G. Auto transfer at MV (At PCC Level) : Yes H. Continuous Parallel operation of Incomers

- HV : No- MV : No

I. Load shedding : Provision for wiring of trip contact in HV SW. Gr. J. MV motor voltage (415 VAC) : : 0.37 kW to 160 kW K. Power factor improvement capacitors : NA L. Battery charges : 415 V AC M. UPS System : 415 V AC N. AC Lighting / Power Panels and Auxiliary Boards : 415 VAC O. Welding Receptacles : 415 V AC P. Bulk loads like Process Heaters etc. : 415 VAC Q. Normal Lighting / Emergency Lighting : 240V AC R. Motors rated below 0.37 kW : 240 V AC S. Convenience outlets : 240 V AC T. DC Motor : DC motors not envisaged in hazardousareas. ( e.g. emergency lube oil pump motor etc.) U. MOVs : 415V AC

3.3 Utilisation voltage for critical suppliesA. Normal Instrumentation power supply : # V ACB. Critical instrumentation power supply : # V AC/ DCC. Shut down system power supply : V, AC (UPS) /DCD. Switchegear protection and critical lighting power supply : 110 V, DC

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E. DC supply for instrumentation # Refer Instrument design basis : Independent systemF. Fire alarm system power supply : 240 V. AC Normal

4.0 Metering for grid incomers ( If applicable)

A. I) protection relays for 11 or 33kv switch gear : NAII) Protection relays for 6.6kv switch gear : On switch gear

B. 11kv or 33KV Switch gear control : NA i) ON/ OFF for testing purpose : NA ii) Normal operation : NA

C. 6.6KV Switch gear control i) ON / OFF for testing purpose : From switch gear ii) Normal operation for Incomers/ Bus Tie/ Transformers feeders : From switch gear iii) 6.6KV motors feeders : Field / DCS control room

D. Annunciation paneli) For each substation in operation room : NAii) For Power Plant control room : NAiii) UPS and DC trouble : shall be provided in control room DCS

E. Numerical Protection / Monitoring system (MMI/ SMS for each substation) i) EHV system : NA ii) HV Switch board : Yes iii) 415V MCC : No iv) 415 V MCC : No

F. MMI / SMS system separate for EHV / HV system relays : NA

G. Centralised Lighting control From operator room. : NA

H.. Microprocessor based system for control : interface I/ O requirement etc. shall beInterlocking and monitoring of electric MR. furnished by CPCL for inclusion inswitchPower system. Gear.

I. Limiting Conditions for Motor start up (e.g. starting current limitation or method of starting ) i) HV Motors : Motors starting current as per standard specification for motor rated upto 2500KW and Motor starting current limited to 400% of normal Current for KW more than 2500kw.

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ii) MV Motors : As per standard specification unless other wise specifically mentioned.

iii) Method of starting : Direct on line (DOL) For large HV motors

iv) Method of starting for large MV Motors

(Above details shall be forwarded by CPCL to CPP Contractor to decide machineparameters and system design)

G. Isolation for remote transformers : Push button near transformer bay for tripping remote Breaker.

4.3 Protection devices for power distribution system shall be as indicated below.Requirements for switchyard, power generation and D.G (If required) shall be as per cl.14.0 of this document or as shown on the single line diagram and data sheets

Transformer feeder Motorfeeder

Out goingFeeder

Incomer

Relay number (L.Vwinding> 3.3kv )

(L.Vwinding< 3.3kv)

HV&MV above55 kW)

HV MV/PCC/PMCC

HV MV /PCC/

PMCC51 IDMTL over currentrelay

Yes Yes - Yes Yes (4) Yes(12)

Yes (4)

51 N IDMTL earth faultrelay

Yes (7) No - Yes No Yes(12)

Yes (4)

51G back up earth faultrelay (secondary neutral)

Yes Yes - No No No No

Motor protection relay withlocked rotor feature (50,50N, 46,49, 50L /R)

No No Yes No Yes (8) No No

64 R instantaneousrestricted earth fault relay(secondary side)

Yes No - No No No No

50 instantaneous over current relay.


50N instantaneous earth-fault relay.

Yes (6) Yes - No No No No

87 differential protectionrelay

Yes (1) No Yes (2) Yes(3)

No Yes No

86 tripping relay Yes Yes Yes Yes Yes Yes Yes95 trip circuit supervisionrelay.

Yes Yes Yes Yes No Yes No

63 auxiliaryrelay(transformer)


27,2 under- voltage relay - - No(13) - - Yes Yes (5)

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Transformer feeder Motorfeeder

Out goingFeeder

Incomer

Relay number (L.Vwinding> 3.3kv )

(L.Vwinding< 3.3kv)

HV&MV above55 kW)

HV MV/PCC/PMCC

HV MV /PCC/

PMCCwith timer. (5)25 check synchronisationrelay.

- - - - - Yes(9)

Yes (9)

NOTES :

1. FOR transformers rated 5 MVA and above.

2. For motors rated 1500 kW and above.

3. For critical / long feeders and plant feeders connected to main power generation

&distribution bus.

4. _______.

5. Where ever auto transfer feature is provided.

6. Instantaneous earth fault 50 N shall be provided only for transformer with delta

primary.

7. Directional IDMTL earth fault 67N shall be provided only for transformer with

star primary.

8. For motor feeders rated 75 kW & above.

9. For switch gears having bus transformer scheme, where continuous or momentary

Paralleling in envisaged, check synchronising relay shall be integrated with overall

paralleling scheme.

10. The bus tie feeders in HV switch boards shall be provided with 51, 51N, 86 and

95 relays.

11. HV capacitor bank feeders shall be provided with 51, 51N, 59 (over voltage),

60(Neutral displacement), 86 and 95 relays.

12. In case of HV switch board with parallel operation if incomers, following

additional relays shall be provided.

i) One set of 87B (Bus differential) and 95 B( Bus wire supervision) for each

bus section.

ii) 67 and 67N (Directional IDMTL over current & earth fault) relays for the

incomers.

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13. The following feeders shall be provided with timers for delayed tripping on bus under

voltage while the under voltage relay shall be common for the bus:

i) HV & MV capacitor feeders

ii) HV and MV breaker controlled motor feeders or contractor feeders with

DC- control supply.

14. One no. DC supply supervision relay (80) shall be provided for each incoming DC

supply to the switchboard.

15. One set of bus differential relays (87B) and bus wire supervision relay (95B) for each

bus section shall be provided for HV switch boards connected directly to generation

buses and those used as extension buses at remote substation.

4.4.The metering devices in HV and MV switchboard shall be as below.

Feeder type A V Hz PF MW MWH HourRun

MVAR

MVAH MVA

HV Incomer X X X X - X - - - -HV Bus Tie X - - - - - - - - -HV Transformer X - - - X - - - -HV Bus P.T - X - - - - - - - -HV Plant Feeder X - - - - X - - - -HV Motor X - - - - X

(kWh)X - - -

HV Capaciter X X - - - - - - - -PCC/ PMCCIncomer

X X - X - X(kWh)

- - - -

PCC/ PMCC BusTie.

X - - - - - - - -- -

PCC Bus Tie - X - - - - - - - -ACB Out going X - - - - X(kW

h)- - - -

MV Motor(>- 75kW)

X - - - - - - - - -

MCC/ ASBIncomer

X X - - - - - - - -

MCCB/SFU Outgoing (>- 250A)

X - - - - X(kWh)

- - - -

LDB Incomer X X - - - - - - - -DG Set X X X X X(kW

h)X(kWh)

X - - -

5. Substation Design

PART IIISECTION 3


5.1. EHV Switchyard (IF applicable) NA A. Type : String bus / Tubular bus B. Structure : Galvanised C. Bus material : Aluminium / Copper

5.2. HV / MV Substation

HV MVElevated with trays in cable cellar Yes YesRaised with internal trenches No Yes(for MCC room)All top cable entry with trays belowceiling

No No

Pressurisation against ingress of dust Yes YesAir conditioned room for operator /Variable speed drives / Annunciatorpanel / MMI system/ Exiter panel etc

Yes Yes

Final paint shade for switchboard /Busduct / Pressurisation duct / all elect,equipment, Panels, JB etc.

Shade 631as per IS -5

Shade 631as per IS 5

5.3. Specific Equipment Locations

A. Batteries : Separate room in sub station / control room for electrical and instrumentation system respectively.

B. Battery charger : Air conditioned room

C. Variable speed drive panels/ Thyristor : Air- conditioned room Controlled panels.

D. UPS System : Air- conditioned room in control room

E. Lead- Acid and Nickel- CadmiumBatteries in separate rooms. : Yes

F. Annunciation panel : Operator room in substation.

6. EQUIPMENT DESIGN

6.1. EHV Switchyard (if applicable)* : NA

A. Bus bar system : Single

B. Circuit breaker type : SF6

C. Isolator type : Center break

6.2. HV Switch board

PART IIISECTION 3


A. Execution : DrawoutB. Bus bar : SingleC. Circuit breaker type : VacuumD. Motor Control : BreakerE. Separate : No

6.3. Current Transformer (CT)/ potential Transformer (PT)

A. CT Secondary- Protection : 1A- Metering : 1A

B. PT Secondary : 110 V AC

6.4.Transformers (Power / distribution)

Transformer Vector group Tap changer Soak pit Preferred rating(MVA)

Main power transformer NAGenerator unittransformer

NA

Intermediate powertransformer

NA

Dedicated (eg for VSD) As Reqd Off circuit LaterDistribution transformer(< - 2000 KVA)

Dyn 11 Off- circuit No 2MVA Later

6.5.MV SwitchboardA. Execution

i).PCC / PMCC Breaker panels : Drawout / Single front contractor feeders : Drawout, Single / Double frontii). MCC : Drawout : Single / Double frontiii). ASB : Fixed : Singleiv). LDB : Fixed : Singlev) .Motors PMCC : Above 55KW Upto 160 kW MCC : Upto 55 kW

B. Motor Starter Typei). Contactor and switch fuse with over load relay : Upto 22 kWii). Contactor, switch fuse & CBCT for : Sw. fuse 250 A & for motor

feeders above 22 KW up to 55 KWwith earth fault protection

iii) Contactor and switch fuse with motor protection relay : More than 55 KW and up to 75 KW. iv) Air circuit breaker with motor protection relay : Above 75 KW upto 160 KW v). Contactor and MCCB with over load relay : Not applicable vi) Contactor, MCCB & over load relay with CBCT for earth fault protection : Not applicable

C. Motor Controls

PART IIISECTION 3


i). Auto/ Manual switch : : DCS in control room @

ii). Local/ remove switch : DCS in control Room @

iii). Normal / Standby switch : DCS in Control Room @

iv). Sequence interlock : PLC in control room @

v). Process interlock : PLC in control room @

vi) Reacceleration equipment : Switch gear in substation

@ To be provided as per process package / operating philosophy.

vii) Control voltage for contractor Starter : 220 V AC

viii) Control supply for contractor starter : Control transformer.

6.6.MotorsMotors High voltage 415 volts

Enclosure : Indoor Outdoor

IP55IP55

IP55IP55

Insulation class F (Temp. Rise limited to B) F (Temp. Rise limited to B)Terminal boxAnti- condensation heater Yes Above 30kWAdditional canopy (out doormotors)

Yes Yes

Design voltage / frequencyvariation

+ - 10% / + - 3% + - 10%/ + - 3%

6.7. UPS System A. Redundancy : 100% B. Type of redundancy : Parallel redundant for UPS for DCS

power Non redundant for Analyser shelter

UPSsC. Back up time : 30 minutesD. Inverter by pass transformer : StaticE. By pass transfer control : Auto / ManualF. Battery type : Ni- Cd for capacities above 5 KVA

SMF for lesser capacitiesG. Battery execution : Single up to 600 Ah. Parallel

bank above 600 Ah.

6.8.Communication System

A. Plant Communication System : NAB. Telephone System :Yes

C. Telephone System & plant communication system: Separate

D. No. of intercom & P&T lines : Later

E. Battery type :

PART IIISECTION 3


F. Battery back up time : 2 Hrs.

6.9. Fire Detection &Alarm System

A. Type : Analogue addressable

B. Name of buildings to be Provided with detectors : Substation / Control room

building etc.

C. Battery type : VRLA

D. Battery back up time : 48 hrs. (Normal) + 30 minutes. (Alarm)

E. Detection System : Break Glass/ Smoke and Temp. Detector.

F. Siren for the plant : Not Attended

6.10. DC System

If DC Supply is required the same shall be sourced from a separate dual float cum

boost charger and DCDB.

A. Battery type

i) Switch gear Protection ,Control & critical lighting. : Ni -cd

ii) Instrumentation System : Ni cd

iii) Diesel Engine Starting : NA

iv) DC Motors :

B. Battery back up time

i) Switch gear Protection & Control : 2 Hours

ii) Critical lighting : 2 Hours

iii) Instrumentation : 30minutes

iv) Diesel Engine Starting : NA

v) DC Motors : NA

6.11. Cables

The power and control cables shall have the following minimum cross sectional areas:

a). Medium voltage power cable : 25 mm2 (Aluminum) / 2.5. mm2 (Copper)

b). Controls cables : 2.5 mm2 (Copper)

c). Lighting : 2.5 mm2 (Copper)

d) Communication system : 0.9 mm dia (Copper) jelly filled

e). Fire Alarm system : 1.5. mm2 2.5. mm2 (Copper) twisted pair $

PART IIISECTION 3


Note : 1) For lighting inside the building, minimum 1.5 mm2 copper conductor, PVCinsulated wire shall be used in conduit system (for circuit and point wiring),with proper colour coding.

2) All power cables up to 16mm2 shall be of copper conductor. 3) Cable size are indicative only and same shall be finalized as per equipment / Manufacturers recommendation.

7. Cabling System7.1. Cable details

Design Criteria High Voltage 415 voltsLoads located beyond 1 km Cable -Loads located 200 1000 m 3 -core cable 3 - core cableLoad located upto 200m Cable Cable / Bus trunkingLoads beyond 1 kA ratting Bus duct/ Cable Bus ductRecommended limiting size ofmulti core cable (mm2)

300 300

Short circuit with stand time(seconds)

0.2 (Out going ) / 0.06 (Plant)/1.0 (Incomer)

N.A

Insulation voltage grade Unearthed for 6.6KV EarthedType of cable insulation XLPE PVC

7.2. Cable laying philosophy

A. Process area : Above ground in overhead cable tray/ directly buried

B. Off site paved area : Above Ground cable tray (on sleeper / Overhead rack) or

RCC trench/ directly buried

C. Offsite unpaved area : Above Ground cable tray (on sleeper / Overhead rack) or

RCC trench or directly buried type.

D. Cables for non hazardous area : Armoured.

E. Type of cable trays : Galvanized prefabricated

F. Special requirements : Cables for fire water system shall be taken on exclusive

route through underground trench starting from main substation

G. Road Crossings for under ground cables : Cable culvert.

H. Road Crossings for above ground cables : Over head cable bridge / Cable culvert

8.0. Earthing System

A. Earth electrode : GI Pipe

B. Main earth loop : GI strip

C. Substation earth loop : GI strip

D. EHV switch yard earth grid : GI strip / MS with corosion compensation NA

PART IIISECTION 3


E. Lightning conductor : As per IS: 2309.

9.0. Lighting System

9.1. Supply System

A. Centralised with separate transformer : No

B. At each substation with separate transformer : Yes

C. Separate metering required : Yes

9.2. Control Philosophy

A. Out door yard : Auto / Manual ; Centralised / Local

B. Street lighting : Auto / Manual ; Centralised / Local

C. Out door process area : Auto / Manual ; Centralised / Local

D. Process building : Auto / Manual ; Centralised/ Local

E. Auto control : Synchronous timer.

F. Lamp type for Outdoor lighting : HPSV / MLL/ Metal Halide lamp /HPMV

G. Panel execution : LDB connected to MCB panels.H. ELCB at incomer of : Yes lighting & Power Panels

9.3. AC Emergency Lighting:

A. Name of process plants : NA

B. Name of buildings : Control room to be provided

C. Power supply : NA

9.4. DC Critical Lighting For Escape

A. Name of process unit : As per OISD guidelines

B. Name of building : Substation, control room Buildings, ACplant etc.

C. Power supply : 110 V DC

9.5.Wiring Type:

A. Process plant / Building / Shed : Armoured cable

B. Large service building : Concealed conduit

C. Buildings with false ceilling : Cables / surface conduit above false ceiling.

D. Substation (Switch gear Room) : METSEC channel

E. Substation(Cable Cellar) : Armoured cable

F. Other buildings : Surface armoured cable / Surface conduit

PART IIISECTION 3


9.6 Specific Lighting Requirements

A. Aviation lighting : NA

B. Navigation lighting : No

C. Security lighting for peripheral road

Boundary wall : NA

D. Type of control gear for HPMV/ HPSV lamps for

Process units, Plant / non plant building : Separate

E. Control gear box location : Accessible level(Not more than 2 meters above

operating level) for separate control gear.

F. Type of flood light mast : Telescopic tubular (30m High lighting mast) with

integral power control.

10. Electric Heat Tracing System

A. System Design Basis : Product Classification approach.

11. Electrical Equipment for Hazardous Areas

11.1 The electrical equipment for hazardous areas shall be selected as per IS 5571 and

petroleum rules. The minimum requirement is summarised below.

Zone-I Zone-IIEquipment

Gas Group IIA,IIB Gas Group IIC Gas Group IIA,IIB Gas Group IIC

MV Motors Ex d Ex-d Ex-e Ex-e

HV Motors Ex-d / Ex p Ex d/ Ex-p Ex-e Ex-e

Push Button Station Ex-d Ex-d Ex-d Ex-d

Motors Starters Ex-d Ex-d Ex-d Ex-d

Plug & Socket Ex-d Ex-d Ex-d Ex-d

Welding Receptacle Ex-d Ex-d Ex-d Ex-d

Lighting Fixturesi) Lighting

fittingii) Control Gear

Box

Ex-dEx-d

Ex-dEx-d

Div.2 Ltg.(IS 8224)Ex-d / Ex-e

Div.2 Ltg.(IS 8224)Ex-d/ Ex-e

Junction Boxes Ex-d Ex-d Ex-e Ex-e

PART IIISECTION 3


Hand Lampsi)Light fittingii)Transformeriii)Plug & Socket

Ex-dEx-dEx-d

Ex-dEx-dEx-d

Ex-dEx-dEx-d

Ex-dEx-dEx-d

Break Glass Unit

(FireAlarm System)

Ex-d Ex-d Ex-d Ex-d

Lighting Panel /

Power Panel

Ex-d Ex-d Ex-d Ex-d

Transformers Hermetically sealed with surface temperature not exceeding 200 0C

Notes :

1. The electrical equipment for hazardous areas shall generally be suitable for gas

group IIB and temp classification T3 as applicable to the selected type of

explosion protection. In case of hydrogen of hydrogen or hydrocarbon mixtures

having more than 30% volume hydrogen, the gas group to be considered shall

be IIC.

11.2.As additional safety features, the following requirements for electrical equipment shall

be followed.

A. All electric motors for agitators / mixers and metering pumps handling flammable

material shall be flame proof type irrespective of the area being classified as zone -2

or zone -1.

B. All electric motors for vertical oil sump pump shall be flame proof type.

C. Irrespective of the area classification (whether zone -1 or zone 2 ) all lighting fittings

with in the storage areas shall be flameproof type.

D. Irrespective of the area classification (whether zone 1 or zone-2 ) , all motors and

lighting fittings within the pump house (station) associated within the loading /

unloading gantries shall be of flame proof type.

E. All emergency / critical lighting fixtures and associated junction boxes in hazardous

areas (whether zone -1 & zone 2 ) shall be flameproof type.

F. Even though fired heaters in process units are not considered ammonia as refrigerant,

the room housing air conditioning equipments associated with fired heaters in process

units shall as a minimum be suitable for installation in Zone -2 area.

PART IIISECTION 3


G. Where air conditioning system is designed considering ammonia as refrigerant, the

room housing air conditioning equipment shall be adequately ventilated to classify it is

a safe area. For additional safety the following shall be considered:

! 100% standby system for ventilation

! Location of MCC / local panels in adjacent separate room.

! Instrumentation to be flameproof type or hermatically sealed.

! AC plant room motors suitable for zone 2 area.

! Lighting in AC plant room suitable for zone -2 area.

H. All electrical equipment installed in Analyser room shall be flameproof type suitable forgas group IIA, IIB , IIC irrespective of the area being classified as Zone 1 or Zone -2.

12. Statutory Approval

Statutory Authority for Electrical Installation : Central Electrical Inspectorate

Statutory approval / License For hazardous area equipment : For indigenous equipment CMRI Test certificates, CCE, DGF

ASLI approval certificates and BIS License (for flameproof equipment)

13. Cable Sizes for MV Motors13.1 Direct on line (D.O.L) start motors

Cable DetailsMotor Rating Number

of runsNo. of cores

per runConductormaterial

Conductorsize mm2

Below 3.7 kW 1 4 Cu 43.7kW 1 4 Cu 65.5kW 1 4 Cu 107.5kW 1 4 cu 169.3 kW 1 3 Al 25

11K 1 3 Al 3515W 1 3 Al 5022kW 1 3 Al 7030kW 1 3 Al 7037kW 1 3 Al 9545kW 1 3 Al 12055kW 1 3 Al 15075kW 1 3 Al 18590kW 2 3 Al 120110Kw 2 3 Al 120

125/ 132 kW 2 3 Al 185160kW 2 3 Al 185

PART IIISECTION 3


180kW 3 3 Al 18513.2 Cable sizes for motors not conforming to above table (e.g Extended distances, Reduced

voltage starting) shall be as below.13.3 Cable sizes mentioned above are applicable for a distance of maximum 350 m and for

2/4/6 pole motors. Cables sizes for other distances and low speed motors shall beworked out by the engineering contractor.

CHAPTER 4

JOB SPECIFICATION

FOR

ELECTRICAL FACILITES

PART IIISECTION 3


CONTENTS

1.0 SCOPE

2.0 CODES AND STANDARD

3.0 STATUORY REQUIREMENTS

4.0 SYSTEM DESIGN PHILOSOPHY

5.0 EQUIPMENT DESIGN PHILOSOPHY

6.0 SUBSTATION DESIGN PHILOSOPHY

7.0 INSTALLATION DESIGN PHILOSOPHY

PART IIISECTION 3


1.0 SCOPE

This specification along with the applicable project design data shall form the basis for

developing detailed design and engineering for electrical facilities including electrical

power system, electrical equipment, plant communication system, fire alarm system and

electrical installation etc.


The main codes and standards, considered as minimum requirements, are as follows.

Latest version of these shall be followed:-

IS 9676 : Reference ambient temperature for electrical equipment

SP- 30 : National Electrical Code(NEC) BIS Publication

IS- 13234 : Guide for short circuit calculation in three phase AC system.

IS- 5572 : Classification of hazardous areas having flammable gases & vapours

for Electrical installations.

IS- 5571 : Guide for selection of electrical equipment for hazardous area.

IS- 4201 : Application guide for C.T.

IS- 4146 : Application guide for V.T.

IS- 6665 : Code of practice for Industrial Lighting.

IS- 3646 : Code of practice for Interior Illumination.

IS- 1944 : Code of practice for lighting of public thoroughfares.

IS- 13346 : General Requirements for electrical apparatus for explosive gas

atmospheres.

IS 13408 : Code of practice for the selection, installation & maintenance of

electrical Apparatus for use in potentially explosive atmospheres.

IS- 3043 : Code of practice for Earthing.

IS- 3716 : Application guide for Insulation Coordination.

IS- 10561 : Application guide for Power Transformer.

IS- 10028 : Code of practice for selection, installation & maintenance for switchgear & control gear

IS- 8478 : Application guide for on load tap changers.

IS- 10118 : Code of practice for selection, installation & maintenance for switch

PART IIISECTION 3


gear & control gear.

IS- 7689 : Guide for Control of undesirable static electricity.

IS- 2309 : Code of practice for the protection of buildings and allied structures

against lighting.

IS 12360 : Voltage bands for electrical installations including preferred voltages

and frequencies.

IS- 3961 : Recommended current ratings for cables.

IS- 7752 : Guide for improvement of power factor- consumers installations.

IS- 1646 : Code of practice for fire safety of buildings Electrical Installations.

IS- 3034 : Code of practice for fire safety of industrial buildings Electrical

generating and distributing stations.

OISD 113 : Classification of areas for electrical installations at hydrocarbon

processing and handling facilities.

OISD 173: Fire prevention and protection system for electrical installations.

OISD- 110: Recommended practices on static electricity.

IEC specifications shall be followed where equivalent Indian Standards are not available in

specific cases.

3.0 STATUTORY REQUIREMENTS:

The latest version of the following statutory regulations shall be followed for design ofelectrical system,

- Indian Electricity Act.

- Indian Electricity Rules.

- The Factory Act.

- The Petroleum Rules.

- Requirements of other statutory bodies as applicable, e.g. CEA, CCE,

DGFASLI, TAC

4.0 SYSTEM DESIGN PHILOSOPHY

4.1 General

The electrical system shall be designed to provide:

- Safety to personal and equipment both during operation and maintenance .

- Reliability of Service.

- Minimal fire risk.

- Ease of maintenance and convenience of operation.

PART IIISECTION 3


- Automatic protection of all electrical equipment through selective relaying system.

- Electrical supply to equipment and machinery with in the design operating limites.

- Adequate provision for future extension and modification.

- Fail safe feature.

- Suitability for applicable environmental factors.

- Maximum interchangeability of equipment.

4.2 Area Classification and Equipment Selection

4.2.1 All the areas with in the battery limits shall be classified for the degree and the extent

of hazard from flammable materials. Classification of hazardous areas shall be done in

accordance with Petroleum Rules, DGMS regulations (where applicable) and IS-

5572.

4.2.2 Following factors shall be considered for proper selection of electrical equipment for

use in hazardous area.

- Area classification i.e. Zone.

- Gas classification i.e. Group- The characteristic of the gas or vapour involved in

relation to the ignition current or minimum ignition energy and safe gap data.

- Temperature classification The ignition temperature of the gas vapour involved

or the lowest value of the ignition temperature if more than one combustible

material is present.

- Environmental conditions in which apparatus is to be installed The selected

electrical apparatus shall be adequately protected against corrosive and solvent

agencies, water ingress, thermal and mechanical stresses as determined by the

environmental conditions.

4.2.3 All electrical equipment installed in hazardous areas shall be selected as per IS- 5571

and shall meet the requirements of relevant IS, IEC or NEC Standards. However,

electrical equipments for Zone 2 areas as a minimum shall be ex (e)/ Ex (n) type as

per IS/IEC codes. Increased safety {Type Ex(e)} equipment shall not be used in Zone-

1 areas. Ordinary industrial electrical equipment (even though permitted for use in

Div.2 area as per NEC) shall not be used in Zone 2 areas. Type of explosion

protection to be used for individual equipment shall be as specified in the job design

data.

PART IIISECTION 3


4.2.4 For pressurised electrical equipment {Type Ex(p)}, on failure of pressurisation system

, the following minimum actions shall be provided:

Area classification Enclosure does not Enclosure contains ignition

Contain ignition capable apparatus.

Capable apparatus

Zone 1 Alarm Alarm and Switch- off.Zone-2 No action reqd. Alarm.

4.2.5 All electrical equipments for hazardous areas shall be certified by CMRI, PTB,BASEEFA, UL or FM or equivalent independent testing agency for the service and thearea in which it could be used and shall be approved by CCE/DGFASLI/DGMS (asapplicable). All indigenous flameproof equipment {Type Ex (d)} shall be under BISlicense.

4.2.6 Motors fed by frequency converters/variable frequency power supplies shall be tested

and certified along with the converter by an a appropriate agency.

4.3 Power System DesignThe distribution system shall be designed in accordance with project specification

taking into account all possible factors affecting the choice of the system to be adopted

such as required continuity of supply, flexibility of operation, operational costs,

reliability of supply from available power sources, total load and the concentration of

individual loads.

Special attention is drawn to chapter X of IE rules which includes requirements for

design of electrical system as applicable to oil mine installation under the

jurisdiction of DGMS.

4.4 Capacity of Electrical SystemAll the components of the electrical system shall be sized to suit the maximum

load, under the most severe operating conditions. Accordingly, the maximum

simultaneous consumption of power, required by continuously operating loads

shall be considered and an additional margin shall be taken into account for

intermittent service loads, if any. System design shall permit direct- on- line

starting of all motors unless specified otherwise.

The amount of electrical power consumed by each process unit shall be calculated

for its operation at the design capacity. As far as practicable, a switchboard for

essential services required for plant maintenance during extended period of shut

down, shall be provided.

PART IIISECTION 3


4.5 System Voltages

Voltage selection shall be based upon the following factors:

a) Size and location of loads.

b) Provision of future extension

c) Short circuit level

d) Availability of switch gear with suitable current rating and rupturing capacity

e) Possibility of keeping the number of different voltage levels to a minimum

f) Utilisation voltages for various equipment

g) Economics

The choice of voltages may also be affected by local regulations, standards, as well

as, the voltages of existing installations.

4.6 Voltage Drops

4.6.1 The maximum voltage drops in various sections of the electrical system under steady state conditions at full load shall be within the limits stated in the following table:

S.NO SYSTEM ELEMENTMAXIMUMPERMISSIBLEVOLTAGE DROP

a) Busduct or cable between transformer secondary andHV Switchboard or PCC/PMCC

0.5%

b) Cable between PCC/PMCC and MCC or auxillaryswitchboard.

i)MCC / Auxillary Switch board nearPCC/PMCCii) MCC / Auxillary Switchboard situated remotefrom PCC / PMCC.

0.5%

2 to 2.5%

c) Cables between HV Switchboard and HV Motor 3%d) Cable between PCC/ PMCC and motor. 5.5%e) Cable between MCC (situated near PCC/PMCC) and

motors.5%

f) Cable between MCC (situated remote fromPCC/PMCC) and motors

3%

g) Cable between Auxillary Switchboard & LightingPanel.

1 to 1.5%

h) Circuit between lighting panels and lighting points. 4%i) DC Supply Circuit (Electrical Controls) 5%j) DCDB to Control Room 2% (Note 1)k) UPS outgoing circuit 5% ( Note- 1)

Note 1 Minimum voltage available across any instrument in the field shall be as perInstrumentation design basis. Distribution system for instrumentation supplies shall be

PART IIISECTION 3


designed accordingly. In case of any conflict between electrical design basis andinstrumentation design basis, the later shall govern regarding instrumentation power supplies.

4.6.2 The maximum voltage drop at various buses during start up of large motor and / ormotor reacceleration conditions shall be with in the limits stated below:

S.NO SYSTEM ELEMENT OPERATINGCONDITION

MAX.PERMISSABLEVOLTAGE DROP

a) At the busbars of the worstaffected Switch board.

Start up of the large HVmotor with other loads onthe bus or reacceleration ofa group of HVmotors(Simultaneous startup or group reaccelerationof MV motors is notenvisaged)

15%

b) At the busbars of the worstaffected MV Switchboard.(PCC/PMCC/MCC)

Start up of large MVmotor with other loads onthe bus, or reaccelerationof a group of MV motors.

10%

c) Cables between HV Switchboard & motor.

Motors start up orreacceleration.

5%

d) Cables between MVswitchboard(PCC/PMCC/MCC) &motor.

Motor startup orreacceleration.

15%

NOTES:a) The voltage available at the motor terminals during start up must be sufficient to ensure

positive starting or reacceleration of the motor (even with the motor fully loaded, ifrequired), without causing any damage to the motor.

b) For medium voltage motors, the voltage available at the motor terminals must not be lessthan 75% of the rated value during startup or reacceleration.

c) For high voltage motors, the voltage available at the motor terminals must not be less than80% of the rated value during start up or reacceleration.

4.7 System Earthing

4.7.1 System earthing for incoming supply & primary / secondary / HV distribution system

shall be as per design data. The 415 V system neutral shall be solidly earthed.

4.7.2 For resistance earthed system, the resistance value shall be chosen to limit the earth

fault current to a value which shall be sufficient for selective and reliable operation of

heartfelt protection system, while ensuring minimum equipment damage during an

PART IIISECTION 3


earth fault. However, the value of limited earth fault current shall generally not exceed

50% of transformer or generator full load current.

4.8 Short Circuit CapacitiesEach short circuit interrupting device shall be designed to have rated service-

breaking capacity (Ics) equal to or higher than the maximum value of short circuit

current calculated, at is location. The related switchgear and busduct shall

withstand the above maximum available fault current for a minimum period of one

second. The sizing of high voltage cables shall be based on the short circuit

withstand capacity for a minimum time period as dictated by the protection system

in addition to the maximum anticipated load current.

4.9. Insulation System

The insulation of electrical facilities shall be designed considering the system voltage,

the system neutral earthling and the over voltages resulting due to system fault,

switching or lighting surges. The insulation coordination between the electrical

equipment and the protective devices shall be done in line with IS: 3716.

Lighting arresters ad surge absorbers shall be provided where necessary.

4.10 Protection and Metering Schemes

4.10.1 The protective system shall be selected and coordinated to ensure the following:

a) Protection of equipment against damage which can occur due to internal or external

short circuits or atmospheric discharges.

b) Uninterrupted operation of those parts of the system which are not affected by the

fault.

c) Personal and plant safety.

4.10.2 In general, quick acting relays (with time delays, if necessary) shall be used and all

fault tripping shall be done through high speed tripping relays. All relays, excepting

auxiliary relays and timers, shall be draw out type.

4.10.3 Metering instrument shall be provided to keep a record of power consumption and

supervision of all instrument shall be flush mounted back connected type.

PART IIISECTION 3


4.11. DC Power Supply

Independent DC Power supply systems shall be provided for the following:

- Plant shutdown system and DC instrumentation.

- Electrical switch gear controls and critical lighting.

- PLCC equipment.

- Emergency DC motors (if applicable)

- Telephone system

- Fire alarm system.

- Diesel engine starting (for each engine)

- Communication system (if applicable)

- Telecom & SCADA ( if applicable)

Each DC power supply system shall include charger -cum rectifier, dual float cumboost type, batteries and DC distribution board.

4.12. Emergency Power Supply

The emergency power supply system, where ever envisaged, shall feed the following:- Electrical loads essential for the safe shutdown of the plant.- Emergency lighting.- Process plant instrument as required.- Communication equipment.- Fire alarm system.- D.C Supply system.- UPS Systems.- Fire fighting equipment excluding main fire water pump.- Loads critical for process, plant and personnel safety.- Emergency power supply shall be made available within a time period of 30

seconds, from the instant of failure of normal supply.- The emergency generator shall, generally, not be required to run continuously

in parallel with the normal power supply system.

4.13 Uninterrupted Power SupplyUninterrupted power supply system shall be provided, (if required) for meeting criticalloads that cannot withstand a momentary interruption in voltage. A separate batteryshall be provided for UPS system. Following loads shall be connected to the UPSsystem.

- Critical instruments and control.

- Critical communication equipment.

- Critical security equipment.

- Computers.

- Annunciation panel.

PART IIISECTION 3


4.15 Plant Communication System4.15.1 It shall consist of the following:

- Micro processor based central exchange installed in the control room.

- Power supply system.

- Master station along with external loudspeaker, microphone etc.

- Desk type call stations along with microphone and external loudspeaker for

installation in buildings.

- Wall / column mounting type call stations for hazardous / safe areas with

external loudspeaker.

4.15.2. Paging speakers provided in areas having high ambient noise levels shall produce a

paging level at least 6dB above the anticipated ambient level. Field stations shall be

capable of operating in areas of high noise without any interference. Separate battery

and battery charger shall be provided for each exchange.

4.15.3. System shall have provision for addition of10% field call stations/ loud speakers in

future.

4.16 Fire Detection & Alarm System:

4.16.1 The Fire Detection & Alarm System shall be an independent system comprising ofindividual break glass type manual call points, automatic sensors e.g. smoke and heatdetectors, main panel, zonal panel, hooter, battery charger & other hardware. Thesystem shall be designed to provide audio visual indication at the main panel to belocated in fire station and zonal panel, in control room. Repeater panels shall beprovided as applicable.\

4.16.2. The manual call points shall be provided at strategic locations with access of 60mtrs.Along all exit routes & roads.

4.16.3. Battery and battery charger shall be provided for each panel separately.

4.16.4 Electrical sirens shall be provided at stragegic points to cover entire plant area.

4.16.5 Response indicators, hooters & exit lights shall be provided at required locations.

4.16.6 System shall have provision for addition of 10% detectors, manual call points in future.

4.16.7 The fire detection system shall be interfaced with fire suppression system; whereverrequired.

PART IIISECTION 3


5.0 EQUIPMENT DESIGN PHILOSOPHY

5.1 General

The equipment shall in generation conform to Standard specifications. Equipmentsshall be designed as per philosophy given below.

5.2 Transformers

5.2.1 All Transformers except lighting transformers shall be three phases, oil immersed,

double wound type suitable for outdoor use. Lighting transformers shall be dry type.

5.2.2 The rating of transformers shall be decided based on the following criteria:-

ONAN transformers:- The rating shall be equal to or higher than 110% of maximum

simulations demand envisaged.

ONAN/ONAF transformers:- The ONAN rating shall be equal to or higher than the

maximum simulations demand envisaged. The ONAF rating shall be equal or higher

than 125% Of ONAN rating.

5.2.3 The percentage impedance of each transformer shall generally be as per Indian

Standards.

5.2.4 100% standby transformers shall be provided in all unit, offsite & utility substations,

unless otherwise specified.

5.3 Switchgear

5.3.1 All switchgear and associated equipment fed from generators and transformers shall

have rating equal to the rating of respective generators and transformers feeding it,

under any circuit configuration. However, generator incomer shall be rated at least

equal to 110% of the continuous rating of generator and transformer incomer shall be

rated atleast equal to forced cooled rating of transformer or 110% of ONAN rating as

applicable.

PART IIISECTION 3


5.3.2 Bus tie circuit breakers shall have rating higher of the following:

a) Largest incoming circuit breaker.

b) Maximum running load on either side of bus section.

In no case shall the tiebreaker rating be less than the bus- bar current rating.

5.3.3 All other switchgears not directly fed from generator and transformers shall have

rating atleast equal to the maximum demand under any circuit configuration plus a

provision for 10% future load growth. Incomers of these switchgears shall be designed

to cater to the complete load including 10% margin for future load growth.

5.3.4 Spare outgoing feeders shall be provided in all switchgear. At least one number of

each rating and type or 20% whichever is more, shall be provided as spare.

5.3.5 Circuit breakers/ contactors controlling motor feeders shall have a rating of at least

125% of the maximum continuous rating of the connected motors.

5.3.6 Separate feeders shall be provided in the switch board for each load/ motor. However,

as an exception maximum two numbers welding receptacles may be connected to one

power feeder.

5.3.7 All circuit breakers shall be of single break type having one pole per phase. Circuit

breakers for MV generator incomer shall be with four poles. Alternatively three pole

breaker with adequately rated air break contactor for neutral isolation may be

provided.

5.3.8 In case of HV vacuum circuit breaker, adequate provision shall be made for motor

switching to limit the over voltage to 2.2 per unit of rated peak line to earth voltage.

5.3.9 Service breaking capacities (i.e. Ics) for all breakers & MCCB s shall be equal to or

higher than the maximum value of the short circuit at the point of installation. MCBB

s with back up fuses shall not be acceptable.

PART IIISECTION 3


5.3.10 Air circuit breakers (ACB) shall be provided in MV switchboards for all feeders rated

above 400 A and switchfuse units / MCCB s shall be provided for all feeders rated

upto 400A.

5.3.11 Circuit breakers/Switch fuse units for capacitors shall, have a current rating of at least

135% of the capacitor rated current. Circuit breakers capability to interrupt applicable

capacitive current shall be specifically verified.

5.3.12 The switchboard components viz. 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.

5.3.13 For motors above 5.5 KW, CT shall be provided in the switchgear for ammeter on the

local push button station. Indication lamp on the switchgear shall be LED type.

5.3.14 The maximum rating of bus bars for MCC s / ASB s / LDB s shall preferably be

limited to 800 Amps, Heavy-duty type load break switches / ACB shall be used for

incoming and tiebreakers and these shall have suitable interlocks.

5.3.15 The Auxiliary Service Board (ASB) and / or lighting distribution board containing

mainly switch fuse units shall have horizontal and vertical bus bars like those in PCC

& MCC.

5.4 Bus Duct

The rating of bus ducts connected to breakers shall have same continuous & short

circuit rating as that of breakers. Similarly bus ducts connecting to two bus sections

shall have same continuous & short circuit rating as that of main bus bars.

5.5 Neutral Grounding Resistor

Neutral Grounding Register (NGR) shall be housed in a sheet metal enclosure and

shall be naturally ventilated. The resistor shall be of unbreakable, corrosion proof

jointless stainless steel grids. The grids shall be in punched form. The NGR s shall be

rated to withstands the fault current for 10 seconds.

PART IIISECTION 3


5.6 Battery

Batteries shall be of adequate capacity to meet the back up requirements as envisaged

on the duty cycle as well as to take care of future load growth of 10%. While sizing the

battery, temperature correction factor and ageing factor shall be considered in addition

to the maintenance factor. Batteries shall be complete with battery racks and

accessories.

5.7 Battery Charger and Distribution Board

5.7.1 Charger and DB shall be floor mounted, free standing, metal enclosed and vermin

proof type having hinged door for front access and shall be suitable for indoor use.

The battery charger/rectifier shall feed the load and keep the batteries under fully

charged condition. Provision shall also be made for necessary boost charging/initial

charging of battery.

5.7.2 Each battery charger & DCDB shall have at least 10% spare capacity to meet future

requirements.

5.7.3 Each DCDB shall have at least 10% spare feeders for future use of owner.

5.8 Uninterrupted Power Supply System

5.8.1 The panels for UPS system shall be of floor mounted, free standing, metal enclosed

and vermin proof type having hinged door for front access and suitable for indoor use.

5.8.2 UPS system shall be sized to take care of the crest factor of the load current.

5.8.3 UPS system shall include a set of storage batteries, rectifier transformer, rectifier-

cum charger, inverter, set of filter circuit, static switches, bypass transformer, facility

for manual transfer between inverter supply and bypass line, facility for bypassing

inverter and static switch for maintenance, AC Distribution board and other associated

accessories.

PART IIISECTION 3


Under normal conditions, the rectifier- cum- charger shall feed the inverter and charge

the battery set. Incase of mains failure, the battery shall supply the necessary power to

the inverter. The inverter in turn shall feed the load through the static switch. If the

inverters malfunction or get overloaded, the load shall be instantaneously transferred

to the bypass line through the static switch. Normally, the inverter shall be operated in

synchronized mode with the bypass line, and manual forward transfer or manual

reverse transfer shall be effected without any break. Automatic forward transfer, in

case of inverter malfunction shall be affected with a break not exceeding 4

milliseconds.

5.8.4 Each branch circuit of the UPS distribution system shall have a fused disconnect

switch. The fuse shall be fast clearing type and the fuse rating shall be coordinated

with the rating of the UPS system. Normally the largest branch circuit load shall not

exceed 25% of the system rating.

5.8.5 Each UPS shall have at least 10% spare capacity to meet future requirements.

5.8.6 Each UPS ACDB s shall have atleast 10% spare feeders for future use by owner.

5.9 Motors

5.9.1 In general, three phase squirrel cage induction motors designed for direct on line

starting shal

Electrical Design

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