Ts110 Cable Standard for 66kv Underground Cable

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TS-110 - Cable Standard for 66kV Underground Cable

SA Power Networks.

TECHNICAL STANDARD TS-110

www.sapowernetworks.com.au

CABLE STANDARD FOR 66KV UNDERGROUNDCABLE

Published: 3 September 2012

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Issue: 03/09/12 Authorised by: J Ali Date: 03/09/12 Page 2 of 18

The use of this Technical Standard is subject to the conditions stated in SA Power Networks Disclaimer.

REVISION NOTICE

DATE EXPLANATION

Dec 08 New Document

3 September 2012Company name change only. No other content of this TechnicalStandard has been altered. Any revision markings are from theDecember 2008 edition.

SA Power NetworksSA Power Networks means Distribution Lessor Corporationsubject to a two hundred year lease to the partnership of companies trading as SA Power

Networks or SA Power Networks in its own right.

SA Power Networks, ABN 13 332 330 749, a partnership of:

Spark Infrastructure SA (No.1) Pty Ltd, ABN 54 091 142 380Spark Infrastructure SA (No.2) Pty Ltd, ABN 19 091 143 038

Spark Infrastructure SA (No.3) Pty Ltd, ABN 50 091 142 362

each incorporated in Australia

CKI Utilities Development Limited, ABN 65 090 718 880

PAI Utilities Development Limited, ABN 82 090 718 951

each incorporated in The Bahamas

1 Anzac Highway, Keswick, South Australia, 5035.

SA Power Networks Disclaimer:

1. The use of the information contained in this Technical Standard is at your sole risk.2. The information in this Technical Standard is subject to change without notice.3. SA Power Networks, its agents, instrumentalities, officers and employees:

a. Make no representations, express or implied, as to the accuracy of the informationcontained in this Technical Standard;

b. Accept no liability for any use of the said information or reliance placed on it; andc. Make no representations, either expressed or implied, as to the suitability of the

said information for any particular purpose.

4. SA Power Networks and its agencies and instrumentalities do not endorse or in anyrespect warrant any third party products or services by virtue of any information,

material or content referred to or included on, or linked from or to this Technical

Standard.

SA Power Networks Copyright @ 2012:

This publication is copyright. SA Power Networks reserves to itself all rights in such

material. You must not reproduce any content of this Technical Standard by any process

without first obtaining SA Power Networks permission, except as permitted under the

Copyright Act 1968.

All rights reserved.

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CONTENTS

CONTENTS ................................................................................................... 3

1.0 INTRODUCTION ............................................................................... 5

2.0

DEFINITIONS ..................................................................................... 5

3.0 DESIGNINFORMATION ................................................................. 5

3.1 CONTRACT DRAWINGS .......................................................................... 6

4.0 SERVICECONDITIONS ................................................................... 7

5.0 OPERATINGCONDITIONS ............................................................ 7

6.0 CABLECONSTRUCTION ................................................................ 9

7.0 CABLETESTS .................................................................................... 9

8.0

ELECTRICALACCESSORIES........................................................ 9

8.1 CABLE TERMINATIONS .......................................................................... 9

8.2 CABLE JOINTS ......................................................................................... 10

8.3 EARTHING ................................................................................................. 10

8.4 EARTHING AT TERMINAL POLE ....................................................... 11

8.5 JOINT BAY EARTHING .......................................................................... 11

8.6 SURGE ARRESTORS ............................................................................... 11

8.7

SURGE VOLTAGE LIMITERS (SVL) ................................................... 11

8.8 LINK BOXES .............................................................................................. 12

8.9 TERMITE BARRIER TAPE EARTHING .............................................. 12

8.10 FIBRE OPTIC CABLE .............................................................................. 12

9.0 FABRICATIONOFACCESSORIES ............................................. 12

9.1 GENERAL ................................................................................................... 12

9.2 SURFACE PROTECTION ........................................................................ 13

9.3 PAINTING .................................................................................................. 13

10.0 DELIVERYOFCABLEANDEQUIPMENT ................................ 13

11.0 INSTRUCTIONMANUAL .............................................................. 13

12.0 SUB-ORDERS ................................................................................... 15

13.0 INSTALLATION .............................................................................. 15

14.0 TESTSDURINGANDAFTERINSTALLATION ........................ 15

14.1 MEGGER TEST (BEFORE INSTALLATION) ..................................... 15

14.2 MEGGER TEST (DURING INSTALLATION) ..................................... 15

14.3 HIGH VOLTAGE TEST ........................................................................... 15

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14.4 OUTER SERVING HIGH VOLTAGE TEST ......................................... 15

14.5 MEGGER TEST (AFTER INSTALLATION) ........................................ 16

14.6 EARTH RESISTANCE TESTS ................................................................ 16

14.7 VERIFICATION OF SCREEN BONDING FOR CROSS-BONDED

ARRANGEMENTS .................................................................................... 16

14.8 CONDUCTOR AND SCREEN RESISTANCES .................................... 16

14.9 SURGE VOLTAGE LIMITERS (SVL) ................................................... 16

14.10POSITIVE AND ZERO PHASE SEQUENCE IMPEDANCE .............. 16

14.11INDUCED VOLTAGE ON CABLE SCREEN ........................................ 16

15.0 DEFECTSLIABILITY ..................................................................... 16

16.0 APPENDICES......................................................................................... 17

16.1 APPENDIX A: TYPICAL INSULATOR PROFILE .............................. 17

16.2

APPENDIX B: TYPICAL OVER/UNDER POLE ARRANGEMENT . 18

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1.0 INTRODUCTION

This standard sets out the design, manufacturing, delivery, jointing, terminating and

commissioning requirements for 66kV Underground Cables.

The installation of the cable shall be in accordance with Technical Standard TS-085

- Civil Works Standard for Underground Cables.

2.0 DEFINITIONS

SA Power Networks means:-

SA Power Networks, ABN 13 332 330 749, a partnership of:Spark Infrastructure SA (No.1) Pty Ltd, ABN 54 091 142 380



each incorporated in Australia

CKI Utilities Development Limited, ABN 65 090 718 880

PAI Utilities Development Limited, ABN 82 090 718 951

each incorporated in The Bahamas

1 Anzac Highway, Keswick, South Australia, 5035.

3.0 DESIGN INFORMATION

SA Power Networks will supply specification information relating to the cable.

The information to be provided will include the following;

Conductor size

Continuous summer rating

Method of cable installation Nominal circuit length (allowances to be made by SA Power Networks for

joint overlaps)

Conduit requirements

Circuit route with suggested joint bay locations

Drawing A1-DH1625Pole top termination support if applicable

Purchasing guidelines in accordance with AS/NZS 1429.2 Appendix B

Spare equipment requirements

Substation sealing end support structure drawing if applicable

Terminal pole sealing end support structure

Joint locations and approximate drum lengths shall be determined by SA Power

Networks. The contractor shall familiarise themself with local conditions in

relation to joint location with regard to avoiding road intersections, existing buried

services etc. and would cause the least disruption to road traffic.

Whilst suggested joint locations are shown on the purchasers drawings, the

contractor is free to offer drum lengths and joint locations as they see fit. However,

joint bay locations will require the approval of SA Power Networks.

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Within six weeks of the date of an order the contractor shall submit details of their

designs for the cable installation. These details shall include a drawing to show the

electrical design, and a complete list of the materials required for the installation.

Designs must adhere to the requirements of all relevant SA Power Networks E-

Drawings and specifications, in particular:

E1510 66kV Over/under TerminationEarthing Arrangement E1545 66kV Over/under Arrangements

3.1 CONTRACT DRAWINGS

Within three months of the date of an order three copies of each contract

drawing shall be submitted to SA Power Networks for approval. For

equipment made outside Australia, a further copy of each drawing shall be

supplied to SA Power Networks.

All of the following drawings shall be submitted:

1. General arrangement of the cable system including:

detailed earthing system including sheath bonding;

joint bays;

detailed conduit plan including size and layout;

trench cross section showing depth and spacing requirements;

any other drawing appropriate to the installation theequipment.

2. A detailed general arrangement drawing and material list for each

accessory, including, but not limited to:

outdoor sealing end and support structure dimensionalrequirements;

each type of joint;

each type of link box i.e. joint bay and sealing end types;

cable screen surge diverter;

each type of special tool or die;

link box and covers.

All arrangement drawings shall be drawn to scale.

The drawings shall be modified by the contractor as required by SA Power

Networks and resubmitted for final approval.

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4.0 SERVICE CONDITIONS

The thermal rating of all equipment shall be based on the service conditions

detailed in this specification.

The plant shall be suitable for operating continuously under the following ambient

conditions with particular attention being paid to the performance of the sealing

ends:(a) Altitude

Less than 1000 m above sea level

(b) Ambient air shade temperatures

Maximum 50oC

Maximum 24 hour average 40oC

Minimum -5C

Frequent rapid drops in temperature give rise to condensation in enclosed

compartments.

(c) Solar radiation

Maximum on horizontal surface 1.1 kW/m2

(d) Wind loading (Reference AS/NZS 1170.2)

Basic design velocity 50 m/s

Terrain category 1

5.0

OPERATING CONDITIONSThe cable system will be part of SA Power Networks66 kV distribution system

and in particular will form the underground portion between the locations as

specified.

SA Power Networksdistribution system generally utilises a solidly earthed neutral

however, small neutral reactors or resistors may be introduced in the future.

System characteristics are detailed in the following table.

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Table 1Cable Operating Conditions

Details of System

System nominal voltage 66kV

System highest voltage 72kV

Frequency 50Hz

Number of phases 3System neutral solidly earthed, or earthed through a small

resistor or reactor for future system

configurations

Fault conditions

- fault current (3 phase or single Phase) 31.5kA

- fault clearing time 1.0 second

Details of Cable Installation

Power Cables

Rated voltage 66kV

Rated throughput (per circuit, summer

continuous)

MVA, to be advised

Nominal route length metres, to be advised

Insulation levels

- power frequency withstand (core-sheath) 95kV (rms) for 24 h

- lightning impulse withstand 325kV (p)

Thermal resistivity C m/W

- soil (maximum) 1.2

- "controlled bedding" (maximum) 1.2

- sand backfill material (maximum) 1.2 with 5% moisture

Intensity of solar radiation 1.1kW/m

Soil temperature

- winter 15oC

- summer 25oC

Cable construction

- type of cable tree retardant cross linked polyethylene

- conductor copper

- number of cores single core

- screen (XLPE cables) stranded copper

- anti-termite tapes stainless steel or brass

Maximum conductor temperature

- under continuous full load conditions 90C

- under fault conditions (1.0s)

- conductor 250C

- screen 160C (A higher temperature may be

permitted based on the outer sheath material)

Terminations to be specified by SA Power Networks

(Outdoor or indoor)

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6.0 CABLE CONSTRUCTION

The cable shall be XLPE insulated, 66kV three phase (3 x single core) in

accordance with this standard.

The construction shall comply with the requirements of AS/NZS 1429.2. The

moisture barrier shall be lead alloy E sheath, corrugated stainless steel or

corrugated aluminium.The insulation, sheath and serving materials shall be selected and proportioned such

that the thermal and mechanical conditions, during a fault shall not give rise to any

deterioration.

Protection against subterranean termite attack shall be provided. A continuous

extrusion of black PVC compound, or similar material, shall be applied over the

screen to form a bedding for termite protection tapes. The thickness of the bedding

shall be sufficient to provide a smooth profile for the application of the protective

tapes, prevent contact between these tapes and the sheath during manufacture and

handling at site, and withstand a 5 kV dc l minute test between the tapes and the

screen after laying. The tapes for protection against termites shall be of non-magnetic stainless steel or brass and consist of two layers, wound so that each layer

fully covers the bedding with 50% overlap. Each tape shall have a minimum

thickness of 0.1 mm, and be electrically continuous. At each joint position a

connection shall be made to the anti-termite tapes and brought out to the earthing

link box for testing purposes. The non-metallic sheath shall comprise a compound

of ultra-violet stabilised high density polyethylene (HDPE).

Meter marking on the cable sheath shall be provided.

7.0 CABLE TESTS

The cable shall be tested in accordance with AS/NZS 1429.2. Test certificates arerequired to be submitted for all tests performed on the equipment prior to the

delivery of cables.

For type tests, a test assembly shall be prepared. This shall include at least 20m

total length of cable between accessories, terminations and joints of the types

proposed for the contract installation. The cable shall include a length which has

been subjected to the bending test.

8.0 ELECTRICAL ACCESSORIES

8.1 CABLE TERMINATIONS

Silicon compound terminations are the preferred termination type. Porcelainterminations maybe specified where silicon compound terminations are not

suitable eg. areas of high bird activity. Terminations must comply with the

ratings stated in this standard and any specifications issued by SA Power

Networks. All terminations will generally be in accordance with AS/NZS

60137.

Refer to Distribution Engineering Standards branch for approved 66kV

terminations for use on the SA Power Networks network.

Contractors shall submit with their offers fully dimensioned drawings of the

terminations and showing the complete profiles. The drawings shall show the

working stress levels (kV/mm) in all critical areas.

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The external creepage distance over the termination shall be not less than

1380 mm.

Each outdoor sealing end shall be fitted with a tinned copper or gunmetal

terminal palm dimensioned in accordance with palm terminal No 5 of AS

62271.301 and an earth terminal clamp suitable for connection of a 185 sq

mm copper conductor earthing cable.

Attention shall be paid to connections between dissimilar metals. The

Each sealing end shall be supplied with an insulating base using porcelain

stand-off insulators capable of withstanding for one minute a test voltage of

15 kV dc.

Contractors shall describe the cable terminating methods in outline, and

provide a list of any special tools required for the proposed method.

Terminal poles and substation structures will be supplied and erected by SA

Power Networks. A suitable sealing end support structure will be supplied

and erected on poles by SA Power Networks. The Contractor shall be

responsible for mounting, terminating and clamping the cables, earthing andfor the supply and fitting of a 3m high galvanized steel cable guard at the base

of the pole. Refer E1510 series and drawing A4-4111/00/034 in Appendix B.

Note: Cables shall be installed on the pole so they are facing away from

oncoming traffic.

Terminations shall be filled with an insulating fluid compatible with the cable

materials.

Stress cones may be of the pre-moulded rubber type.

8.2 CABLE JOINTS

Cable joints shall be suitable for direct burial in backfilled joint bays.

Contractors shall include details of the protective coatings applied over joints

to provide sheath/screen insulation and protection from corrosion. The

insulation shall be at least equal to that of the cable serving. Where "coffins"

are used the halves shall be secured together using bolted flanges.

Contractors shall provide drawings of each joint and an outline of the jointing

method. The drawings shall show the working stress levels (kV/mm) of all

critical areas.

8.3 EARTHING

SA Power Networkssystem incorporates a common, multiple earthed, highand low voltage neutral.

SA Power Networks will specify whether a single point bonded or cross

bonded sheath/screen earthing arrangement will be used. Refer E1510 series

for varying earthing arrangements.

The Contractor shall describe in detail, with drawings, the arrangements

proposed to use for bonding and earthing of the complete cable systems and

shall include calculations of sheath voltages and, (where cross-bonding is

used) circulating currents.

The cable earthing arrangement shall be designed to ensure that, undernormal conditions, the sheath voltage will not exceed 65 V ac rms at any

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point in the installation and that sheath losses due to circulating currents are

minimized. Where cost-effective, SA Power Networks will consider designs

that have sheath voltages higher than 65volts, but, these designs must be

submitted for approval by ETSA. It shall withstand the transient overvoltages

and 50 Hz ac fault currents required in this specification.

Earthing cables shall be insulated and have a 185 mm2minimum cross

section copper conductor.

All joints and earth stake connections shall be fully sealed against ingress of

moisture.

8.4 EARTHING AT TERMINAL POLE

The maximum value of earth resistance at each over/under pole shall be 5

ohms (in dry conditions when link to overhead CMEN conductor and

underground cable is temporarily disconnected). Earth electrodes must be

connected if the footing alone is more than 5 ohms. If the required resistance

can not be achieved with four electrodes then refer to SA Power Networks for

further consideration.Earthing electrodes shall be stainless steel clad mild steel of not less than 12

mm diameter.

8.5 JOINT BAY EARTHING

An earthing electrode system shall be provided at each joint bay and shall

comprise as a minimum an earth stake in each corner of the bay. The

maximum value of earth resistance at each earthing location shall be 5 ohms.

Link box casing, the common neutral earthing conductor and frames and

supports of any other ancillary equipment shall be connected to the joint bay

earthing system.8.6 SURGE ARRESTORS

Surge arresters are to be installed at each termination to protect the

underground cable. These are to be mounted on the same support structure as

the terminations. Refer to SA Power Networks E drawing series E1510. The

earthing arrangements for both the termination and surge arrester can also be

seen on these drawings.

Surge arrestor taps shall be kept as short as possible (refer E1510 sheet 2.2).

Only surge arrestors approved by SA Power Networks shall be used.

8.7 SURGE VOLTAGE LIMITERS (SVL)The cable sheath insulation shall be protected against impulse, switching

surge and 50 Hz overvoltages resulting from cable or system faults by sheath

surge diverters utilising Zinc Oxide elements. Constructional and electrical

details shall be included in the tender.

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8.8 LINK BOXES

Cross bonding of cable sheaths shall be affected using waterproof link boxes

located in pits on the footpath adjacent to the joint bay or on sealing end

structures where applicable.

At the Over/Under poles earth links shall be mounted on the pole above the

cable guard in a suitable weatherproof box at a minimum height of 3.6mabove ground level (refer E1510 Sheet 5). Refer to cable manufacturer for

suitable link box with suitably rated earth bar (refer Table 1).

Where link box case and lid are fabricated from ferrous material they shall be

hot-dipped galvanized after fabrication. If made from other non-corrodible

material e.g. stainless steel, no further surface protection is necessary.

Disconnecting link support insulators shall withstand 15 kV dc for one

minute. Links shall be of tinned copper and clearly labelled (on each side of

the link) with the phase identification "X", "Y" and "Z". A durable label shall

be fixed to each link box lid showing a diagram of the link connection

arrangement.The metallic link box casing shall be connected to the joint bay or sealing end

earthing electrode system.

Where surge voltage limiters (SVL) are installed in the link box, the 66kV

surge arrestor earth connection shall be directly bonded to the earth bar (refer

E1510 Sheet 3.1).

8.9 TERMITE BARRIER TAPE EARTHING

Termite barrier tapes shall be earthed through insulating links to facilitate

testing of screen insulation.

8.10 FIBRE OPTIC CABLE

Where fibre optic cable is included, it shall be terminated in a suitable

junction box below the termination frame unless otherwise specified.

Note: Do not bend the fibre optic cable below minimum bending radius (refer

to cable manufacturer for details of specific cable).

9.0 FABRICATION OF ACCESSORIES

9.1 GENERAL

The equipment shall be entirely suitable for continuous operation under the

conditions specified herein and shall include everything necessary for safeand convenient installation, operation and maintenance.

The equipment (excluding the cable itself) shall be designed to carry short-

term load current of up to 150% of the continuous summer rating for periods

of up to four hours.

The equipment shall be so constructed that:

(a) it is not affected by normal handling during transport, installation,

inspection and repair,

(b) maintenance can be carried out conveniently and safely,

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(c) the design, materials and dimensions of all parts are such that the

stresses to which they are subjected shall not render them liable to

distortion or damage, under the most severe operating or fault

conditions likely to be encountered in service.

9.2 SURFACE PROTECTION

Except where otherwise stated, all metallic surfaces shall be given protectivecoatings.

The Purchaser prefers the use of non-corrodible materials.

Where practicable all ferrous metal external surfaces shall be galvanized.

9.3 PAINTING

Where applicable, paint work shall be in accordance with AS 2312"Guide to

the Protection of Iron and Steel Against Exterior Atmospheric Corrosion",

unless otherwise specified herein.

Non-ferrous metal surfaces to be paint finished shall be prepared for painting

by decreasing in accordance with AS 1627.1.

10.0 DELIVERY OF CABLE AND EQUIPMENT

After testing at works every length of cable shall be sealed. The cable shall bedespatched on substantial drums which will adequately protect the cable during

transport and site handling. The cable drum shall be arranged to take a round

spindle and shall be fitted for shipment with strong closely fitting battens to prevent

damage to the cable. Spare parts shall be crated separately.

Each crate shall be marked with:

Purchaser's name

Delivery point

Purchaser's specification, item and order numbers

Manufacturer's serial number

Crate number

Gross mass

In addition, each cable drum shall be marked with:

The section of the route to which the particular drum applies (Section A B)

An arrow indicating the direction of rolling

The length of cable

The cable voltage and size

11.0 INSTRUCTION MANUAL

The Contractor shall supply to the Engineer, before the first delivery of the

equipment, four copies of an instruction manual giving all the information

necessary for the installation, commissioning, operation and maintenance of each

portion of the equipment.

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Each manual shall relate solely to the equipment supplied, and shall not contain any

material which is not applicable to this equipment.

The manuals shall be suitable for accepting A4 size sheets and all drawings shall be

suitably folded or photographically reduced for convenient filing in the manual.

Within three months after the date of an order a draft instruction manual shall be

submitted for approval.The equipment shall be considered substantially incomplete for the purpose of

payment until the approved copies of this manual have been received.

Each instruction manual shall comprise the following:

A cover suitable to withstand normal field handling

A comprehensive index of all material in the manual

A description of the cable system

A summary of all electrical parameters and the performance data of the cable

system. Calculations of the electrical design, cable ratings and sheath induced voltages.

A general description followed by a detailed technical account of the operationof each portion of the equipment. This shall include the drawings, diagrams,

graphs, and photographs needed to ensure clarity.

A copy of each type and routine test certificate and report.

A copy of the results of all tests made after delivery and installation.

A sketch showing thermocouple locations and formulae and graphs to computethe conductor temperature from the serving temperature.

Information on the inspection, testing, installation and maintenance of allequipment. This shall include:

Instructions for installing each item of equipment and material. Theseshall include detailed cable jointing and terminating instructions.

The instructions required to dismantle and assemble each item ofequipment, where appropriate.

A schedule of the tests, adjustments, replacements and other workrequired to maintain correct performance.

Values, with permissible tolerances, to be achieved in the scheduledtests and adjustments.

Maintenance procedures during service.

Any other information that the Contractor considers to be useful orrelevant to the particular installation.

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12.0 SUB-ORDERS

The Contractor shall provide one copy of any sub-order placed for:

Castings

Welding assemblies

Bushings and insulators

Protective and measuring equipment, and

Any other major sub-assembly

Each sub-order copy shall be provided immediately after it is prepared.

If the equipment is manufactured outside Australia, one additional copy of each

sub-order shall be provided.

Each sub-order shall state that the work is subject to the requirements of this

specification, as amended by approved departures, and shall be marked with:

The number of the specification

SA Power Networks order number

13.0 INSTALLATION

The Contractor is completely responsible for the, supply, installation, testing and

commissioning of the cable system as specified in the contractual arrangements.

SA Power Networks is prepared to purchase appropriate special tools and

equipment used by the Contractor for the jointing and terminating of the cables

provided that they are in a satisfactory condition.

The Contractor shall list the tools and equipment available for purchase in theprices schedule.

14.0 TESTS DURING AND AFTER INSTALLATION

14.1 MEGGER TEST (BEFORE INSTALLATION)

A Megger test of each core and each screen is to be carried out while still on

the drums after delivery if the ends are accessible.

14.2 MEGGER TEST (DURING INSTALLATION)

A Megger test of each core and each screen is to be carried out when it is laid

in the trench or conduit and before the terminations are commenced.

14.3 HIGH VOLTAGE TEST

The cable system shall be subjected to power frequency withstand test for 24

hours.

14.4 OUTER SERVING HIGH VOLTAGE TEST

The outer serving of each section between joints shall be subjected to 10 kV

dc for 1 minute and have an acceptable leakage current.

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16.0 APPENDICES

16.1 APPENDIX A: TYPICAL INSULATOR PROFILE

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16.2 APPENDIX B: TYPICAL OVER/UNDER POLE ARRANGEMENT

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Ts110 Cable Standard for 66kv Underground Cable

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