engineering commissioning procedurelibrary.ukpowernetworks.co.uk/library/asset/201b0d2b...visual...

Document Number: ECP 11-0006

Version: 11.1

Date: 16/05/2018

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ENGINEERING COMMISSIONING PROCEDURE

ECP 11-0006

HV INSULATION TESTING

Network(s): All

Summary: This standard details the policy for the on-site insulation testing of new and existing high voltage cables, switchgear and transformers.

Author: Stephen Tucker Date: 16/05/2018

Approver: Paul Williams Date: 09/07/2018

This document forms part of the Company's Integrated Business System and its requirements are mandatory throughout UK Power Networks. Departure from these requirements may only be taken with the written approval of the Director of Asset Management. If you have any queries about this document please contact the author or owner of the current version.

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HV Insulation Testing Document Number: ECP 11-0006

Version: 11.1

Date: 16/05/2018

© UK Power Networks 2018 All rights reserved 2 of 18

Revision Record

Version 11.1 Review Date 10/02/2022

Date 20/08/2018 Author Stephen Tucker

Reason for update: Review following feedback from field staff on the back of a cable failure.

What has changed:

11-33kV cable sheath testing requirements clarified (Section 5.3.3).

66kV and 132kV XLPE cable partial discharge test requirements added (Section 5.4.2).

66kV and 132kV cable fault location test requirements added (Section 5.4.3).

66kV and 132kV cable sheath test requirements added (Section 5.4.4).



Reason for update: Review following feedback from field staff on the back of a cable failure.

What has changed:

Section 5.4 - Updated to provided further clarification of when an over-sheath test is required.

Section 5.5 - Requirement to record test results on ECP 11-006a added.

Section 5.6 - Requirement to carry out a PD test and all test results to be recorded on ECP 11-0006a added. Clarification added to the type of ac voltage to be applied.



Reason for update: Alignment with other referenced documents.

What has changed:

Document references updated (Sections 11and 12).

Test form references updated (ECP 11-0006a).



Reason for update: Renumbered to align with other commissioning documents and new cable insulation test form ECS 11-0006a added.

What has changed:

Document renumbered from EOS 09-0001 to ECS 11-0006.

HV polymeric cable sheath testing document reference updated (Sections 5.4 and 5.9).

New test form ECS 11-0006a added to record cable insulation test results (Section 11).


Date 21/03/2014 Author Paul Dyer/Paul Williams

Review and additional clarifications added

Version 7.0 Review Date

Date 21/02/2011 Author Paul Williams

Clarification for cable sheath test requirements added


Date 20/10/2010 Author Mariann Mulligan

Document rebranded


Version: 11.1

Date: 16/05/2018



Date 10/03/2009 Author Paul Williams

Revision to test voltage for 66 and 132kV cables


Version: 11.1

Date: 16/05/2018


Contents

1 Introduction ............................................................................................................. 6

2 Scope ....................................................................................................................... 6

3 Glossary and Abbreviations ................................................................................... 7

4 Testing ..................................................................................................................... 7

4.1 General ..................................................................................................................... 7

4.2 New Apparatus .......................................................................................................... 8

4.3 Existing Apparatus..................................................................................................... 8

4.4 Test Application ......................................................................................................... 8

4.5 Test Methods ............................................................................................................. 8

5 Cable Testing ........................................................................................................... 9

5.1 Acceptable IR Values ................................................................................................ 9

5.2 Switchgear Associated with Cable Testing ................................................................ 9

5.3 Cables up to 33kV ..................................................................................................... 9

5.3.1 New and Existing Cables – up to 33kV ...................................................................... 9

5.3.2 Cable Fault Location – up to 33kV ........................................................................... 10

5.3.3 Cable Over-sheath Tests – 11kV to 33kV Cables .................................................... 10

5.4 66kV and 132kV Cables .......................................................................................... 11

5.4.1 New and Existing Cables – 66kV and 132kV Oil and Gas Pressure Assisted Cables ..................................................................................................................... 11

5.4.2 New and Existing Cables – 66kV and 132kV Cables Containing XLPE Insulated Cable ................................................................................................................................ 11

5.4.3 Cable Fault Location – 66kV and 132kV .................................................................. 12

5.4.4 Cable Over-sheath Tests – 66kV and 132kV Cables ............................................... 12

6 Switchgear Testing ................................................................................................ 13

6.1 Test Voltages .......................................................................................................... 13

6.1.1 New switchgear ....................................................................................................... 13

6.1.2 Existing switchgear .................................................................................................. 13

6.1.3 Application of Test Voltage ...................................................................................... 13

6.2 Alternative Soak Test for 66kV and 132kV GIS Switchgear ..................................... 15

6.3 Air Insulated Busbars and Disconnectors ................................................................ 15

7 Transformer Testing .............................................................................................. 16

8 Transformer Tails and Test Access ..................................................................... 17

9 Overhead Line Testing .......................................................................................... 17

10 Other Equipment ................................................................................................... 17

11 Test Results ........................................................................................................... 17

12 References ............................................................................................................. 18


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12.1 UK Power Networks Standards ............................................................................... 18

12.2 National and International Standards ....................................................................... 18

13 Dependent Documents.......................................................................................... 18

Tables

Table 5-1 – Minimum Test Voltages for New and Existing Cables up to and including 33kV . 9

Table 5-2 – Maximum Voltage Levels for Fault Location for Cable up to and including 33kV .................................................................................................................. 10

Table 5-3 – Cable Over-sheath Test Voltages for Cables up to 33kV .................................. 10

Table 5-4 – Minimum Test Voltages for New and Existing Fluid and Gas Filled 66kV and 132kV Cables .................................................................................................... 11

Table 5-5 – Minimum Test Voltages for New 66kV and 132kV XLPE Cables ...................... 11

Table 5-6 – Minimum Test Voltages for 66kV and 132kV Cable Containing Existing Sections of Cable ............................................................................................................. 12

Table 5-7 – Maximum Voltage Levels for Fault Location for 66kV and 132kV Cable Systems ............................................................................................................. 12

Table 5-8 – Cable Over-sheath Test Voltages for Cables – 66kV and 132kV ...................... 12

Table 6-1 – Test Voltages for New Extensible Switchgear .................................................. 14

Table 6-2 – Test Voltages for Existing Switchgear .............................................................. 14

Table 7-1 – Test Voltages for Transformers ........................................................................ 16

Table 7-2 – Maximum Test Voltages for Transformers (for example where other equipment is connected) ..................................................................................................... 16


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1 Introduction

This standard details the requirements for the on-site insulation testing of high voltage cables, switchgear and transformers. The purpose of on-site insulation testing is to demonstrate that apparatus can be safely connected to the system.

The testing regime detailed in this standard is designed to avoid unnecessary overstressing and to prolong the life of the apparatus. It should identify any gross defect, damage or earths left connected at a remote end. The testing regime is based on current practice from the relevant British and International standards together with current practice used on the three networks within UK Power Networks. Consideration has been given to safety of field staff, the availability of test equipment and the relative merits of ac, dc, oscillating wave (OWTS) and very low frequency (VLF) ac testing.

This standard supersedes the following documents:

EPN: EDM V12/S1/8 – Site Insulation Tests for High Voltage Equipment.

LPN: E5-6-1 – Dielectric Testing.

LPN: E5-6-1-1 – HV Dielectric Testing.

SPN: EI 9-001-12 – Site Insulation Testing of Cables, Switchgear and Transformers.

SPN: Site Testing & Commissioning Manual – 2.N3 – On-site Insulation Testing of Cables, Switchgear & Transformers.

2 Scope

This standard applies to the insulation testing of cables, switchgear and transformers from 1000V to 132kV on the EPN, LPN, SPN and private networks and includes:

New apparatus before it is connected to the system for the first time.

Existing apparatus after it has been modified, repaired or moved.

Existing solid cable after it has been de-energised for an extended period.

Cable fault locating.

The testing of insulated cable sheaths.

Overhead lines where insulation testing is not considered practicable.

This standard does not seek to provide condition monitoring information or partial discharge information.


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3 Glossary and Abbreviations

Term Definition

GIS Gas Insulated Switchgear

IR Insulation Resistance

NVD Neutral Voltage Displacement

OWTS Oscillating Wave Test Set

SAP Senior Authorised Person

VLF Very Low Frequency

UK Power Networks UK Power Networks (Operations) Ltd consists of three electricity distribution networks:

Eastern Power Networks plc (EPN).

London Power Network plc (LPN).

South Eastern Power Networks plc (SPN).

4 Testing

4.1 General

Testing shall be carried out:

After apparatus is installed (or re-installed) but before energisation for the first time.

After work on the insulation of apparatus but not normally after routine maintenance.

After cable with solid insulation has been intentionally left de-energised for more than one month.

For new and re-commissioned equipment the interval between testing and energisation from the system should be the minimum practicable:

Cables up to and including 11kV no more than 24 hours.

Cable systems from 22kV and up to and including 132kV this should normally be no longer than 72 hours.

However for cables at all voltages an extension to this period is available to the Senior Authorised Person (SAP) providing the integrity of the system can be assured, for example visual inspection of the route or the completion of another successful sheath test.

Swinger transformers and other standby equipment that is left intentionally de-energised will need to be energised monthly to avoid the need for isolation and testing.

Dispensation to vary from the test methods and voltage levels set out in this standard for network test voltages above nominal phase to earth voltages can be granted by the UK Power Networks’ Technical Sourcing and Standards Manager. Where the network test voltage is lower than the nominal phase to earth voltage, permission to test should be sought from the Director of UK Power Networks Asset Management.


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4.2 New Apparatus

All new apparatus should, following installation, be successfully tested once at the voltage specified in this standard. Where the manufacturer recommends tests that differ from this standard, guidance shall be obtained from UK Power Networks Asset Management.

4.3 Existing Apparatus

All apparatus which has been de-energised and has knowingly had the insulation affected (except changing oil and topping up SF6) shall be subjected to an insulation test as specified in this standard.

4.4 Test Application

Where two or more items of apparatus are connected, the apparatus requiring the least onerous test determines the test voltage.

Site engineers shall take account of the risks involved in disconnecting equipment compared with the risks of a reduced voltage test. Equipment installed to run initially at a lower voltage than its rating shall be tested according to its rating before connection to the lower voltage system. If, after this test, the insulation is in any way disturbed, e.g. a 33kV cable is jointed to an 11kV cable, an insulation test voltage appropriate to the working voltage shall be applied before commissioning.

4.5 Test Methods

This standard includes both dc and ac test methods. A dc test is usually carried out using an insulation tester with the appropriate voltage output, such as a Megger or dc pressure test set. An ac test is usually carried out using an ac test set, OWTS test set or a test van to give the required voltage. Where both dc and ac tests are specified for equipment or cables either test may be used.

For cables it is necessary to apply the test voltage and allow the cable to fully charge up. Generally with test sets the timing begins when the test set has reached the required voltage and for insulation resistance (IR) testers the time begins when the IR value has stabilised.

Also, with some newer IR test sets, the test is considered a pass if the cable remains at the specified voltage for the duration of one minute – the voltage will drop if the insulation breaks down during that time span.

Partial discharge testing methods are being developed and operational advice will need to be followed.


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5 Cable Testing

5.1 Acceptable IR Values

It is not possible to specify a lowest acceptable insulation resistance value for dc testing (as it depends on a number of factors including cable type/length, weather conditions, etc.) all three cores should be similar and a different value on one core would indicate a problem.

The determining factor is whether any of the phases has an unacceptably low reading (1MΩ) or a drastically different reading. Engineering judgement needs to be applied to the value obtained. If traditional fault location fails to indicate a fault then connecting the circuit to the network for a 24 hour soak test is acceptable. If customers will be affected by the fault occurring during this test the number of customers shall be as low as is reasonably practical.

5.2 Switchgear Associated with Cable Testing

It shall be established whether the switchgear is capable of withstanding the cable test voltage, otherwise, the least onerous test voltage shall be used.

Note: The specification for new switchgear ensures that all cable test access points will withstand the highest cable

test voltages detailed in this document.

5.3 Cables up to 33kV

5.3.1 New and Existing Cables – up to 33kV

It is essential before energisation to ensure the cable is continuous from end-to-end. This will check that the cable is laid as planned and that any route joints have been completed.

Table 5-1 shows the minimum voltages to be used. Voltages up to those detailed in Table 5-2 are acceptable if site conditions require. These voltages can also be used for testing transformer tails between the winding and earth; refer to Section 8.

Table 5-1 – Minimum Test Voltages for New and Existing Cables up to and including 33kV

Rated Line Voltage (kV)

Cable Type

dc Test Test Application

Voltage (kV)

Duration (min)

6.6 (2 and 3.3)

All Types

5

1

Test voltage applied to one phase with the other two phases connected to earth/metallic screen

Test voltage may also be applied to two phases with the third connected to earth/metallic screen

11 All Types

See note

20 and 22 All Types

33 All Types

Note: Partial discharge mapping carried out in London, mainly at 11kV, is used as a commissioning test. These

tests require the test voltage to be of the order of 1.5Uo ac at 0.1Hz for a period of up to 15 minutes.


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5.3.2 Cable Fault Location – up to 33kV

It is permissible to apply higher dc voltages for fault location up to the maximum shown in Table 5-2.

Table 5-2 – Maximum Voltage Levels for Fault Location for Cable up to and including 33kV

Rated Line Voltage (kV) dc Test Voltage (kV) to Earth

6.6 7

11 12

20 and 22 24

33 36

5.3.3 Cable Over-sheath Tests – 11kV to 33kV Cables

The test voltages for over-sheath tests are given in Table 5-3. All cable over-sheath tests shall be carried out as specified in ECP 11-0007. These tests shall be applied under the following circumstances:

For all new cables (having an insulated sheath):

o After the cable drum has been off loaded from the delivery vehicle, visually inspected and checked; and before the cable is pulled in.

o After the cable has been installed (either direct buried or ducted). o After the complete circuit has been jointed and prior to energisation.

When returning an insulated sheath cable to service following diversion or repair.

Note: All drums should have been sheath tested in the factory before shipment and the onsite values should be

compared to these. If damage is found during the initial visual inspection, it should be photographed and the supplier shall be contacted, prior to the cable being sheath tested and installed.

Table 5-3 – Cable Over-sheath Test Voltages for Cables up to 33kV

System Nominal Voltage (kV)

Minimum dc Test Voltage (kV)

New cables

Minimum dc Test Voltage (kV)

On return to service

Test Duration (min)

Maximum Leakage Current (mA)

Test Application

11

5

Not Applicable

1 10

Between metallic sheath and earth

20 and 22

5

33 5

Note: Specially bonded cable circuits complying with the requirements of ENA ER C55/4 may require further tests

in addition to the over-sheath tests above.


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5.4 66kV and 132kV Cables

5.4.1 New and Existing Cables – 66kV and 132kV Oil and Gas Pressure Assisted Cables

It is essential before energisation to check the cable is continuous from end-to-end. This will ensure that the cable is laid as planned and that any route joints have been completed.

The cable shall withstand a dc test voltage of negative polarity applied between the conductor(s) and sheath with the sheath earthed.

Table 5-4 shows the minimum voltages to be used. No breakdown of the insulation shall occur.

All EHV and HV cable test results shall be recorded in accordance with Section 11.

Table 5-4 – Minimum Test Voltages for New and Existing Fluid and Gas Filled 66kV and 132kV Cables


dc Test Voltage for New Cable Systems (kV)

Minimum dc Test Voltage for Systems with old Cable (kV)

Duration (min)

Test Application

66 170 71 15

Test voltage applied to one phase with the other two phases connected

to earth/metallic screen 132 305 130

5.4.2 New and Existing Cables – 66kV and 132kV Cables Containing XLPE Insulated Cable

It is essential before energisation to check the cable is continuous from end to end. This will ensure that the cable is laid as planned and that any route joints have been completed. The cable shall withstand an ac test voltage applied between a conductor and sheath or all conductors with the sheath earthed. A Partial Discharge (PD) test shall be carried out during the all ac tests and the results recorded. The test will normally be provided by a series resonant or OWTS test set operating close to power frequency.

Table 5-5 shows the minimum voltages to be used. No breakdown of the insulation shall occur and the PD value for each phase shall not be more than 15% greater than either of the other two phase on the same circuit. If the cable system contains sections of existing fluid filled, gas filled or XLPE cable the test voltage should be reduced in line with Table 5-6.

All EHV and HV cable test results shall be recorded in accordance with Section 11.

Table 5-5 – Minimum Test Voltages for New 66kV and 132kV XLPE Cables


RMS ac Test Voltage for New Cable Systems (kV) – Phase to Earth

Frequency (Hz) Duration (min)

66 72 20 - 300 60

132 132


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Table 5-6 – Minimum Test Voltages for 66kV and 132kV Cable Containing Existing Sections of Cable


Existing cable less than 5 years old

Existing cable less than 20 years old

Existing cable more than 20 years old

RMS ac Test Voltage (kV)

Duration (min)


Duration (min)


Duration (min)

66 72 60

61 60

54 60

132 132 114 95

5.4.3 Cable Fault Location – 66kV and 132kV

It is permissible to apply higher dc voltages for fault location up to the maximum shown in Table 5-7.

Table 5-7 – Maximum Voltage Levels for Fault Location for 66kV and 132kV Cable Systems

Rated Line Voltage (kV) dc Test Voltage (kV) to Earth

66 50

132 50

5.4.4 Cable Over-sheath Tests – 66kV and 132kV Cables

The test voltages for over-sheath tests are given in Table 5-8. All cable over-sheath tests shall be carried out as specified in ECP 11-0007. These tests shall be applied under the following circumstances:

For all new cables (having an insulated sheath):

o After the cable drum has been off loaded from the delivery vehicle, visually inspected and checked; and before the cable is pulled in.

o After the cable has been installed (either direct buried or ducted). o After the complete circuit has been jointed and prior to energisation.

When returning an insulated sheath cable to service following diversion or repair.

Note: All drums should have been sheath tested in the factory before shipment and the onsite values should be

compared to these. If damage is found during the initial visual inspection, it should be photographed and the supplier shall be contacted, prior to the cable being sheath tested and installed.

Table 5-8 – Cable Over-sheath Test Voltages for Cables – 66kV and 132kV

System Nominal Voltage (kV)

Minimum dc Test Voltage (kV) Test Duration (min)

Maximum Leakage Current (mA)

Test Application

New Cables On Return to Service

66 10

Not Applicable 1 10

Between metallic sheath and earth

132 5

Note: Specially bonded cable circuits complying with the requirements of ENA ER C55/5 may require further tests

in addition to the over-sheath tests above.


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6 Switchgear Testing

6.1 Test Voltages

6.1.1 New switchgear

The test voltages to be used for new switchgear are given in Table 6-1. These test voltages shall apply to:

All extensible switchgear which incorporates site-made high voltage connections.

Any non-extensible switchgear where work has been carried out affecting the insulation.

Note: For clarification, removal and replacement of the SF6 gas does not require dielectric retesting of the system.

Where factory assembled and tested GIS panels are supplied, comprising circuit-breaker, disconnectors and earth switches, dielectric testing of individual panels is not required on-site.

If work on site requires dismantlement of any factory built and tested equipment, then an assessment of the re-testing required shall be made and agreed with UK Power Networks Asset Management.

For non-extensible switchgear at all voltages (including, for example, dead and live tank 132kV circuit-breakers) which has been factory tested, and on which no work has been carried out on the insulation, a test voltage of 5kV dc shall be applied for one minute.

6.1.2 Existing switchgear

The test voltages to be used for existing switchgear are given in Table 6-2. These test voltages shall apply to:

All switchgear where work has been done affecting the insulation (where the insulation has not been disturbed a 5kV megger test for 1 minute shall be carried out).

All switchgear which has been re-installed.

6.1.3 Application of Test Voltage

The test voltages shall be applied:

1. Between phases and phase to earth with the contacts closed:

Test voltage applied to

Earth applied to

OR

Test voltage applied to

Earth applied to

L1 L3 + L2 L1 and L2 L3

L2 L1 + L3 L2 and L3 L1

L3 L1 + L2


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2. Across the open contacts (unless assembled and dielectric tested in the factory):

Test voltage applied to Earth applied to

L1, L2 and L3 L1, L2 and L3 opposite contacts

If the equipment has been assembled and tested in the factory, a valid test certificate shall be provided with the equipment, demonstrating the method of testing and the results.

If surge diverters, neutral voltage displacement (NVD), capacitor bushings, etc. cannot be disconnected then the manufacturer’s advice should be obtained before proceeding.

Table 6-1 – Test Voltages for New Extensible Switchgear

Rated Line Voltage (kV) Switchgear Rated Voltage

ac Test Voltage (kV)

Test Duration (min)

Up to 11kV 12kV 22 (see note 1)

1

20/22 24kV 40 (see note 1)

33 36kV 56 (see note 1)

66 72.5kV 112 (see note 1)

132 145kV 220 (see note 1)

Table 6-2 – Test Voltages for Existing Switchgear

Rated Line Voltage (kV) Switchgear Rated

Voltage 3

ac Test Voltage (kV)

Test Duration (min)

Up to 6.6 7.2kV 10 (see note 2)

1

11 12kV other than above 16.5 (see note 2)

20/22 24kV other than above 33 (see note 2)

33 36kV 50 (see note 2)

66 (see note 3) 72.5kV 99 (see note 2)

132 (see note 3) 145kV 198 (see note 2)

Notes: 1. The ac test voltage for new extensible switchgear is 80% of factory test and should also include a 5kV IR result

both before and after the ac test. 2. The switchgear will withstand the full test voltage applied to new equipment but to reduce the stress for this

and subsequent tests the test voltage for existing switchgear has been reduced to 1.5 times the line voltage. 3. See alternative soak test for 66kV and 132kV GIS switchgear.


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6.2 Alternative Soak Test for 66kV and 132kV GIS Switchgear

An alternative regime for retesting 66kV and 132kV GIS switchgear, following an earlier full test, is to connect the switchgear to the network for a 24 hour period to soak test it rather than apply a voltage test.

This test has been approved because:

The difficulty, expense and risk of providing full test voltage immediately prior to energisation.

Connecting and disconnecting the test set to GIS equipment, involves work on the equipment; consequently the reconnection and re-gassing after removing the test set is not then tested.

This option is available to the SAP who will supervise the re-commissioning if:

The switchgear is GIS, requiring opening of gas compartments for connecting and disconnecting the test connections.

No external insulation has been disturbed in the parts being tested.

The protection is arranged such that in the event of a fault on the equipment being tested no loss of supplies to customers shall occur.

The system fault level is reduced to the lowest possible level and access to the plant under test is restricted.

6.3 Air Insulated Busbars and Disconnectors

Testing of air insulated busbars, air break isolators or post insulators, etc. is not required by this standard providing a visual inspection is made prior to energisation.


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7 Transformer Testing

The assembly of transformers, transport arrangements, quality controls during installation and sealing is such that high voltage insulation testing is generally unnecessary. Unless otherwise agreed with the manufacturer the only testing required for transformers (including pole-mounted) is insulation resistance testing using the test voltages given in Table 7-1. The insulation resistance shall be comparable with the original test documentation (if available). If, in order to test other equipment, it is necessary to apply a higher test voltage to the windings, then the voltages given in Table 7-2 should not be exceeded.

Table 7-1 – Test Voltages for Transformers

Test System Nominal Voltage (kV)

dc Test Voltage (kV)

Test Duration (min)

Test Application

Winding Insulation

Up to 6.6

1

1

Apply to each winding in turn with the other winding(s) earthed

11

22

33 1 – 2.5 (see note)

66 2.5

132

Core Insulation

All 1 1

Core insulation should be clear of earth with core earth link removed and connected to earth after core earth link replaced

Note: The test voltage specified in the manufacturers test documentation should be used.

Table 7-2 – Maximum Test Voltages for Transformers (for example where other equipment is connected)

System Nominal Voltage (kV) dc Test Voltage (kV) Test Duration (min)

6.6 6.6

1

11 11

22 22

33 33

66 66

66 (graded insulation) 30

132 (graded insulation) 50

Note: If a higher test voltage is to be considered, the manufacturer should be consulted prior to testing.


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8 Transformer Tails and Test Access

Where test access is available transformer tails shall always be tested. Where test access requires the dismantlement of apparatus and the SAP considers the risk to personnel of gaining the test access is higher than the risk of failure then the test may be omitted. This will usually apply at 11kV primary substations where the cable tails are within the UK Power Networks site and there is no reason to believe there has been any damage.

9 Overhead Line Testing

Insulation testing of overhead lines is not considered reasonably practicable. However, before commissioning, a visual inspection shall be made of new overhead lines and the modified parts of previously energised lines.

Also, before re-commissioning overhead lines that have been de-energised for an extended period of time, a risk assessment shall be made to decide if a visual inspection is required. This assessment shall take into account factors, such as the activity of third parties in the vicinity of the circuit and severe weather conditions.

10 Other Equipment

Other equipment that has been factory assembled, subjected to routine factory testing and for which a test certificate is available on site, and where no disturbance to the insulation has been made, shall be subjected to the following.

A visual inspection for damage or deformation before and after installation;

A 5kV megger test for 1 minute.

An example of other equipment is a 33kV through wall bushing.

11 Test Results

The results of the all tests shall be recorded as specified in ECP 11-0001 and ECP 11-0002.

All cable insulation test results shall be recorded on test form ECP 11-0006a unless the cable testing is part of substation commissioning when the results should be recorded on appropriate test form ECP 11-0501a (secondary) or ECP 11-0202 (grid and primary).


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12 References

12.1 UK Power Networks Standards

UK Power Networks Distribution Safety Rules

ECP 11-0001 Grid and Primary Installation Commissioning Requirements

ECP 11-0002 Secondary Commissioning Requirements

ECP 11-0006a EHV and HV Cable Insulation Test Form

ECP 11-0007 HV Polymeric Cable Sheath Testing Procedure

ECP 11-0202 HV Pressure Test Form

ECP 11-0501a Secondary Substation Commissioning Form

12.2 National and International Standards

ENA ER C55/4 Insulated Sheath Power Cable Systems

13 Dependent Documents

The documents below are dependent on the content of this document and may be affected by any changes.