TP_109

Uncontrolled when Printed

The National Grid Company plc

Transmission Procedure TP109 Numbering & Nomenclature of HV Apparatus

Issue 1 April 1999

Authorised by

..................................................... General Manager (on behalf of NGC Transmission)

NOT TO BE GIVEN TO EXTERNAL COMPANIES - Please refer external enquiries to Business Resources, Leatherhead, 216 3719


8 The National Grid Company plc 1999 No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise, without the written permission of the NGC obtained from the issuing location. The contents of The National Grid Company plc engineering documents are based on the needs of NGC and the conditions conditions under which it operates. It should not therefore be assumed that the specifications and requirements stated therein necessarily meet the particular circumstances and requirements of other organisations. No responsibility can therefore be accepted for any loss or damage sustained as a result of using or relying on the documents. Registered Office National Grid House Kirby Corner Road Coventry CV4 8JY Registered in England and Wales No. 2366977 Published by: The National Grid Company plc Kelvin Avenue Leatherhead Surrey KT22 7ST Administrative enquiries regarding this document should be directed to: ET Administration Team at Leatherhead, Telephone: 01372 383818 This Document has been prepared by the following people: Steve Pape (Author) Alan Gregory Lyndon Kilvington

System Manageme men nt Project Management Network Services



TP109 Issue 1 April 1999

CONTENTS 1

PURPOSE.............. PURPOSE................... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ......1 .1

2

DEFINITIONS..... DEFINITIONS.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ..........1 .....1

3

RESPON RESPONSIB SIBILI ILITIE TIES S ...... ......... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ..... ..... ....1 .1

4

PROCED PROCEDURE URE ...... ......... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ....2 .2

5

REFEREN REFERENCES.... CES....... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ..... ..... ...... ...3 3

6

RECORDS..... RECORDS.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... ......... ......... .......... ......3 .3

APPENDIX A.................................. A.......................................................... ................................................ ................................................. .......................................... ...............................4 ..............4




NGC Confidential

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NUMBERING AND NOMENCLATURE

1

PURPOSE

1.1

This procedure describes the allocation of Numbering and Nomenclature to High Voltage Equipment on The National Grid Company plc=s (NGC) Transmission System.

1.2

It implements Grid Code requirement Operating Code(OC) No. 11 "Numbering and Nomenclature of High Voltage Equipment at Certain Sites." In that :

(a)

NGC HV Equipment on Users' Sites; and

(b)

User HV Equipment on NGC Sites; shall have numbering and nomenclature in accordance with the system used by NGC.

1.3

To ensure, so far as possible, the safe and effective operation of the total Transmission System and to reduce the risk of human error faults by requiring, in certain circumstances, that the numbering and nomenclature of Users' HV Equipment shall be in accordance with the numbering system used by NGC.

1.4

The NGC system for numbering and nomenclature is derived from the ex-CEGB Document - Operation Memorandum No. 5. This Transmission Procedure has been updated to reflect the introduction of new types of equipment.

2

DEFINITIONS

2.1

OC11 applies to NGC and to Users, which OC11 defines as: Generators, Suppliers, Non-Embedded Customers and any other person with a User System directly connected to the NGC Transmission System to which Power Stations and/or Customers are connected.

2.2

User Site A site owned (or occupied pursuant to a lease, licence or other agreement) by a User in which there is a Connection Point. For the avoidance of doubt, where a site is owned by NGC but occupied by a User, the Site is a User Site.

2.3

NGC Site A site owned (or occupied pursuant to a lease, licence or other agreement) by NGC in which there is a Connection Point. For the avoidance of doubt, where a Site is owned by a User but occupied by NGC, the site is an NGC Site.

3

RESPONSIBILITIES

3.1

System Management are responsible for agreeing with other NGC Business Units the application of the principles of this procedure.

3.2

The NGC Business Unit which initiates the modification to the NGC HV system will be responsible for beginning the process of agreeing the numbering and nomenclature. The timing of this process should be sufficient to allow discussion and approval prior to excessive costs being incurred.

3.3

The NGC Business Unit which initiates modifications to overhead lines will be responsible for approaching Engineering and Technology who will allocate line route letters and circuit identification plates (CIP). If necessary the allocated line route letters and CIP will be agreed with Network Services.

4

PROCEDURE

NOT TO BE GIVEN TO EXTERNAL COMPANIES - Please refer Page 3 of 40 external enquiries to Business Resources, Leatherhead, 216 3719



4.1

The terms 'Disconnector' and 'Isolator' are synonymous but this document uses the preferred term 'Disconnector' throughout. The choice of which term to use at any particular location shall be made as follows:-

4.2

Existing and minor extensions to existing substations shall retain the predominant existing term. However, where any future extension forms a major part of the installation the term 'Disconnector' shall be used for all new equipment and the existing equipment nomenclature shall be changed to 'Disconnector'. All future substations should use the term 'Disconnector' throughout.

4.3

An overhead line route and its towers shall not be numbered or colour coded such that they could be readily confused with any other geographically close route or tower. The designation letters Q, I, J and O would not be considered appropriate for use in these circumstances.

4.4

NGC HV Equipment on Users' Sites (OC11.4.2)

(a)

NGC HV Equipment on Users' Sites will have numbering and nomenclature in accordance with the system used by NGC.

(b)

When NGC is to install its HV Equipment on a User's Site, NGC shall notify the relevant User of the numbering and nomenclature to be adopted for that HV Equipment at least eight months prior to proposed installation.

(c)

The notification will be made in writing to the relevant User and will consist of both a proposed Operation Diagram incorporating the proposed new NGC HV Equipment to be installed, its proposed numbering and nomenclature, and the date of its proposed installation.

(d)

The relevant User will respond in writing to NGC within one month of the receipt of the notification, confirming receipt and confirming either that any other HV Equipment of the relevant User on such Site does not have numbering and/or nomenclature which could be confused with that proposed by NGC, or, to the extent that it does, that relevant other numbering and/or nomenclature will be changed before installation of the NGC HV Equipment.

(e)

The relevant User will not install, or permit the installation of, any HV Equipment on such Site which has numbering and/or nomenclature which could be confused with NGC HV Equipment which is either already on that Site or which NGC has notified that User will be installed on that Site.

4.5

User HV Equipment on NGC Sites (OC11.4.3)

(a)

User HV Equipment on NGC Sites shall have numbering and nomenclature on the basis of that used by NGC.

(b)

When a User installs new HV equipment or replaces existing HV equipment on an NGC site and wishes to adopt new numbering and nomenclature the User shall notify NGC in writing of equipment details, numbering and nomenclature at least eight months prior to installation. This notification should be in Operation Diagram format and include the proposed date of utilisation.

(c)

NGC will respond in writing within one month on the acceptability of the proposed numbering and nomenclature. If it is not acceptable NGC will indicate suitable alternatives which the user shall adopt.

4.6

Changes (OC11.4.4) Where NGC in its reasonable opinion has decided that it needs to change the existing numbering or nomenclature of NGC HV Equipment on a User's Site or of User's HV Equipment on an NGC Site:

(a)

the provisions of paragraph OC11.4.2 shall apply to such change of numbering or nomenclature of NGC HV Equipment with any necessary amendments to those provisions to reflect that only a change is being made and;

(b)

in the case of a change in the numbering or nomenclature of User's HV Equipment on an NGC Site, NGC will notify the User of the numbering and/or nomenclature for that HV Equipment. This notification is to

NOT Page 4TO of 40 BE GIVEN TO EXTERNAL COMPANIES - Please refer external enquiries to Business Resources, Leatherhead, 216 3719



be in a form similar to that envisaged under OC11.4.2 and at least eight months prior to the change being needed. The User will respond in writing to NGC within one month of the receipt of the notification, confirming receipt. In either case the notification shall indicate the reason for the proposed change. 4.7

Availability of current system (OC11.4.5) User's will be provided upon request with details of NGC's current numbering and nom enclature system in order to assist them in planning the numbering and nomenclature for their HV Equipment on NGC Sites.

4.8

Labelling (OC11.4.6) When either NGC or a User installs HV Equipment which is the subject of OC11 either NGC or the User, as the case may be, shall be responsible for the provision and erection of clear and unambiguous labelling showing the numbering and nomenclature. Where either NGC or a User is required by OC11 to change the numbering and/or nomenclature of HV equipment, NGC or the User, as the case may be will be responsible for the erection of clear and unambiguous labelling showing the new numbering and nomenclature by the required date.

4.9

Changes to numbering system (OC11.4.7) NGC will not change its system of numbering and nomenclature embodied in this document, other than to reflect new or newly adopted HV Equipment technology.

4.10

It is not intended that any of the requirements of this document be applied retrospectively, except where the safety implications can justify the necessary expenditure.

5

REFERENCES

5.1

Operating Code (OC) 11

ANumbering and Nomenclature of High Voltage Equipment at Certain Sites@

5.2

TP 119

Transmission Operation Diagrams & Technical Data

6

RECORDS

6.1

Not applicable




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APPENDIX A Numbering and Nomenclature of HV Equipment (Update of CEGB Document Operation Memorandum No. 5 Numbering and Nomenclature of HV Apparatus on the CEGB Grid System issue 3, 6 June 1983) PHILOSOPHY To ensure, so far as possible, the safe and effective operation of the total Transmission System and to reduce the risk of human error faults by requiring, in certain circumstances, that the numbering and nomenclature of HV Equipment shall be in accordance with a standard numbering system.

A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 A16 A17 A18 A19 A20

NAMING OF STATIONS SEQUENCE NUMBERING OF EQUIPMENT IN SUBSTATIONS IDENTIFICATION OF CIRCUITS IDENTIFICATION OF BUSBARS IDENTIFICATION OF TRANSFORMERS IDENTIFICATION OF REACTORS, COMPENSATORS AND BOOSTERS IDENTIFICATION OF FREE STANDING VOLTAGE AND CURRENT TRANSFORMERS LABELLING 400 kV SWITCHGEAR 275 kV SWITCHGEAR 132 kV SWITCHGEAR SWITCHGEAR BELOW 132 kV (EXCLUDING METAL ENCLOSED) METAL ENCLOSED TYPE SWITCHGEAR BELOW 132 kV HV DC SWITCHGEAR NOMENCLATURE FOR SHORTING/DISCHARGE SWITCHES ASSOCIATED WITH STATIC CAPACITORS. COMPENSATORS AND FILTERS EARTHING SWITCHGEAR NEUTRAL EARTHING EQUIPMENT GAS ZONE NUMBERING SPECIAL LAYOUTS ABBREVIATIONS

DIAGRAMS 1-11 - EXAMPLE NUMBERING AND NOMENCLATURE DIAGRAMS FOR DIFFERING CONFIGURATIONS

A1

NAMING OF STATIONS

A1.1

Substations (Switching Stations or Transforming Stations)

A1.1.1

Substation names shall be nominated by Commercial and System Strategy, who will, where necessary, consult and agree the name to be adopted with the SM, Operational Services. ET Network Replacement will maintain a database of substation names and short codes for NGC and other Users.

A1.1.2

No substation shall be given the same name as that of any other NGC substation or User Site on the system unless it is located on the same site as an existing NGC substation or user site, or as allowed for in paragraph A1.1.4.

A1.1.3

No substation shall be given a name that could be readily confused with the name of any other substation or user site on the system.




A1.1.4 Where two or more substations are located geographically close together they may be named independently or alternatively given the same name followed by their respective voltages or by letters:eg

Cardiff East Cardiff West West Weybridge 275 kV West Weybridge 132 kV

A1.2

User Sites

A1.2.1

User site names shall be nominated by such user, who will consult on and agree the name to be adopted with NGC Commercial and System Strategy.

A1.2.2

Except in special circumstances, no user site shall be given the same name, or one that could readily be confused with, that of any other user site or substation on the system unless it is located on the same site as an existing user site.

A1.2.3

Where circumstances dictate that a user site needs to assume the name of an existing substation or user site or a name that could readily be confused with an existing substation or user site, NGC Commercial and System Strategy will consult and agree the necessary adjustment of names with the relevant Users.

A1.2.4

Where two or more user sites are located geographically close together they may be named independently or alternatively given the same name followed by a letter:eg

Dungeness 'A' Dungeness 'B'

A2

SEQUENCE NUMBERING OF EQUIPMENT IN SUBSTATIONS

A2.1

Further to the requirements of section A5.6 for all transformers to be uniquely numbered and section 6 for reactors, compensators and boosters to be uniquely numbered, the following will apply:

A2.1.1

Where the above installations are associated with an even numbered busbar section, then an even numbered sequence shall be used and vise versa.

A2.1.2

Where the above installation is connected to the system via a static compensator transformer, then the circuit numbering will follow the sequence that is used for other transformer circuits.

A2.1.3

Where the next number in sequence could lead to confusion or ambiguity with adjacent equipment, the following number in sequence should be used.

A2.2

Sequence numbering which could lead to ambiguity at substations of different voltage on the same site should be avoided.

A3

IDENTIFICATION OF CIRCUITS

A3.1

The identification of circuits connecting substations at different named sites shall be as follows:-

A3.1.1

A circuit connecting two substations shall be designated by the names of the substations concerned in alphabetical order of sites. eg

Cottam - Grendon




A3.1.2 A circuit connecting three or more substations shall be designated by the names of all the substations concerned in alphabetical order of sites, tee points excepted. eg

A3.1.3

Aberthaw-Upper Boat-Cilfynydd Halewood-BOC Woodend-Widnes-Rainhill

Parallel circuits between the same substations shall be designated in accordance with paragraphs A3.1.1 or A3.1.2 above and shall be numbered uniquely. eg

Grendon-Sundon 1 Grendon-Sundon 2 East Claydon-Amersham Main-Iver 1 East Claydon-Amersham Main-Iver 2

A3.2

The identification of circuits connecting, at the same voltage, substations at the same named site shall be as follows:-

A3.2.1

A circuit connecting two substations shall be designated by the names of the two substations concerned and called an Interconnector.

A3.2.2

Parallel circuits between the same substations shall be identified in accordance with paragraph A3.2.1 above and shall be numbered uniquely.

A4

IDENTIFICATION OF BUSBARS

A4.1

The numbering and nomenclature of busbars other than those associated with power station auxiliaries shall be as follows:-

A4.1.1

Nominal busbar voltage (400 kV, 275 kV, 132 kV, etc).

A4.1.2

Busbar designation (Main Busbar, Reserve Busbar, Mesh Corner, etc).

A4.1.3

Busbar section number (1, 2, 3, etc). eg

275 kV Main Busbar 1

A4.1.4

Sections of busbars of the same nominal voltage and busbar designation shall be numbered consecutively from one end of the substation to the other. Main and reserve busbars shall have corresponding numbering.

A4.1.5

In the case of substations where one section of one busbar is common to two sections of an associated busbar, the former shall bear the numbers of both corresponding sections of the latter. eg

A4.1.6

The busbar section number shall be omitted in those cases where the busbar is a single busbar having no sectioning facilities. eg

A4.1.7

400 kV Main Busbar 1 400 kV Main Busbar 2 400 kV Reserve Busbar 2

275 kV Main Busbar

In the case of a mesh type substation the corners of the mesh shall be numbered consecutively in an anti-clockwise direction when viewed from above.




A4.2

The numbering and nomenclature of the principal busbars associated with power station auxiliaries shall be as follows:-

A4.2.1

Nominal busbar voltage (11 kV, 6.6 kV, 3.3 kV etc).

A4.2.2

Busbar designation (Station Board, Unit Board).

A4.2.3

Busbar number (1, 2, 3, etc). This number shall be the number of the associated transformer or generator. eg

A4.2.4

11 kV Unit Board 1

In the case of busbars with sectioning facilities the word ASECTION@followed by a consecutive number or letter shall be added. eg

11 kV Unit Board 1 Section 1

A5

IDENTIFICATION OF TRANSFORMERS

A5.1

The identification of all transformers (except earthing transformers) shall include a prefix indicating the ratio of the nominal voltages eg 400/132 kV.

A5.2

The numbering and nomenclature of transformers connected to the NGC System, other than those directly associated with converting, compensating equipment or generators and their auxiliaries and with due regard to the development of the substation, shall be as follows:-

A5.2.1

A transformer with a nominal primary voltage of 400 kV or 275 kV which connects with a lower voltage system, shall be designated a SUPERGRID TRANSFORMER. All such Supergrid Transformers shall be numbered uniquely in relation to each other and to any other transformers, excluding generator transformers, with 400 kV or 275 kV windings at a particular named site and where appropriate, the provisions of paragraphs A5.3, A5.4 and A5.5 shall apply.

A5.2.2

A transformer with a nominal primary voltage of 132 kV which connects with a lower voltage system shall be designated a GRID TRANSFORMER. All such transformers shall be numbered uniquely in relation to each other and to any other transformers, excluding generator transformers, with 132 kV high voltage windings at a particular named site and where appropriate, the provisions of paragraphs A5.3, A5.4 and A5.5 shall apply. This nomenclature shall apply at named sites where 66 kV is the primary voltage and there is no transformation from 132 kV.

A5.2.3

A transformer with the next highest primary voltage below that of a Grid Transformer shall be designated a INTERBUS TRANSFORMER and all such transformers at a particular named site shall be numbered uniquely.

A5.2.4

Other transformers at a particular named site shall be designated by reference to the ratio of the nominal voltages and shall be numbered uniquely. eg

11/6.6 kV Transformer 1

A5.3

A transformer connected to ac/dc converting equipment and provided for the transmission of power shall be designated CONVERTER TRANSFORMER. All such transformers shall be numbered uniquely at a particular named site and where appropriate, the provisions of paragraphs A5.2.1 or A5.2.2 shall apply.

A5.4

A transformer provided at a user site to supply the station board and having a nominal high voltage of 400 kV, 275 kV or 132 kV shall be designated STATION TRANSFORMER. All such transformers shall be numbered uniquely at a particular named site and where appropriate, the provisions of paragraphs A5.2.1 or A5.2.2 shall apply.

NOT TO Page 10 of 40BE GIVEN TO EXTERNAL COMPANIES - Please refer external enquiries to Business Resources, Leatherhead, 216 3719



A5.5

A transformer provided solely for the purpose of connecting an item of compensating equipment, and not for the transmission of power, shall be designated COMPENSATOR TRANSFORMER. All such transformers shall be numbered uniquely at a particular named site.

A5.6

All transformers covered by the provisions of paragraphs A5.2, A5.3, A5.4 and A5.5 and being of the same nominal high voltage shall be numbered uniquely at a particular named site. eg

At a 400 kV site:400/275 kV Supergrid Transformer 1 400/11 kV Station Transformer 2 400/275 kV Supergrid Transformer 3 400/132 kV Converter Transformer 4 400/132 kV Supergrid Transformer 5 400/11 kV Station Transformer 6 400/132 kV Supergrid Transformer 7

A5.7

The numbering and nomenclature of transformers directly associated with users equipment shall be as follows:-

A5.7.1

A transformer connected to a generator and provided for the transmission of the generator output to the main system shall be designated GENERATOR TRANSFORMER and shall be numbered the same as the associated generator.

A5.8

A transformer provided to supply a power station unit board and connected to a generator shall be designated UNIT TRANSFORMER and shall be numbered the same as the associated generator. Where more than one UNIT TRANSFORMER is provided the individual transformers shall be numbered as the associated generator and be identified by the addition of a consecutive letter as a suffix.

A5.9

Where two or more transformers in a substation or power station are banked on to a circuit breaker on either the high voltage or the low voltage side the individual transformers shall have the same number and be identified by the addition of a consecutive letter as a suffix. eg

275/132 kV Supergrid Transformer 1A 275/132 kV Supergrid Transformer 1B

A5.10

The numbering and nomenclature of a transformer directly connected to another transformer shall be as follows:-

A5.10.1

A transformer providing a system neutral connection and not supplying auxiliaries shall bear the designation and number of the transformer to which it is connected followed by the voltage of the winding to which the transformer is connected and the words EARTHING TRANSFORMER. eg

A5.10.2

A transformer supplying local auxiliaries and not providing a system neutral connection shall bear the designation and number of the transformer to which it is connected, and the voltage ratio of the auxiliary transformer, followed by the words AUXILIARY TRANSFORMER. eg

A5.10.3

Supergrid Transformer 4 13 kV/415V Auxiliary Transformer.

A transformer providing a system neutral connection and supplying auxiliaries shall bear the designation and number of the transformer to which it is connected, followed by the voltage of the winding to which the transformer is connected and the words EARTHING AND AUXILIARY TRANSFORMER, with the voltage of the equipment supplied preceding the word AUXILIARY. eg

A5.10.4

Supergrid Transformer 3 13 kV Earthing Transformer.

Supergrid Transformer 1 13 kV Earthing and 415V Auxiliary transformer.

The overriding concern is that equipment should be identified within isolatable zones. (See diagram 10.)




A6

IDENTIFICATION OF REACTORS, COMPENSATORS AND BOOSTERS

A6.1

At nuclear power station sites the term 'INDUCTOR' shall be used instead of 'REACTOR' to describe an electrical reactor, in order to avoid any possible confusion with nuclear reactors.

A6.1.1

The preferred name for capacitive Compensation Circuits will be Mechanically Switched Capacitors. These may be made up of one or more individually switched static capacitors.

A6.2

The numbering and nomenclature of reactors/inductors, capacitors, compensators and boosters shall be as follows:-

A6.2.1

Nominal Voltage eg 400 kV, 66 kV

A6.2.2

Description eg series reactor, static capacitor. In all cases the word reactor, capacitor or booster shall be qualified by an appropriate adjective.

A6.2.3

Number

(a)

In the case of equipment connected to a mesh type substation this number shall be the number of the associated mesh corner.

(b)

In the case of equipment connected to a transformer tertiary winding this number shall be the number of the associated transformer except for equipment identified under section A6.1.3.3. If the associated transformer is a banked transformer the appropriate letter shall also be included.

(c)

In the case of a relocatable SVC (RSVC) this will be a unique name letter (A,B...Z, AA, AB, ... as appropriate). A central register of RSVC identifications will be maintained to which reference should be made when determining nomenclature for any new RSVC.

(d)

Relocatable SVC elements situated within a supergrid transformer isolation zone shall have dual naming eg

Supergrid Transformer 1 / RSVC A 13 kV Earthing and 415V Auxiliary transformer.

(e)

In other cases this number shall be a sequence number.

A6.2.4

Where two items qualify for the same number and nomenclature, the word WINDING shall be added to reactor nomenclature followed by an identification letter. Similarly the work BANK shall be added to capacitor nomenclature followed by an identification letter. eg

13 kV Shunt Reactor 4B Winding A 13 kV Static Capacitor 1 Bank A

A6.3

The information given above for shunt reactors is illustrated in Diagram 8.

A7

IDENTIFICATION OF FREE STANDING VOLTAGE AND CURRENT TRANSFORMERS

A7.1

The nomenclature of free standing voltage and current transformers shall be as follows.

A7.2

The designation and number of the associated equipment or circuit to which the voltage or current transformer is directly connected.

A7.3

The nominal voltage.

A7.4

The words VOLTAGE TRANSFORMER or CURRENT TRANSFORMER as appropriate.


Uncontrolled when Printed A7.5 used.


Where two items qualify for the same nomenclature, reference to adjacent plant/equipment may be

eg

Supergrid Transformer 2 400 kV Voltage Transformer. X120 400 kV Current Transformer (X124 side).

A8

LABELLING

A8.1

Switchgear Labelling

A8.1.1

All switchgear should carry the labelling identified in this procedure along with the circuit designation eg

for 400/132 kV SGT3 HV circuit breaker: SGT3 X310

A8.1.2

Where the operation of equipment requires action at phase level, each phase shall be clearly identified.

A8.2

Panel Labelling

A8.2.1

Circuits

(a)

Switchgear control, protection equipment and metering panels associated with a circuit shall be labelled in accordance with Section 3, except that the name of the substation at which the panel is located shall be omitted. For multi-ended circuits the order of naming should be in order of proximity. eg

At Walpole on the Walpole-Norwich 1 and 2 circuits labels would read: Norwich 1, Norwich 2. At Kingsnorth on the Kingsnorth-Tilbury-Rayleigh circuit, labels would read: Tilbury-Rayleigh

(b)

Each control handle or other control facility shall have a label adjacent to it designating the equipment controlled. eg

L45 (see sections 9-17).

(c)

Where a circuit is terminated with a transformer circuit breaker, labelling shall be in accordance with the provisions of paragraph A8.2.2.4.

A8.2.2

Transformer Circuits

(a)

Switchgear control, protection equipment and metering panels associated with a transformer circuit shall be labelled in accordance with Section 5. Where the use of the full identification is impractical the voltage ratio prefix may be omitted. eg

(b)


(c)

Supergrid Transformer 6.

180 (see sections 9-17).

HV and LV relay panel labelling for a typical 400/132 kV Supergrid Transformer shall be:Supergrid Transformer 1 400 kV Relay Panel Supergrid Transformer 1 132 kV Relay Panel

(d)

At substations where a transformer circuit breaker acts as the termination of a line circuit the HV and




LV relay panels shall include the circuit designation in accordance with paragraph 14.1.1. eg

At Alverdiscott on the Indian Queens -Alverdiscott - Taunton 1 circuit, labels would read: Supergrid Transformer 1 (Indian Queens - Taunton 1) 132 kV relay panel

A8.2.3

Other Equipment

(a)

Switchgear control, protection equipment and metering panels associated with other equipment shall be labelled in accordance with the nomenclature of the equipment. eg

(b)

Separate labelling of protection relays, etc. shall be provided where appropriate. eg

(c)

13 kV Shunt Reactor 4A 13 kV Static Capacitor 3

Winding A Bank B


4KO (see sections 9-17)

A9

400 kV SWITCHGEAR

A9.1

The nomenclature of 400 kV switchgear shall be the designation and number of the associated equipment, followed by a description of the function of the particular item of switchgear.

A9.2

The numbering of 400 kV switchgear shall be three or four numbers preceded by the letter 'X'.

A9.2.1

The first number (or two numbers in a sequence of four) shall be used to denote the sequence of switchgear groups in any one class in a substation.

(a)

In the case of a generator circuit the first number shall be the generator number.

(b)

In the case of a transformer circuit connecting busbars at the same named site, the first number shall be the number of the transformer or transformer bank.

(c)

The switchgear groups of line circuits shall be numbered from an end of the substation that is not designed to be extended. If a substation is designed to be extended in both directions the switchgear groups on one side of the substation shall be given odd numbers and those on the other shall be given even numbers, commencing from a sectioning or other suitable point.

(d)

A transformer circuit connecting busbars at different named sites shall be considered as a transformer circuit only at the substation where that transformer is located, with the exception that line numbering be applied in the case of an earthing switch on the line side of the circuit disconnector. Other terminations of the circuit shall be considered as line circuits.

(e)

In the case of a bus-coupler; the number 1 bus-coupler circuit breaker shall connect main and reserve busbars in section 1, number 2 bus-coupler circuit breaker shall connect main and reserve busbars in section 2, etc.

(f)

In the case of a bus-section; number 1 bus-section circuit breaker shall connect busbar sections 1 and 2, number 2 bus-section circuit breaker shall connect busbar sections 2 and 3, etc.

(g)

In the case of a mesh type substation, equipment numbering shall be determined by the corner number to which it is connected (Bus Section 1 shall be between mesh corners 1 and 2, etc.).

(h)

Where the same switchgear is used to control a line and a local transformer, then line numbering shall




be applied to the switchgear. A9.2.2

The second number shall be used to denote the class of switchgear group as given in table 1 below:-

TABLE 1 *0* *1* *2* -

*3* *4* *5* *6* *7* *8* *9* -

Line Transformer high voltage side Main Bus Section Mesh Busbar Interconnector (within a substation) Bus Coupler Quad Booster or Series Reactor Static Shunt Compensator Reserve Bus Section (Spare) Transformer low voltage side Generator Synchronous Compensator

(a)

Switchgear inserted in lines associated with teed circuits at a named site, other than the high voltage terminations of the circuits, shall be considered as main busbar section switchgear.

(b)

Switchgear provided specifically for the purpose of switching a transformer from one circuit to another shall be considered as main busbar section switchgear.

(c)

The third number shall be used to denote the function of the particular item of switchgear in the group as given in table 2 below:-

TABLE 2 **0 -

**1 **2 **3 **4 **5 -

**6 **7 **8 **9 -

Circuit breaker (excluding lines) Circuit breaker (2nd choice lines) Circuit breaker associated with main busbar on double switched equipment Switch disconnecter (lines) Earthing switch By-pass disconnecter Circuit disconnecter Main busbar disconnecter Circuit breaker (lines) Circuit breaker (2nd choice excluding lines) Circuit breaker associated with reserve busbar on double switched equipment Switch disconnecter (excluding lines) Reserve busbar disconnecter Mesh opening corner disconnecter Circuit breaker disconnecter, busbar side Main busbar disconnecter (2nd choice) Reactor tie busbar disconnecter Reserve busbar disconnecter (2nd choice)

A9.2.4

Where more than one item in a group qualifies for a particular number the number shall be suffixed by consecutive letters, commencing from the circuit termination inwards to the busbar selector disconnectors.

A9.2.5

In the case of banked circuits the numbers shall be suffixed by the identification letter of the appropriate circuit for those items of equipment which are not common to all the circuits of the bank. In general,




a suffix shall not be used for items common to all circuits of the bank except in those instances where the number is repeated, when an appropriate letter suffix shall be added. A9.3

The implementation of both the 400 kV nomenclature and numbering is illustrated in table 5 at the end of this document and in diagrams 1-4.

A10

275 kV SWITCHGEAR

A10.1

The nomenclature of 275 kV switchgear shall be the designation and number of the associated equipment followed by a description of the particular item of switchgear.

A10.2

The numbering of 275 kV switchgear shall be made up as follows:-

A10.2.1

A letter shall precede two or three numbers and shall be used to denote the class of switchgear group as given in the Table 3 below:-

TABLE 3 L** H** S** -

W** R** K** P** Z** T** M** -

Line Transformer high voltage side Main Bus Section Mesh Busbar Interconnector (within a substation) Bus Coupler Quad Booster or Series Reactor Static Shunt Compensator Reserve Bus Section (Spare) Transformer low voltage side Generator Synchronous Compensator

A10.2.2

The first number (or two numbers in a sequence of three) shall be used to denote the sequence of switchgear groups in any one class on a named site. The number shall be derived in accordance with section A9.2.1

A10.2.3

The second number shall be used to denote the function of the particular item of switchgear in the group as given in Table 2. (Section A9.2.3).

A10.2.4

The provisions of paragraphs A9.2.2.1, A9.2.2.2, A9.2.4 and A9.2.5 shall apply.

A11

132 kV SWITCHGEAR

A11.1

The nomenclature of 132 kV switchgear shall be the designation and number of the associated equipment followed by the function of the particular item of switchgear.




A11.2

The numbering of 132 kV switchgear shall be in accordance with section A9.2 (numbering of 400 kV switchgear) excluding the prefix 'X', except for 11.3 below.

A11.3

In the case of banked circuits the numbers shall be suffixed by the identification letter of the appropriate circuit for those items of equipment which are not common to all the circuits of the bank. If a number of items qualify for the same number and letter sequence, a further number suffix shall be used as in section A16.1.2

A12

SWITCHGEAR BELOW 132 kV (EXCLUDING METAL ENCLOSED)

A12.1

The nomenclature of switchgear at nominal voltages lower than 132 kV shall be the designation and number of the associated equipment followed by a description of the function of the particular item of switchgear.

A12.2

The numbering of switchgear at nominal voltages lower than 132 kV, other than those associated with equipment connected to Supergrid or Grid Transformer tertiary windings, shall be made up as follows:-

A12.2.1

A letter prefixed and suffixed by a number.

A12.2.2

The number prefixing the letter shall be used to denote the sequence of switchgear groups in any one class in a substation.

(a)

In the case of a generator circuit, the number shall be the generator number.

(b)

In the case of a transformer circuit connecting busbars at the same named site, the number shall be the number of the transformer or transformer bank.

(c)

The numbering of the circuit breaker on the low voltage side of a Supergrid Transformer shall be SUPERGRID followed by the number and letter, if any, of the transformer. eg

(d)

Supergrid 1A

The numbering of the circuit breaker on the low voltage side of a Grid Transformer shall be GRID followed by the number and letter, if any, of the transformer. eg

GRID 1A

(e)

In the case of the transformer having two or more low voltage circuit breakers, these shall be identified uniquely in line with paragraph A13.1.4

(f)

In all other cases the number given shall be derived in accordance with paragraphs A9.2.1.3, A9.2.1.4, A9.2.1.5, A9.2.1.6, A9.2.1.7 and A9.2.1.8.

A12.2.3

The letter shall be used to denote the class of switchgear group as given in Table 3 (Section A10.2.1.1) with the addition given below.

(a)

A - Certain Auxiliary Equipment eg

- Grid Transformer 1 LV Voltage Transformer Disconnecter - 1A3

(b)

In the case of earthing switchgear solely associated with a transformer tertiary winding, the letter used shall indicate this connection, ie. the letter 'T' shall be used. (See diagram 8).

A12.2.4

The number suffixing the letter shall be used to denote the function of the switchgear in the groups as given in Table 2 (Section 9.2.3).




A12.2.5

Where more than one item qualifies for a particular number the provision of paragraphs A9.2.4 and A9.2.5 shall apply.

A12.3

The numbering of switchgear associated with equipment connected to Supergrid tertiary windings shall be made up as follows:-

A12.3.1

The number, and letter where appropriate, of the associated Supergrid Transformer. Except in the case of a relocatable SVC, see section A6.1.3.3

A12.3.2

A letter to denote the class of switchgear group (Sections A10.2 and A12.2.3). eg

K for a static shunt compensator M for a synchronous compensator

A12.3.3

A number to denote the function of the switchgear in the group as given in Table 2 (Section A9.2.3).

A12.3.4

Where more than one item in a group qualifies for a particular number, the number shall be suffixed by unique letters. eg

Shunt Reactor associated with 400/132 kV Winding A circuit breaker - 1KOA Winding B circuit breaker - 1KOB Synchronous compensator associated with 400/275 kV Supergrid Transformer 2B:Main Circuit breaker- 2BMO1 Starting Circuit breaker- 2BMO2 Running Circuit breaker- 2BMO3

A12.3.5

The information given above for shunt reactors is illustrated in Diagram 8.

A12.4

A comprehensive summary of the nomenclature and numbering of "Switchgear below 132 kV" other than LV Metal Enclosed is shown in tabular form in table 5 at the end of this document, whilst the implementation is illustrated in Diagram 1.

A13

METAL ENCLOSED TYPE SWITCHGEAR BELOW 132 kV

A13.1

The numbering and nomenclature of metal enclosed type switchgear associated with transformers shall be as follows:-

A13.1.1

Switchgear on the low voltage side of a Supergrid Transformer shall be named SUPERGRID followed by the number and letter, if any, of the transformer. eg

A13.1.2

Switchgear on the high voltage side of a grid Transformer shall be named GRID T followed by the number and letter, if any, of the transformer and the nominal voltage of the switchgear. eg

A13.1.3

SUPERGRID 1A.

GRID T1A 66 kV

Switchgear on the low voltage side of a Grid Transformer shall be named GRID followed by the number and letter, if any, of the transformer. eg

GRID 1B




A13.1.4

In the case of a transformer having two or more low voltage circuit breakers, these shall be identified as follows:-

(a)

In the case of a transformer having a number only, by the addition of consecutive letters. eg

Switchgear associated with Grid transformer 1:GRID 1A GRID 1B

(b)

In the case of a transformer having a number and letter, by the addition of consecutive numbers or other suitable qualification. eg

Switchgear associated with Grid Transformer 1B:GRID 1B1 GRID 1B1

A13.1.5

11 kV Station Transformer 2A

Switchgear associated with a Unit Transformer shall be named UNIT TRANSFORMER followed by the number and letter, if any, of the transformer and prefixed by the voltage. eg

A13.2

T1 11 kV T1 6.6 kV

Switchgear associated with a Station Transformer shall be named STATION TRANSFORMER followed by the number and letter, if any, of the transformer and prefixed by the voltage. eg

A13.1.8

INTERBUS 1 33 kV INTERBUS 1 11 kV

Switchgear associated with other Transformers excluding power station auxiliaries, shall be designated 'T' followed by the number and letter, if any, of the transformer and the nominal voltage of the switchgear. eg

A13.1.7

GRID 1B NORTH GRID 1B SOUTH

Switchgear associated with an Interbus Transformer shall be named INTERBUS followed by the number and letter, if any, of the transformer and the nominal voltage of the switchgear. eg

A13.1.6

or or

11 kV Unit Transformer 4

Switchgear associated with feeder circuits, excluding power station auxiliaries, shall be named by reference to all the terminations of the circuit excepting the location of the switchgear, including in the case of parallel circuits, the appropriate number. eg

At West Ham: Barking - East Ham 3

A13.3

The numbering and nomenclature of Busbar Section, Busbar Coupler, Busbar Interconnector and Busbar Reactor Switchgear, excluding power station auxiliaries, shall be as follows:-

A13.3.1

Switchgear provided for coupling Front and Rear busbars shall be named BUS COUPLER preceded by the nominal busbar voltage followed by the section number(s). eg

11 kV Bus Coupler 3




A13.3.2

Switchgear provided for sectioning Front or Rear busbars shall be named BUS SECTION preceded by the nominal busbar voltage and identification and followed by the adjacent section numbers. eg

A13.3.3

Switchgear provided for connecting remote sections of a busbar shall be named INTERCONNECTOR preceded by the nominal voltage and followed first by the busbar number(s) adjacent to the switchgear and then by the busbar number(s) at the remote end of the circuit. eg

A13.3.4

33 kV Reactor Interconnector 4/1

Switchgear associated with generator circuits shall be named GENERATOR followed by the number of the generator. eg

A13.5

66 kV Interconnector 4/1

Switchgear associated with a reactor circuit connecting sections of busbars shall be named REACTOR INTERCONNECTOR, SECTION REACTOR, or TIE BAR REACTOR, preceded by the nominal busbar voltage and followed by the busbar number(s) adjacent to the switchgear and then by the busbar number(s) at the remote end of the circuit. eg

A13.4

33 kV Front Bus Section 2

Generator 1

Metal Enclosed Type Switchgear (Shuttered) The shutters covering the contacts when the switchgear is withdrawn shall comply with the following:-

A13.5.1

Shutters covering contacts directly connected to busbars shall be coloured red and bear the identification of the busbar in white lettering. eg

33 kV FRONT BUSBAR 1

All other shutters shall be coloured yellow. A13.5.2

For incoming feeder contacts the yellow shutters shall bear in red lettering the identification of the circuit.

A13.5.3

When more than one set of shutters associated with a particular circuit breaker are coloured yellow they shall bear the designation of the equipment associated with the contacts which they cover.

A13.6

The implementation of the nomenclature given above under the heading "Metal Enclosed Type Switchgear", is illustrated in Diagram 6.

A14

HV DC SWITCHGEAR

A14.1

The nomenclature of DC switchgear shall be the designation and number of the associated equipment followed by the function of the particular item of switchgear.

A14.2

The numbering of DC switchgear shall be in accordance with section A9.2 (numbering of 400 kV switchgear) replacing the prefix 'X' by the letter 'D'.




A15

NOMENCLATURE FOR SHORTING/DISCHARGE SWITCHES ASSOCIATED WITH STATIC CAPACITORS, COMPENSATORS AND FILTERS.

A15.1

In general, switchgear numbering on static capacitor, compensator and filter circuits follows the requirements detailed in respect of nomenclature and also in the numbering of circuit breakers, disconnectors and earth switches. The numbering rules for shorting/discharge switches are as follows:

A15.2

Where switchgear used for shorting/discharge functions as a fully rated earth switch or maintenance earth on all phases at all points of application then it should be numbered as an earth switch or maintenance earth as appropriate. In all other cases the following numbering shall be applied:

A15.2.1

The first part shall be a number or letter(in the case of RSVC) to denote the circuit nomenclature.

A15.2.2

The second part shall be a letter to denote the type of circuit, i.e "C".

A15.2.3

The third part shall be the circuit sub-division reference as used on a banked circuit where appropriate.

A15.2.4

The fourth part shall be used, where necessary, for the numbering sequence for switchgear which would otherwise bear the same number. eg

For Static Capacitor 3 3C1, 3C2 3CA1, 3CA2 for Bank A

A15.3

The implementation of the information given above is illustrated in Diagrams 9 and 10.

A16

EARTHING SWITCHGEAR

A16.1

The numbering of perm anent earthing switches should, as far as possible, be in accordance with the preceding directives in sections A9-A15.

A16.1.1

Where more than one earthing switch qualifies for a particular number, then the number shall be suffixed by unique letters, and the provision of paragraphs A9.2.4 and A9.2.5 shall apply. In the case of busbar earthing switches such numbering should run from the end of the substation that is not designed to be extended or if a substation is to be extended in both directions, starting from some central or bussectioning point.

A16.1.2

Where two or more earthing switches are associated with a banked circuit which is already identified by use of a letter suffix, the earthing switches shall be furthered identified by use of an additional number suffix. eg

For circuit associated with 400 kV capacitor bank 1A earthing switches shall be X151A1, X151A2

A16.1.3

Where earthing switches are installed, which cannot be numbered in accordance with the directives in section A16.1.1 or A16.1.2 they shall be designated 'E' followed by a number. At a particular named site no number shall be duplicated.

A16.2

Where equipment is used which can perform the duties of both a disconnecter and earth switch then the earth part should be identified as the disconnecter followed by >ED=. eg

earthing device associated with IT4 IT4ED.

A16.3

Where fixed maintenance earthing equipment (i.e. earthing equipment applied phase by phase) is installed, it shall be designated 'F' followed by a number. At a particular named site no number shall be duplicated.

A16.4

Where a FAULT THROWER is fitted for the protection of a transformer, the nomenclature shall be as follows:-




A16.4.1

The designation and number of the associated transformer.

A16.4.2

The words FAULT THROWER. eg

A16.4.3

Grid Transformer 1 Fault Thrower

The identifying number shall consist of the prefix FT followed by the identification number of the transformer. eg

FT2A for Grid Transformer 2A

A17

NEUTRAL EARTHING

A17.1

The nomenclature of neutral earthing switchgear shall be the designation and number of the associated equipment followed by the words NEUTRAL EARTHING SWITCH.

A17.2

The numbering of neutral earthing switchgear, except in the case of common neutral earthing switchgear, shall be the letter 'N' followed by a sequence number.

A17.3

The numbering of common neutral earthing switchgear shall be as follows:-

A17.3.1

The first part shall be a letter to denote the type of circuit with which the switchgear is associated as given below:M -Generator T -Transformer P -Petersen Coil S -Section R -Neutral Resistor, Neutral Reactor or Neutral Earthing Point

A17.3.2

The second part shall be the number of the circuit.

A17.3.3

The third part shall be the letter N to denote the neutral earthing function.

A17.3.4

The fourth part shall be a sequence number, zero being reserved for neutral circuit breakers.

A17.4

The nomenclature of neutral earthing resistors shall be the designation and number of its associated equipment followed by the words NEUTRAL EARTHING RESISTOR. eg

Sync Comp 5 Neutral Earthing Resistor

A17.4.1

Where the neutral earthing resistor is common to more than one item of equipment it shall be designated COMMON NEUTRAL EARTHING RESISTOR followed where appropriate by a unique sequence number.

A17.5

The implementation of the information given above under the heading "Neutral Earthing Switchgear" is illustrated in Diagram 7 for certain arrangements.

A18

GAS ZONE NUMBERING

A18.1

Gas zone numbering associated with sulphur hexafluoride insulated Metal Enclosed switchgear will be numbered to associate with the relevant circuit following the switchgear numbering principles described above.

A18.2

Due to the diverse manufacturing types, specific numbering will be agreed on an individual substation basis after consultation with Operational Services, System Management.




A19

SPECIAL LAYOUTS

A19.1

Where, due to special layouts, direct application of this Procedure is impracticable, the numbering and nomenclature in line with the general principles embodied in the text shall be approved as follows:-

(a)

by SM Operational Services, (for equipment owned and/or controlled by NGC).

(b)

by SM Operational Services and the User Company Representative, (in the case of equipment not under the direct operational control of the NGC).

A19.2

When extensions to substations, not envisaged at the design stage, are undertaken, special care should be taken. Switchgear numbering on particular items of apparatus should not be swapped to tie in with new sequences if it is thought that greater confusion could result.




A20

ABBREVIATIONS

A20.1

To achieve a level of consistency in differing areas from alarm database management to acceptable labelling sizes the following can be used as abbreviations for the various plant items. Where the use of abbreviations could cause confusion eg safety related documents, their use should be limited.

TABLE 4 Plant Item

Abbreviation

Auxiliary and Earthing Transformer

AUX / E Tx

Auxiliary Transformer

AUX Tx

Bus Coupler

BC

Bus Section

BS

Cable Sealing End

CSE

Circuit Breaker

CB

Combined VT / CT Unit

VT/CT

Compensator Transformer

COMP T

Current Transformer

CT

Disconnector

DISC

Earth Switch

ESW

Earthing Transformer

E Tx

Generator

GEN

Generator Transformer

GEN T

Inductor

IND

Isolator

ISOL

(Liquid) Neutral Earthing Resistor

(L)NER

Main Busbar

MBB

Mechanically Switched Capacitor

MSC

Overhead Line

OHL

Quadrature Booster

QB

Reactor

RCT

Relocatable Static Var Compensator

RSVC

Reserve busbar

RBB

Static Capacitor

CAP

Static Var Compensator

SVC

Station Transformer

STN T




Super Gird Transformer

SGT

Switch Disconnector

SW DISC

Synchronous Compensator

SYNC COMP

Thyristor Switched Capacitor

TSC

Thyristor Switched Reactor

TSR

Voltage Transformer / Capacitor VT / Wound VT

VT / CVT / WVT

TABLE 5 SWITCHGEAR NUMBERING AND NOMENCLATURE (Excluding LV Metal Enclosed) CLASS

TITLE

SYMBOLS 275 kV

132 kV

L.V

Switch Disconnector

400 kV X*00

L*0

*00

*L0

Line Earth Switching

X*01

L*1

*01

*L1

By-Pass Disconnector

X*02

L*2

*02

*L2

Line Disconnector

X*03

L*3

*03

*L3

Main Busbar Selector Disconnector

X*04

L*4

*04

*L4

Circuit Breaker

X*05

L*5

*05

*L5

Reserve Busbar Selector Disconnector

X*06

L*6

*06

*L6

Circuit Breaker Disconnector (Busbar Side)

X*07

L*7

*07

*L7

Transformer High

Transformer Circuit Breaker

X*10

H*0

*10

*H0

Voltage Side

Transformer Earthing Switch Transformer By-Pass Disconnector

X*11 X*12

H*1 H*2

*11 *12

*H1 *H2

Transformer Disconnector

X*13

H*3

*13

*H3


X*14

H*4

*14

*H4

Switch Disconnector

X*15

H*5

*15

*H5

Reserve Busbar Selector Disconnector Main Bus Section Circuit Breaker

X*16 X*20

H*6 S*0

*16 *20

*H6 *S0

Main Bus Section Earthing Switch

X*21

S*1

*21

*S1

Main Bus Section Disconnector (No. 1 Side) Switch Disconnector

X*24

S*4

*24

*S4

X*25

S*5

*25

*S5

Mesh Opening Corner Disconnector

X*26

S*6

*26

*S6

Main Bus Section Disconnector (No. 2 Side)

X*28

S*8

*28

*S8

Reserve Bus

Reserve Bus Section Circuit Breaker

X*60

P*0

*60

*P0

Section

Reserve Bus Section Earthing Switch

X*61

P*1

*61

*P1

Reserve Bus Section Disconnection (No.1 Side)

X*66

P*6

*66

*P6

Reserve Bus Section Disconnector (No. Side)

X*69

P*9

*69

*P9

Lines

Main Bus Section



Bus Coupler

Uncontrolled when Printed Bus Coupler Circuit Breaker

X*30 X*31

W*0 W*1

*30 *31

*W0 *W1

X*34

W*4

*34

*W4

Bus Coupler Reserve Busbar Disconnector

X*36

W *6

*36

*W6

Reactor Circuit Breaker

X*40

R*0

*40

*R0

Reactor Earthing Switch

X*41

R*1

*41

*R1

Line Disconnector

X*43

R*3

*43

*R3

Main Busbar Selector Disconnector (1st choice)

X*44

R*4

*44

*R4

2nd Reactor Circuit Breaker where 2 per Reactor

X*45

R*5

*45

*R5

Reserve Busbar Selector Disconnector (1st Choice)

X*46

R*6

*46

*R6

Circuit Breaker Disconnector (Busbar Side)

X*47

R*7

*47

*R7

Main Busbar Selector Disconnector (2nd Choice)

X*48

R*8

*48

*R8

Reactor Tie Busbar Disconnector or Reserve Busbar Selector Disconnector (2nd Choice)

X*49

R*9

*49

*R9

Static Shunt

Reactor/Capacitor Circuit Breaker

X*50

*0

*50

*K0

Compensator

Reactor/Capacitor Earthing Switch Reactor/Capacitor Disconnector

X*51 X*53

*1 *3

*51 *53

*K1 *K3

Reactor/Capacitor Switch Disconnector

X*55

*5

*55

*K5

Bus Coupler Earthing Switch Bus Coupler Main Busbar Disconnector

Quad Booster

Transformer Low

Transformer Circuit Breaker

T*0

*80

*T0

Voltage Side

Transformer Earthing Switch Transformer Disconnector

T*1 T*3

*81 *83

*T1 *T3


T*4

*84

*T4

Switch Disconnector

T*5

*85

*T5

Reserve Busbar Selector Disconnector Generator Circuit Breaker. (Where 2 per generator, Main Busbar)

X*90

T*6 M*0

*86 *90

*T6 *M0

Generator Transformer Earthing Switch

X*91

M*1

*91

*M1

By-Pass Disconnector

X*92

M*2

*92

*M2

Generator Transformer Disconnector Main Busbar Selector Disconnector

X*93 X*94

M*3 M*4

*93 *94

*M3 *M4

Generator Circuit Breaker where 2 per generator (Reserve Busbar) or Switch Disconnector

X*95

M*5

*95

*M5

Reserve Busbar Selector Disconnector

X*96

M*6

*96

*M6

Circuit Breaker Disconnector (Busbar Side) Synchronous Compensator - 'Main Circuit Breaker'

X*97

M*7

*97

*M7 *M01

Generators

Synchronous Compensators

Synchronous Compensator - 'Starting' Circuit Breaker

*M02

Synchronous Compensator - 'Running' Circuit Breaker

*M03


Uncontrolled when Printed Miscellaneous Equipment


Synchronous Compensator Disconnector Synchronous Compensator Earthing Switch

*M3 *M1

Disconnector Associated with certain miscellaneous auxiliary equipment e.g VT's Fault Thrower

*A3 FT*

*Denotes sequence of switch groups Excluding Supergrid and Grid Transformer Circuit feeding a Bulk Supply Point. These circuit breakers do not have a number but should be respectively identified as Supergrid* and Grid*

SEE DIAGRAMS 1 - 11 FOR ILLUSTRATIONS OF BOTH NUMBERING AND NOMENCLATURE




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