ENGINEERING DESIGN STANDARD - Document … DESIGN STANDARD ... Table 8 – Settings for Merlin Gerin...

Document Number: EDS 05-2010

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ENGINEERING DESIGN STANDARD

EDS 05-2010

MAIN SUBSTATION FEEDER AND RING MAIN UNIT PROTECTION SETTINGS (LPN)

Network(s): LPN

Summary: This standard describes the protection settings for main substation feeders and ring main units in the LPN area.

Owner: Kevin Burt Date: 02/12/2015

Approved By: Barry Hatton Approved Date: 08/01/2015

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 issue.

Applicable To

UK Power Networks External

All UK Power Networks G81 Website

Asset Management Contractors

Capital Programme ICPs/IDNOs

Connections Meter Operators

HSS&TT

Network Operations

UK Power Networks Services

Other


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© UK Power Networks 2016 All rights reserved 2 of 14

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Revision Record

Version 4.0 Review Date 08/01/2019

Date 02/12/2015 Author Kevin Burt

Why has the document been updated – Periodic review

What has changed – No content changes

Document transferred onto a new template and rules applied


Date 04/09/2012 Author Lee Strachan

Document reviewed for publishing on G81 website


Date 25/08/2011 Author Chris Anderson

Reclassified from EI to EDS


Date 19/08/2010 Author David G Edwards

Rebranded, reviewed and review date extended

Version 2.0 Review Date


TLF ratings and revised ACB protection settings added Tables (6A and 11A)

Version 1.0 Review Date


Original, based on Protection Standard Number E 7/6 P 6/1 revision 4. Original no. EI 05-0046


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Contents

1 Introduction ............................................................................................................. 4

2 Scope ....................................................................................................................... 4

3 Glossary and Abbreviations ................................................................................... 4

4 Main Substation Feeder Settings ........................................................................... 4

5 Secondary Distribution Transformers ................................................................... 4

5.1 Transformer Overcurrent Protection .......................................................................... 4

5.2 Transformer Earth Fault Protection ............................................................................ 4

6 HV Supplies ............................................................................................................. 5

6.1 HV Supplies to the Customer’s HV Switchboard ........................................................ 5

6.1.1 Overcurrent Protection .............................................................................................. 5

6.1.2 Earth Fault Protection ................................................................................................ 5

Tables

Table 1 – Main Substation Feeder Settings ........................................................................... 6

Table 2 – Ring Circuit Breaker and Service Circuit Breaker – Electromechanical .................. 6

Table 3 – Ring Circuit Breaker and Service Circuit Breaker – VIP 200/300 ........................... 7

Table 4 – SEPAM 1000 ......................................................................................................... 7

Table 5 – SEPAM 1000+. ...................................................................................................... 8

Table 6 – Overcurrent Protection of Distribution Transformers (Glass Barrel TLF Fuse Links) ................................................................................................................... 9

Table 7 – Overcurrent Protection of Distribution Transformers (Tagged TLF Fuse Links) ... 11

Table 8 – Settings for Merlin Gerin Masterpact ACB Control Unit STR58U (Glass Barrel TLF Fuse Links) ................................................................................................. 11

Table 9 – Masterpact ACB STR 58U - 1200/1600A ACB with MODULE 1600A (Glass Barrel TLF Fuse Links) ...................................................................................... 12

Table 10 – Masterpact ACB STR 58U – 2000A ACB with MODULE 2000A (Glass Barrel TLF Fuse Links) ............................................................................................. 12

Table 11 – 1600A and 2000A Module (Glass Barrel TLF Fuse Links) ................................. 12

Table 12 – Micrologic NW16/20 H1 – 1600/2000A Module (Glass Barrel TLF Fuse Links) . 13

Table 13 – Micrologic NW16/20 H1 – 1600/2000A Module (Tagged TLF) ........................... 13

Table 14 – Sensitive Earth Fault Settings ............................................................................ 13

Table 15 – Overcurrent Protection of HV Supplies (refer to Section 6.1.1) .......................... 14

Table 16 – Falcon Alpha RMU Overcurrent Trip Times Versus Fault Current...................... 14


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1 Introduction

This standard describes protection settings for main substation feeders and ring main units in the UK Power Networks (UKPN) LPN region.

2 Scope

This standard only applies to the London Power Network (LPN) area.

3 Glossary and Abbreviations

Term Definition

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 Main Substation Feeder Settings

The overcurrent and earth fault settings shall be as listed in Table 1 unless otherwise agreed with UKPN Asset Management.

5 Secondary Distribution Transformers

5.1 Transformer Overcurrent Protection

The rating of the time-limit fuse-links or the type of thermal protection modules for overcurrent protection of secondary distribution transformers applied at ring main units and their associated air circuit breakers shall be as listed in Table 6.

5.2 Transformer Earth Fault Protection

Instantaneous sensitive earth fault protection with sensitivities as declared in Table 14 is inherent in the design of all but:

The Falcon Alpha units (original Falcon units) where it is provided, when specified, via dedicated core balanced current transformers; and

Switch fuses, where it is not good practice to provide it.

It should be noted that such a provision is not normally present on transformer mounted Falcon Alpha units.


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6 HV Supplies

Where an HV supply is connected directly to the customer’s own transformer, of which the rating and winding arrangement and impedance are similar to the Company’s distribution transformers, then Section 5 of this document shall apply. For transformers not so identifiable, advice should be sought from UKPN Asset Management. Where relays are used to afford protection then the settings shall be as in Table 1, Table 2 and Table 3.

If Microprocessor relays are used, reference should be made to UKPN Asset Management with full details of the proposed installation so that individual settings can be supplied.

6.1 HV Supplies to the Customer’s HV Switchboard

6.1.1 Overcurrent Protection

Discrimination with the customer’s own equipment, other than fuses for HV faults, is not feasible with ring main units protected by time fuse links. Discrimination with the customer’s equipment can be afforded by use of protective relays. Relays installed with characteristics based on the standard inverse BS 142 curve shall have settings as in Table 2. Relays supplied with adjustable complex curves, may need special treatment and shall be referred to UKPN Asset Management.

In some cases the customer will not require discrimination with the service and thus it may be possible to use time fuses for overcurrent (and instantaneous protection for earth faults when applicable). The rating of the time fuse link and thermal modules for these cases shall be as listed in Table 15.

Limited discrimination is possible with units protected by thermal protection modules, and Table 16 relates to Falcon Alpha overcurrent trip times to fault current as an application guide. In cases of doubt advice should be sought from UKPN Asset Management. Where Falcon Alpha units are used to provide such a supply then the module shall be as specified in Table 15.

6.1.2 Earth Fault Protection

Earth fault protection can be provided by protection relays and for the standard inverse curve relay settings refer to Table 2 and Table 3. In the case of Microprocessor relays refer to UKPN Asset Management.

Instantaneous sensitive earth fault protection with sensitivities as declared in Table 14 is inherent in the design of all but;

The Falcon Alpha ring main unit, where it is provided, when specified, via a dedicated core balance current transformer; and

Switch fuses, where it is not provided. The switch fuse will, however, discriminate with the main substation earth fault relay for earth faults exceeding 800A downstream of the ring main unit.


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Where Falcon Alpha ring main units are installed, and there is a requirement by the customer for discrimination, no instantaneous earth fault protection is needed and the following applies:

For applications (see Table 15) using the ‘D’ module, no specific earth fault protection is necessary because the ‘D’ module discriminates with the main substation earth fault relay for earth faults downstream of the ring main unit;

For applications using the ‘F’ module, a separate IDMT earth fault current relay fed from the core balance current transformer and set at 120 primary amperes 0.15 time multiplier, tripping via the shunt trip coil should be installed. This will prevent the main substation earth fault relay from operating before the ring main unit for earth faults downstream of the ring main unit.

Table 1 – Main Substation Feeder Settings

High Set Overcurrent when Provided

IDMT Overcurrent IDMT Earth Fault

Feeders without HV customers or where HV supplies are afforded to customers’ own distribution transformers

2400-3200A 600A 0.2TM 200A 0.2TM

Feeders from which at least one HV supply is afforded to customer’s HV switchboard

Not deployed 600A 0.35TM 200A 0.35TM

Table 2 – Ring Circuit Breaker and Service Circuit Breaker – Electromechanical

Method of Supply Ring CB Service CB

IDMT Overcurrent

IDMT Earth Fault

IDMT Overcurrent

IDMT Earth Fault

Unit protected two feeders in parallel

450A 0.15TM 150A 0.15TM

Unit protected three feeders in parallel

600A 0.15TM 200A 0.15TM 450A 0.15TM 150A 0.15TM

Directional protected two feeders in parallel

600A 0.15TM 200A 0.15TM 450A 0.15TM 150A 0.15TM

Radial Feed 450A 0.15TM 150A 0.15TM


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Table 3 – Ring Circuit Breaker and Service Circuit Breaker – VIP 200/300

VIP 200/300

CT Ratio

200/1 800/1 800/1

Position Service Service Ring

O/C SI 200A, t=0.4s

(equivalent to tms=0.135)

SI 448A, t=0.4s


SI 576A,T=0.4s


E/F SI 140A, t=0.4s


SI 128A, t=0.4s


SI 196A, t=0.4s


VIP 300

CT Ratio

400/1 Not suitable for Ring Busters

Position Service

O/C SI 400A, t=0.4s


E/F SI 160A, t=0.4s


Notes: 1. VIP Relays are self powered from the CT, the maximum setting is 100% of the CT primary rating. 2. As from September 2003 YRM switchgear came with 400/1 CTs.

Table 4 – SEPAM 1000

Position Service Service Ring

CT Ratio 200/1 600/1 600/1

Overcurrent SI 440A, t=0.4s


SI 450A, t=0.4s


SI 600A,T=0.4s


Earth Fault SI 150A, t=0.4s


SI 150A, t=0.4s


SI 200A, t=0.4s



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Table 5 – SEPAM 1000+.

Position Service

SELECT A+B

Ring

SELECT A+B

CT Ratio 600/1 600/1

Overcurrent SIT 450, t=0.450s


SIT 600A,T=0.450s


E/F SIT 150A, t=0.450s


SIT 200A, t=0.450s


Notes: 1. For all the above settings refer to Asset Management. 2. Special applications will be considered to assist customers with their downstream protection grading. Such

requests shall be sent to Asset Management and if abnormal settings are to be issued for application to network protection, a note of this abnormality shall be attached in the control graphics system, adjacent to the substation concerned.

3. Settings and logic for all microprocessor relays are the responsibility of Programme Delivery, Protection Applications.


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Table 6 – Overcurrent Protection of Distribution Transformers (Glass Barrel TLF Fuse Links)

Equipment CT Ratio

Voltage Transformer Ratings

500kVA 750/800kVA 1000kVA 2x500kVA 2 x 750/800kVA

Brush Falcon ALPHA RMU

8/1 6.6kV D D (*3) - - -

(*1) 11kV C D D D (*2) -

19/1 6.6kV - - F E (*2) -

(*1) 11kV - - - - E (*2)

Brush Falcon BETA RMU

50/5 6.6kV 10A - - - -

11kV 7.5A - see table 8

10A - - -

100/5 6.6kV - 7.5A 10A 10A -

11kV - - 7.5A 7.5A 10A

Yorkshire (*6) Switchgear Ringmaster RMU MK1.5

75/5 6.6kV 7.5A (*4) - see table 8

10A (*4) 10A (*4) 10 (*2) -

11kV 5A 7.5A 10A 7.5 (*2)

Yorkshire Switchgear Ringmaster RMU MK 2

50/5 6.6kV 10A - - - -


10A - - -

100/5 6.6kV - 7.5A 10A 10A -

11kV - - 7.5 7.5A 10A

Long & (*7) Crawford (*8) LCGT RMU (Switchfuse)

- 6.6kV 100(80)A 140(100)A 140(100)A

- -

11kV 63(50)A 80(63)A 100(80)A - -

Lucy (*8) SFRMU CF1 Switchfuse

- 6.6kV 80A 125A - - -

- 11kV 50A 80A 100A - -

Lucy SCRMU

70/5 6.6kV 10A - - - -


10A - - -

100/5 6.6kV - 7.5A 10A 10A -

11kV - - 7.5A 7.5 10A


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Equipment CT Ratio

Voltage Transformer Ratings

500kVA 750/800kVA 1000kVA 2x500kVA 2 x 750/800kVA

ABB Sentinel RMU

50/5 6.6kV 10A - - - -


10A - - -

100/5 6.6kV - 7.5A 10A 10A -

11kV - - 7.5A 7.5A 10A

All Other RMUs

50/5 6.6kV 10A - - - -


10A - - -

80/5 6.6kV 7.5A - see table 8

10A - - -

11kV 5A 7.5A 10A 10A 10A

100/5 6.6kV - 7.5A (*4) 10A 10A -

11kV - - 7.5A 7.5A 10A

Masterpack ACB

Standard settings set at factory for 1200 & 1600 amp units see Table 9. Any other units need to be referred to System Development Protection

ACB

800/5 0.433kV 7.5A - - 7.5A -

1200/5 0.433kV 5A 7.5A - 5A 7.5A

1600/5 0.433kV - - 7.5A - -

Notes: 1. On the Falcon Alpha RMU, current transformers are matched to particular types of protection modules.

Unless specifically agreed with the MPL Protection Section, module types must not be interchanged between the two CT types. The CTs are mounted inside the SF6 chamber which must be returned to the manufacturer if a change is necessary.

2. In the interests of faster fault clearance, discrimination across the distribution transformer is sacrificed if the LV windings are paralleled.

3. Some loss of discrimination across the distribution transformer results from avoiding a CT change on uprating to 11kV operation.

4. Discrimination across the transformer is sacrificed in the interest of faster fault clearance. 5. This ratio is not available on Yorkshire Ringmaster, Lucy SCRMU, or Falcon BETA RMUs. 6. Yorkshire Ringmasters, pre-MK 2 on the LPN network, are referred to as MK 1.5. 7. Figures quoted are fuse rating in oil. Ratings in air are shown in brackets. 8. Discrimination with LV ACBs is not guaranteed and should not be used with solidly interconnected LV

systems. 9. Discrimination between Falcon ALPHA RMUs and MSS is not guaranteed for faults between the RMU and

its transformer. 10. There is no overload factor on this application. 11. For applications other than the above, advice should be sought from Asset Management


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Table 7 – Overcurrent Protection of Distribution Transformers (Tagged TLF Fuse Links)

Voltage Transformer rating CT ratio TLF rating SAP code

11 kV

500 kVA 40/5 N/A N/A

50/5 N/A N/A

800 kVA 80/5 15 A 11947C

100/5 15 A 11947C

1000 kVA 80/5 15 A 11947C

100/5 15 A 11947C

Note: For existing distribution substations with a 500kVA transformer where HV switchgear is to be changed and the 500kVA transformer is to be retained, it is not possible to grade tag-type TLF’s with the LV fuses. Therefore, when replacement of the HV equipment is necessary, complete the following:

Install a Lucy Sabre VRN2A RMU.

Retro fit clips for glass barrel-type TLFs.

Install 10A glass barrel-type TLFs.

Table 8 – Settings for Merlin Gerin Masterpact ACB Control Unit STR58U (Glass Barrel TLF Fuse Links)

Characteristics Setting Value Dial Position Dial Position

Long Time Pick Up LT 1600A IO = 1 Ir =1

Long Time Time Delay LT 15 s tr = 15 -

Short Time Pick Up ST 2400A Im =1.5 -

Short Time Time Delay ST

0.2 s tm = 0.2 -

I2t ON tm Dial Set Clockwise to 0.2

Instantaneous Pick Up 12800A I = 8 -

Notes: 1. For transformers of all sizes associated with 1200A and 1600A ACBs using 1600A sensors. 2. These settings grade with downstream J400A fuses. They will not grade with J-type distribution fuses of

higher rating. 3. Upstream RMU 7.5A TLFs with 50/5, 70/5, 75/5 and 80/5 CTs must be changed to 10A TLFs (Glass Barrel

TLF Fuse Links).


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Table 9 – Masterpact ACB STR 58U - 1200/1600A ACB with MODULE 1600A (Glass Barrel TLF Fuse Links)

1200/1600amp ACB with MODULE 1600A

Transformer Size

TLF Min CT ratio

Io Ir tr Im tm I2t I

500kVA 50/5 1 1 15 1.5 0.2 on 12

800kVA 80/5 1 1 15 1.5 0.2 on 14

800kVA 75/5 1 1 15 1.5 0.2 on 14

1000kVA 100/5 1 1 15 1.5 0.2 0n 22

Notes: 1. Settings to apply for transformers with services having 630A or 800A fuses and on interconnected areas

using 500A fuses. 2. Always use 10A TLFs (Glass Barrel TLF Fuse Links).

Table 10 – Masterpact ACB STR 58U – 2000A ACB with MODULE 2000A (Glass Barrel TLF Fuse Links)

Transformer Size

CT Ratio

Io Ir tr Im tm I2t I

1000kVA 100/5 1 1 15 1.5 0.2 0n 17

Notes: 1. Where two transformers are connected in parallel at LV from different feeders, in the event of an earth fault

on one feeder, there is the possibility of the feeder being back fed by the other transformer. 2. This will occur with radial LV networks, where hold-up performance is poor in fully interconnected LV

networks. 3. This arrangement is to coordinate with reverse power relays and parasitic trip units.

Table 11 – 1600A and 2000A Module (Glass Barrel TLF Fuse Links)

Module Transformer Size

CT ratio Io Ir tr Im tm I2t I

1600A 2 x 1000kVA 100/5 1 1 15 3 0.2 on 22

2000A 2 x 1000kVA 100/5 1 1 15 3 0.2 on 17

Notes: 1. Masterpact NM ACB. 2. Micrologic 5.0A. 3. Settings to apply for transformers with services having 630A or 800A fuses and on interconnected areas

using 500A fuses. 4. Always use 10A TLFs (Glass Barrel TLF Fuse Links)


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Table 12 – Micrologic NW16/20 H1 – 1600/2000A Module (Glass Barrel TLF Fuse Links)

Protection settings to be applied when grading with a glass barreled TLF fuse link. Refer to Table 6 – Over-current protection of distribution transformers (Glass Barrel TLF)


TLF Min CT Ratio

Ir tr Isd tsd Iinst

Micrologic NW16 H1 - 1600A

All 100/5 1.00 4.0 8.00 0.1+I2t 15


All 100/5 1.00 4.0 6.00 0.1+I2t 15

Note: For all Micrologic these settings are factory set. They will need to be checked at the time of commissioning.

Table 13 – Micrologic NW16/20 H1 – 1600/2000A Module (Tagged TLF)

Protection settings to be applied when grading with a Tagged TLF fuse link. Refer to Table 7 – Over-current protection of distribution transformers (Tagged TLF).


TLF Min CT Ratio

Ir tr Isd tsd Iinst


All 100/5 1.00 12 6.00 0.1+I2t 15


All 100/5 1.00 4.0 4.00 0.1+I2t 15

Note: For all Micrologic these settings are factory set. They will need to be checked at the time of commissioning.

Table 14 – Sensitive Earth Fault Settings

Equipment CT Ratio Sensitive Earth Fault Setting

Brush ALPHA RMU Core balance

400/5

30 A

Brush BETA RMU 50/5

100/5

30 A

40 A

Yorkshire Ringmaster MK1.5 75/5 20A

Yorkshire Ringmaster MK2 50/5

100/5

20 A

25 A

Lucy SCRMU 70/5

100/5

20 A

25 A

ABB

Sentinel RMU

50/5

100/5

20 A - 27 A

28 A - 35 A

All RMUs except Switch Fuses and the above

50/5

80/5

100/5

20 A

20 A

25 A


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Table 15 – Overcurrent Protection of HV Supplies (refer to Section 6.1.1)

Equipment Load MVA at 6.6kV MVA at 11kV Module/fuse CT

Brush Falcon ALPHA

0-100A 0-1.1 0-1.9 d (1) 8/1

100-180A 1.1-2.0 1.9-3.4 F (1) 19/1

>180A >2.0 >3.4 Use extensible switchgear

Yorkshire Switchgear Ringmaster

0-150A 0-1.7 0-2.85 10A 75/5 MK1

0-200A 0-2.28 0-3.8 10A 100/5 MK2

MK2 only for downstream discrimination using relays

Long & Crawford LCGT Sw/fuse

0-80A 0.9 1.5 100(80)A

(7) -

Lucy SFRMU-CF1 Sw/fuse

0-83A 0.95 1.58 125A -

All RMUs except as above

0-100A 0-1.1 0-1.9 10A 100/5

Notes: 1. For downstream discrimination a relay should be used. Refer to Asset Management for VIP200 Settings. 2. Refer to Section 6.1.2 for earth fault protection requirements.

Table 16 – Falcon Alpha RMU Overcurrent Trip Times Versus Fault Current

Fault Current (A) D Module (s) F Module (s)

1000 0.8 1.0

2000 0.45 0.4

4000 0.3 0.22

6000 0.25 0.17

8000 0.22 0.15

10000 0.2 0.13

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