IEC TS 60871-3:2015

Shunt capacitors for a.c. power systems having a rated voltage above 1000 V - Part 3: Protection of shunt capacitors and shunt capacitor banks

IEC/TS 60871-3:2015(E) which is a technical specification, gives guidance on the protection of shunt capacitors and shunt capacitor banks. it applies to capacitors according to IEC 60871-1. This second edition cancels and replaces the first edition published in 2005. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- Clearer writing of formulas on energy limitation for expulsion fuses;
- Updated normative references and bibliography;
- A new clause for synchronized switching has been added. Keywords: shunt capacitors, shunt capacitor banks

General Information

• Status: Published
• Publication Date: 21-Aug-2023
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.240.99 - Other equipment related to power transmission and distribution networks
• ICS: 31.060.70 - Power capacitors
• Technical Committee: TC 33 - Power capacitors and their applications
• Drafting Committee: MT 19 - TC 33/MT 19
• Current Stage: PPUB - Publication issued
• Start Date: 15-Oct-2015
• Completion Date: 25-Jun-2015

Relations

• Amended By: IEC TS 60871-3:2015/AMD1:2023 - Amendment 1 - Shunt capacitors for AC power systems having a rated voltage above 1 000 V - Part 3: Protection of shunt capacitors and shunt capacitor banks
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC TS 60871-3 ®
Edition 2.0 2015-06
TECHNICAL
SPECIFICATION
Shunt capacitors for AC power systems having a rated voltage above 1 000 V –
Part 3: Protection of shunt capacitors and shunt capacitor banks
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

IEC Central Office Tel.: [phone]
3, rue de Varembé Fax: [phone]
CH-1211 Geneva 20 [e-mail]
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

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IEC TS 60871-3 ®
Edition 2.0 2015-06
TECHNICAL
SPECIFICATION
Shunt capacitors for AC power systems having a rated voltage above 1 000 V –

Part 3: Protection of shunt capacitors and shunt capacitor banks

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.99; 31.060.70 ISBN 978-2-8322-2755-8

– 2 – IEC TS 60871-3:2015 © IEC 2015
CONTENTS
FOREWORD .5
1 Scope .7
2 Normative references .7
3 Terms and definitions .7
4 Internal fuses .7
4.1 General .7
4.2 Fuse characteristics .8
4.2.1 Rated current .8
4.2.2 Rated discharge capability .8
4.2.3 Disconnecting capability .8
4.2.4 Voltage withstand capability after operation .8
4.3 Influence of capacitor element configuration on capacitor life.8
4.3.1 Capacitor with all elements connected in parallel .8
4.3.2 Capacitor with elements connected in series and parallel .8
5 External fuses .8
5.1 General .8
5.2 Fuse characteristics .9
5.2.1 Rated current .9
5.2.2 Rated voltage .9
5.2.3 Time-current characteristics .9
5.2.4 Discharge capability . 10
5.3 Fuse types . 10
5.3.1 General . 10
5.3.2 Expulsion fuses . 10
5.3.3 Current-limiting fuses . 11
5.3.4 Combination current-limiting/expulsion fuses . 11
5.4 Influence of capacitor bank configuration on fuse selection . 11
5.4.1 Single series section grounded star and delta banks . 11
5.4.2 Single series section ungrounded star banks . 11
5.4.3 Multiple series section banks . 11
5.5 Coordination with case rupture curves . 11
6 Unbalance detection . 12
6.1 Operation . 12
6.2 Types of unbalance protection . 12
6.2.1 Neutral current (Figure 3) . 12
6.2.2 Neutral voltage (Figure 4) . 12
6.2.3 Current unbalance between neutrals (Figure 5) . 13
6.2.4 Phase voltage unbalance (Figure 6) . 13
6.2.5 Voltage difference (Figure 7) . 13
6.2.6 Current unbalance in bridge connection (Figure 8) . 13
6.3 Current and voltage transformers . 13
6.3.1 Current transformers . 13
6.3.2 Voltage transformers . 14
6.4 Relays and protection settings . 14
6.5 Sensitivity . 14
6.6 Initial unbalance . 15

7 Overload current . 15
7.1 Operation . 15
7.2 Protective arrangement . 15
7.3 Current transformers . 15
7.4 Relays . 15
7.5 Protective settings . 16
8 Over and undervoltage . 16
8.1 Operation . 16
8.2 Overvoltage protection . 16
8.3 Undervoltage protection . 16
8.4 Reclosing . 16
9 Other protection . 17
9.1 Surge arresters . 17
9.1.1 General . 17
9.1.2 Operation . 17
9.1.3 Lightning transients. 17
9.1.4 Switching transients . 17
9.1.5 Temporary overvoltages . 17
9.1.6 Rated voltage . 17
9.1.7 Energy absorption . 18
9.2 Damping devices . 18
9.2.1 Capacitor switching . 18
9.2.2 Inrush currents . 18
9.2.3 Voltage transients . 19
9.2.4 Ratings . 19
9.3 Synchronized switching . 19
9.3.1 Operation . 19
9.3.2 Breaker contacts delay. 19
10 Safety . 19
10.1 Discharging devices . 19
10.1.1 General . 19
10.1.2 Internal resistors . 20
10.1.3 External discharge devices . 20
10.1.4 Discharging after disconnection . 20
10.2 Dead metallic parts . 20
Bibliography . 25

Figure 1 – Fuse types . 10
Figure 2 – Typical case rupture curves for approximately 30 000 cm³ case volume . 21
Figure 3 – Star connection with the neutral grounded through a current transformer . 21
Figure 4 – Star connection with voltage transformer between neutral and ground . 21
Figure 5 – Star connection with ungrounded neutral and voltage transformers
connected in an open delta . 22
Figure 6 – Double-star connection with ungrounded neutral . 22
Figure 7 – Star connection with grounded neutral and voltage transformers connected
in differential measurement . 22
Figure 8 – Bridge connection . 22

– 4 – IEC TS 60871-3:2015 © IEC 2015
Figure 9 – Line overcurrent relays for capacitor bank, grounded . 22
Figure 10 – Line overcurrent relays for capacit
...

IEC TS 60871-3 ®
Edition 2.1 2023-08
CONSOLIDATED VERSION
TECHNICAL
SPECIFICATION
colour
inside
Shunt capacitors for AC power systems having a rated voltage above 1 000 V –
Part 3: Protection of shunt capacitors and shunt capacitor banks
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
IEC Secretariat Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
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and withdrawn publications.
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details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
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(IEV) online.
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If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: [e-mail].
IEC TS 60871-3 ®
Edition 2.1 2023-08
CONSOLIDATED VERSION
TECHNICAL
SPECIFICATION
colour
inside
Shunt capacitors for AC power systems having a rated voltage above 1 000 V –
Part 3: Protection of shunt capacitors and shunt capacitor banks
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.240.99; 31.060.70 ISBN 978-2-8322-7449-1

IEC TS 60871-3 ®
Edition 2.1 2023-08
CONSOLIDATED VERSION
REDLINE VERSION
colour
inside
Shunt capacitors for AC power systems having a rated voltage above 1 000 V –
Part 3: Protection of shunt capacitors and shunt capacitor banks
– 2 – IEC TS 60871-3:2015+AMD1:2023 CSV
© IEC 2023
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Internal fuses. 7
4.1 General . 7
4.2 Fuse characteristics . 8
4.2.1 Rated current . 8
4.2.2 Rated discharge capability . 8
4.2.3 Disconnecting capability . 8
4.2.4 Voltage withstand capability after operation . 8
4.3 Influence of capacitor element configuration on capacitor life . 8
4.3.1 Capacitor with all elements connected in parallel . 8
4.3.2 Capacitor with elements connected in series and parallel . 8
5 External fuses . 8
5.1 General . 8
5.2 Fuse characteristics . 9
5.2.1 Rated current . 9
5.2.2 Rated voltage . 9
5.2.3 Time-current characteristics . 9
5.2.4 Discharge capability . 10
5.3 Fuse types . 10
5.3.1 General . 10
5.3.2 Expulsion fuses . 10
5.3.3 Current-limiting fuses. 11
5.3.4 Combination current-limiting/expulsion fuses . 11
5.4 Influence of capacitor bank configuration on fuse selection . 11
5.4.1 Single series section grounded star and delta banks. 11
5.4.2 Single series section ungrounded star banks . 11
5.4.3 Multiple series section banks . 11
5.5 Coordination with case rupture curves . 11
6 Unbalance detection . 12
6.1 Operation . 12
6.2 Types of unbalance protection . 12
6.2.1 Neutral current (Figure 3) . 12
6.2.2 Neutral voltage (Figure 4) . 12
6.2.3 Current unbalance between neutrals (Figure 5) . 13
6.2.4 Phase voltage unbalance (Figure 6) . 13
6.2.5 Voltage difference (Figure 7) . 13
6.2.6 Current unbalance in bridge connection (Figure 8) . 13
6.3 Current and voltage transformers . 13
6.3.1 Current transformers. 13
6.3.2 Voltage transformers . 14
6.4 Relays and protection settings . 14
6.5 Sensitivity . 14
6.6 Initial unbalance . 15

© IEC 2023
6.7 Calculation of the unbalance relay’s settings . 15
7 Overload current . 15
7.1 Operation . 15
7.2 Protective arrangement . 15
7.3 Current transformers . 16
7.4 Relays . 16
7.5 Protective settings . 16
8 Over and undervoltage . 16
8.1 Operation . 16
8.2 Overvoltage protection . 17
8.3 Undervoltage protection . 17
8.4 Reclosing . 17
9 Other protection. 17
9.1 Surge arresters . 17
9.1.1 General . 17
9.1.2 Operation . 17
9.1.3 Lightning transients . 17
9.1.4 Switching transients . 18
9.1.5 Temporary overvoltages . 18
9.1.6 Rated voltage . 18
9.1.7 Energy absorption . 18
9.2 Damping devices . 18
9.2.1 Capacitor switching . 18
9.2.2 Inrush currents . 18
9.2.3 Voltage transients . 19
9.2.4 Ratings . 19
9.3 Synchronized switching . 19
9.3.1 Operation . 19
9.3.2 Breaker contacts delay . 20
10 Safety . 20
10.1 Discharging devices . 20
10.1.1 General . 20
10.1.2 Internal resistors . 20
10.1.3 External discharge devices . 20
10.1.4 Discharging after disconnection . 20
10.2 Dead metallic parts . 21
Bibliography . 26

Figure 1 – Fuse types . 10
Figure 2 – Typical case rupture curves for approximately 30 000 cm³ case volume . 22
Figure 3 – Star connection with the neutral grounded through a current transformer . 22
Figure 4 – Star connection with voltage transformer between neutral and ground . 22
Figure 5 – Star connection with ungrounded neutral and voltage transformers
connected in an open delta . 23
Figure 6 – Double-star connection with ungrounded neutral . 23
Figure 7 – Star connection with grounded neutral and voltage transformers connected
in differential measurement . 23

– 4 – IEC TS 60871-3:2015+AMD1:2023 CSV
© IEC 2023
Figure 8 – Bridge connection .
...