1、BSI Standards Publication Shunt capacitors for AC power systems having a rated voltage above 1 000 V Part 3: Protection of shunt capacitors and shunt capacitor banks PD IEC/TS 60871-3:2015National foreword This Published Document is the UK implementation of IEC/TS 60871-3:2015. The UK participation
2、in its preparation was entrusted to Technical Committee PEL/33, Power capacitors. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its
3、correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 85306 7 ICS 29.240.99; 31.060.70 Compliance with a British Standard cannot confer immunity from legal obligations. This Published Document was published under the authority of the Stan
4、dards Policy and Strategy Committee on 31 July 2015. Amendments/corrigenda issued since publication Date Text affected PUBLISHED DOCUMENT PD IEC/TS 60871-3:2015 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
5、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 Registered trademark of the International Electrotechnical Commission Warning! Make sure that you obtained this publication from an authorized distrib
6、utor. PD IEC/TS 60871-3:2015 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
7、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
8、 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 ban
9、k 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 unbala
10、nce 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 C
11、urrent 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 PD IEC/TS 60871-3:2015IEC TS 60871-3:2015 IEC 2015 3 7 Overload current . 15 7.1 Operation 15 7.2 Protective arrangement
12、. 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 t
13、ransients 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 1
14、9 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 ca
15、se rupture curves for approximately 30 000 cm 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 transforme
16、rs 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 PD IEC/TS 60871-3:2015 4 IEC TS 60871-3:2015 IEC 2015 Figure
17、9 Line overcurrent relays for capacitor bank, grounded 22 Figure 10 Line overcurrent relays for capacitor bank, ungrounded 23 Table 1 Melting currents for type-K (fast) fuse links, in amperes . 23 Table 2 Melting currents for type-T (slow) fuse links, in amperes 24 PD IEC/TS 60871-3:2015IEC TS 60871
18、-3:2015 IEC 2015 5 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ SHUNT CAPACITORS FOR AC POWER SYSTEMS HAVING A RATED VOLTAGE ABOVE 1 000 V Part 3: Protection of shunt capacitors and shunt capacitor banks FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for s
19、tandardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes
20、 International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may parti
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22、tween the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees. 3) IEC Publicat
23、ions have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for
24、any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the correspondi
25、ng national or regional publication shall be clearly indicated in the latter. 5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any se
26、rvices carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC N
27、ational Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications. 8) Attentio
28、n is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC s
29、hall not be held responsible for identifying any or all such patent rights. The main task of IEC technical committees is to prepare International Standards. In exceptional circumstances, a technical committee may propose the publication of a technical specification when the required support cannot b
30、e obtained for the publication of an International Standard, despite repeated efforts, or the subject is still under technical development or where, for any other reason, there is the future but no immediate possibility of an agreement on an International Standard. International Standard IEC 60871-3
31、, which is a technical specification, has been prepared by IEC technical committee 33: Power capacitors and their applications. This second edition cancels and replaces the first edition published in 1996. This edition constitutes a technical revision. PD IEC/TS 60871-3:2015 6 IEC TS 60871-3:2015 IE
32、C 2015 This edition includes the following significant technical changes with respect to the previous edition: a) Clearer writing of formulas on energy limitation for expulsion fuses; b) Updated normative references and bibliography; c) A new clause for synchronized switching has been added. The tex
33、t of this technical specification is based on the following documents: Enquiry draft Report on voting 33/545/DTS 33/563/RVC Full information on the voting for the approval of this technical specification can be found in the report on voting indicated in the above table. This publication has been dra
34、fted in accordance with the ISO/IEC Directives, Part 2. A list of all parts in the IEC 60871, published under the general title Shunt capacitors for a.c. power systems having a rated voltage above 1 000 V, can be found on the IEC website. The committee has decided that the contents of this publicati
35、on will remain unchanged until the stability date indicated on the IEC website under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication will be transformed into an International standard, reconfirmed, withdrawn, replaced by a revised edition, or am
36、ended. A bilingual version of this publication may be issued at a later date. PD IEC/TS 60871-3:2015IEC TS 60871-3:2015 IEC 2015 7 SHUNT CAPACITORS FOR AC POWER SYSTEMS HAVING A RATED VOLTAGE ABOVE 1 000 V Part 3: Protection of shunt capacitors and shunt capacitor banks 1 Scope This part of IEC 6087
37、1, 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. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispen
38、sable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60549, High-voltage fuses for the external protection of shunt capacitors IEC 60871-1, Shunt capacitors for a
39、.c. power systems having a rated voltage above 1 000 V Part 1: General IEC 60871-4, Shunt capacitors for AC power systems having a rated voltage above 1 000 V Part 4: Internal fuses 3 Terms and definitions For the purposes of this document, the terms and definitions given in IEC 60549, IEC 60871- 1
40、and IEC 60871-4 apply. 4 Internal fuses 4.1 General Internal fuses for shunt capacitors are selective current-limiting fuses arranged inside a capacitor. As defined in IEC 60871-4, they are designed to isolate faulted capacitor elements or capacitor unit, to allow operation of the remaining parts of
41、 that capacitor unit and the bank in which the capacitor unit is connected. The operation of an internal fuse is initiated by the breakdown of a capacitor element. The affected element is instantaneously disconnected by the operation of the element fuse without interruption in the operation of the c
42、apacitor. The number of externally parallel connected capacitors and the available short-circuit current of the supply system should not affect the current-limiting of internal fuses. It should be noted that internal fuses do not provide protection against a short circuit between internal connection
43、s or a short circuit between active parts and casing, both of which may lead to case rupture. PD IEC/TS 60871-3:2015 8 IEC TS 60871-3:2015 IEC 2015 4.2 Fuse characteristics 4.2.1 Rated current There is no definition or test method existing for element fuses. Element fuses are, in general, designed f
44、or much higher currents than the maximum permissible element current. They are meant to disconnect only faulty elements. The faulty elements and their fuses are not intended to be replaced. 4.2.2 Rated discharge capability IEC 60871-4 and IEC 60871-1 specify that the capacitor be subject to five und
45、amped discharges from a d.c. charge level of 2,5 U N . For special applications, where inrush currents and/or peak voltages are limited, lower discharge requirements are applicable. 4.2.3 Disconnecting capability Requirements and test procedures are given in IEC 60871-4. These tests verify that the
46、fuse has a current-limiting action. 4.2.4 Voltage withstand capability after operation Requirements and test procedures are given in IEC 60871-4. 4.3 Influence of capacitor element configuration on capacitor life 4.3.1 Capacitor with all elements connected in parallel After the breakdown of an eleme
47、nt, the respective fuse will melt in less than a millisecond owing to the discharge current from the parallel connected elements and capacitors and the power frequency current from the supply. The capacitor may, however, continue operating with a correspondingly reduced output. If the capacitor is o
48、perated at a fixed bus voltage, no variation in operating voltage on the remaining healthy elements will occur. 4.3.2 Capacitor with elements connected in series and parallel After the breakdown of an element, all parallel connected elements discharge their stored energy or part of it into the fault
49、y element. The power frequency current is limited by the remaining healthy elements connected in series. After the disconnection of the faulty element, the capacitor continues operating with a correspondingly reduced output. The remaining healthy elements of the group are then stressed with a voltage approximately m n /m (n 1) + 1 times the initial voltage, where n is the number of parallel connected elements per group and m the number of series- connected sections per unit. I
