EN 60044-5:2004

STANDARDInstrumentni transformatorji – 5. del: Kapacitivni napetostnik (IEC 60044-5:2004)Instrument transformers - Part 5: Capacitor voltage transformers (IEC 60044-5 :2004)©
Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljenoReferenčna številkaSIST EN 60044-5:2005(en)ICS17.220.20

EUROPEAN STANDARD
EN 60044-5 NORME EUROPÉENNE EUROPÄISCHE NORM
June 2004 CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60044-5:2004 E
ICS 17.220.20 Supersedes HD 554 S1:1992
English version
Instrument transformers Part 5: Capacitor voltage transformers (IEC 60044-5:2004)
Transformateurs de mesure Partie 5: Transformateurs condensateurs de tension (CEI 60044-5:2004)
Messwandler Teil 5: Kapazitive Spannungswandler (IEC 60044-5:2004)
This European Standard was approved by CENELEC on 2004-06-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

Foreword The text of document 38/320/FDIS, future edition 1 of IEC 60044-5, prepared by IEC TC 38, Instrument transformers, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60044-5 on 2004-06-01. This European Standard, together with EN 60044-2:1999, supersedes HD 554 S1:1992. The following dates were fixed: – latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop) 2005-03-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow) 2007-06-01 Annex ZA has been added by CENELEC. __________ Endorsement notice The text of the International Standard IEC 60044-5:2004 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following note has to be added for the standard indicated:
IEC 60721 NOTE Harmonized in EN 60721 series (not modified). __________

- 3 - EN 60044-5:2004
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. NOTE Where an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60028 - 1) International standard of resistance for copper
- - IEC 60038 (mod) - 1) IEC standard voltages 2)
HD 472 S1 + corr. February 1989 3) 2002
IEC 60044-2 (mod) - 1) Instrument transformers Part 2: Inductive voltage transformers
EN 60044-2 1999 3) IEC 60050-321 - 1) International electrotechnical vocabulary - Chapter 321: Instrument transformers
- - IEC 60050-436 - 1) Chapter 436: Power capacitors
- - IEC 60050-601 - 1) Chapter 601: Generation, transmission and distribution of electricity - General
- - IEC 60050-604 - 1) Chapter 604: Generation, transmission and distribution of electricity - Operation
- - IEC 60060-1 - 1) High-voltage test techniques Part 1: General definitions and test requirements
HD 588.1 S1 1991 3) IEC 60071-1 - 1) Insulation co-ordination Part 1: Definitions, principles and rules
EN 60071-1 1995 3) IEC 60085 - 1) Thermal evaluation and classification of electrical insulation
HD 566 S1 1990 3) IEC 60270 - 1) High-voltage test techniques - Partial discharge measurements
EN 60270 2001 3) IEC 60358 - 1) Coupling capacitors and capacitor dividers
HD 597 S1 + corr. March 1992 3) 1992
1) Undated reference. 2) The title of HD 472 S1 is: Nominal voltages for low-voltage public electricity supply systems. 3) Valid edition at date of issue.

Publication Year Title EN/HD Year IEC 60481 - 1) Coupling devices for power line carrier systems
- - IEC 60815 - 1) Guide for the selection of insulators in respect of polluted conditions
- - IEC 62155 (mod) - 1) Hollow pressurized and unpressurized ceramic and glass insulators for use in electrical equipment with rated voltages greater than 1 000 V
EN 62155 2003 3) CISPR 18-2 - 1) Radio interference characteristics of overhead power lines and high-voltage equipment - Part 2: Methods of measurement and procedure for determining limits
- -
NORME INTERNATIONALECEIIEC INTERNATIONAL STANDARD 60044-5Première éditionFirst edition2004-04 Transformateurs de mesure – Partie 5: Transformateurs condensateurs de tension
Instrument transformers – Part 5: Capacitor voltage transformers Pour prix, voir catalogue en vigueur For price, see current catalogue IEC 2004
Droits de reproduction réservés
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Copyright - all rights reserved Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l'éditeur. 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 the publisher. International Electrotechnical Commission,
3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, SwitzerlandTelephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch
Web: www.iec.ch CODE PRIX PRICE CODE XB Commission Electrotechnique InternationaleInternational Electrotechnical CommissionМеждународнаяЭлектротехническаяКомиссия

60044-5  IEC:2004 – 3 –
CONTENTS FOREWORD.11
1 Scope.15 2 Normative references.15 3 Terms and definitions.17 3.1 General definitions.17 3.2 Capacitor voltage divider definitions.27 3.3 Electromagnetic unit definitions.33 3.4 Carrier-frequency accessories definitions.35 4 General requirements.35 5 Service conditions.35 5.1 Normal service conditions.35 5.2 Special service conditions.39 5.3 System earthing.41 6 Ratings.41 6.1 Standard values of rated frequency.41 6.2 Standard values of rated voltages.41 6.3 Standard values of rated output.43 6.4 Standard values of rated voltage factor.43 6.5 Limits of temperature rise.45 7 Design requirements.47 7.1 Insulation requirements.47 7.2 Other insulation requirements.51 7.3 Short-circuit withstand capability.57 7.4 Ferro-resonance.57 7.5 Electromagnetic emission requirements.59 7.6 Mechanical requirements.61 7.7 Tightness of capacitor voltage divider and electromagnetic unit.63 8 Classification of tests.63 8.1 Type tests.63 8.2 Routine tests.69 8.3 Special tests.69 8.4 Test sequence for one or two units.69 9 Type test.69 9.1 Temperature-rise test.69 9.2 Capacitance and tanδ measurement at power-frequency.73 9.3 Short-circuit withstand capability test.75 9.4 Impulse tests.77 9.5 Wet test for outdoor capacitor voltage transformer.79 9.6 Ferro-resonance tests.81 9.7 Tightness test of a liquid-filled electromagnetic unit.83 9.8 Accuracy tests.83 9.9 Transient response test.87 9.10 Radio interference voltage test.91

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10 Routine tests.91 10.1 Tightness of the liquid-filled capacitor voltage divider.91 10.2 Power-frequency withstand test and measurement of capacitance, tanδ and partial discharge.91 10.3 Verification of terminal markings.101 10.4 Power-frequency withstand tests on the electromagnetic unit.101 10.5 Ferro-resonance check.103 10.6 Accuracy check.103 11 Special tests.107 11.1 Measurement of the transmission factor of high frequency overvoltages.107 11.2 Mechanical strength test.107 11.3 Determination of the temperature coefficient (TC).109 11.4 Tightness design test of capacitor units.109 12 Marking of the capacitor units.109 12.1 General.109 12.2 Marking.109 13 Terminal markings.109 13.1 General.109 13.2 Markings.111 14 Additional requirements for measuring capacitor voltage transformer.111 14.1 Accuracy class designation.111 14.2 Standard reference range of frequency.111 14.3 Standard accuracy classes.113 14.4 Limits of voltage error and phase displacement.113 14.5 Tests for accuracy.115 15 Additional requirements for protective capacitor voltage transformers.115 15.1 Accuracy class designation.115 15.2 Standard reference range of frequency.115 15.3 Standard accuracy classes.115 15.4 Limits of voltage error and phase displacement.115 15.5 Transient response.117 15.6 Requirements for secondary windings intended to produce a residual voltage.119 16 Rating plate.123 16.1 Markings of the rating plate.123 16.2 Example of a typical rating plate.129 17 Requirements for carrier – frequency accessories.131 17.1 General.131 17.2 Drain coil and voltage limitation device.131 17.3 Type tests for carrier frequency accessories.133 17.4 Routine tests for carrier frequency accessories.133 17.5 Marking of the rating plate.135

60044-5  IEC:2004 – 7 –
Annex A (normative)
Typical diagram of a capacitor voltage transformer.137 Annex B (informative)
Transient response of capacitor
voltage transformer under fault conditions.139 Annex C (normative)
High-frequency characteristics of capacitor voltage transformers.141
Bibliography.143
Figure 1 – Altitude correction factor for the insulation.39 Figure 2 – Altitude correction factor for the temperature rise .45 Figure 3 – Flow charts test sequence to be applied when performing the type test (Figure 3a) and routine test (Figure 3b).67 Figure 4 – Diagram of a capacitor voltage transformer for the transient response test using equivalent circuit method.89 Figure 5 – Series burden.89 Figure 6 – Pure resistance.89 Figure 7 – Test circuit.97 Figure 8 – Alternative circuit.97 Figure 9 – Example of balanced test circuit.99 Figure 10 – Example of calibration circuit.99 Figure 11 – Example of an error diagram of class 1 CVT for accuracy check with the equivalent circuit.105 Figure 12 – Single-phase transformer with a neutral primary terminal and a single secondary.111 Figure 13 – Single-phase transformer with a neutral primary terminal and with two secondaries.111 Figure 14 – Single-phase transformer with a neutral primary terminal and with two tapped secondaries.111 Figure 15 – Single-phase transformer with a neutral primary terminal, with one residual voltage winding and a single secondary.111 Figure 16 – Error diagram of a capacitor voltage transformer for accuracy classes 0,2, 0,5 and 1,0.113 Figure 17 – Transient response of a capacitor voltage transformer.117 Figure A.1 – Example of a diagram for a capacitor voltage transformer.137 Figure A.2 – Example of a diagram for a capacitor voltage transformer with carrier-frequency accessories.137
Table 1 – Rated ambient temperature categories.37 Table 2 – Standard values of rated voltage factors for accuracy and thermal requirements.43 Table 3 – Limits of temperature rise of windings.47 Table 4 – Standard insulation levels.49 Table 5 – Partial discharge test voltages and permissible levels.53 Table 6 – Creepage distance.57

60044-5  IEC:2004 – 9 –
Table 7a – Ferro-resonance requirements.59 Table 7b – Ferro-resonance requirements.59 Table 8 – Transmitted overvoltage requirements.61 Table 9 – Static withstand test loads.61 Table 10 – Test voltage & burden for temperature rise test.73 Table 11 – Burden ranges for accuracy tests.85 Table 12 – Test voltages for units, stacks and complete capacitor voltage divider.93 Table 13 – Ferro resonance check.103 Table 14 – Accuracy check points (example).105 Table 15 – Modalities of application of the test loads to the line primary terminals.107 Table 16 – Limits of voltage error and phase displacement for measuring capacitor voltage transformers.113 Table 17 – Limits of voltage error and phase displacement
for protective capacitor voltage transformers.117 Table 18 – Standard values.119 Table 19 – Rated secondary voltages for capacitor voltage transformers to produce a residual voltage.121 Table 20 – Marking of the rating plate.123

60044-5  IEC:2004 – 11 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION ___________
INSTRUMENT TRANSFORMERS –
Part 5: Capacitor voltage transformers
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization 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 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 participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between 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 Publications 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 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 corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 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 National 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) Attention 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 shall not be held responsible for identifying any or all such patent rights. International Standard IEC 60044-5, has been prepared by IEC technical committee 38: Instrument transformers. This standard replaces IEC 60186 regarding capacitor voltage transformers as well as IEC-PAS 60044-5.

60044-5  IEC:2004 – 13 –
The text of this standard is based on the following documents: FDIS Report on voting 38/320/FDIS 38/324/RVD
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. This standard is Part 5 of IEC 60044, published under the general title Instrument transformers. This series consists of the following parts: IEC 60044-1:2003,
Instrument transformers – Part 1: Current transformers
IEC 60044-2:2003,
Instrument transformers – Part 2: Inductive voltage transformers IEC 60044-3:2002,
Instrument transformers – Part 3: Combined transformers
IEC 60044-5:2004
Instrument transformers – Part 5: Capacitor voltage transformers IEC 60044-6:1992,
Instrument transformers – Part 6: Requirements for protective current transformers for transient performance IEC 60044-7:1999,
Instrument transformers – Part 7: Electronic voltage transformers IEC 60044-8:2002,
Instrument transformers – Part 8: Electronic current transformers
The committee has decided that the contents of this publication will remain unchanged until 2007. At this date, the publication will be
• reconfirmed; • withdrawn; • replaced by a revised edition, or • amended.

60044-5  IEC:2004 – 15 –
INSTRUMENT TRANSFORMERS –
Part 5: Capacitor voltage transformers
1 Scope This part of IEC 60044 applies to new single-phase capacitor voltage transformers connected between line and ground for system voltages Um ≥ 72,5 kV at power frequencies from 15 Hz to 100 Hz. They are intended to supply a low voltage for measurement, control and protective functions.
The capacitor voltage transformer can be equipped with or without carrier-frequency accessories for power line carrier-frequency (PLC) application at carrier frequencies from
30 kHz to 500 kHz. This standard replaces IEC 60186 regarding capacitor voltage transformers. Three standards formed the basis for this IEC 60044-5 standard: − IEC 60044-2, concerning inductive voltage transformers;
− IEC 60358, concerning coupling capacitors and capacitor dividers; − IEC 60481, concerning coupling devices for power line carrier (PLC) systems. The measurement application includes both indication measuring and revenue measuring. NOTE Diagrams of capacitor voltage transformer to which this standard applies are given in Figures A.1 and A.2. 2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60028, International standard of resistance for copper IEC 60038, IEC standard voltages IEC 60044-2, Instrument transformers – Part 2: Inductive voltage transformers IEC 60050-321:1986, International Electrotechnical Vocabulary (IEV) – Chapter 321: Instrument transformers IEC 60050-436:1990, International Electrotechnical Vocabulary (IEV) – Chapter 436: Power capacitors IEC 60050-601:1985, International Electrotechnical Vocabulary (IEV) – Chapter 601: Generation, transmission and distribution of electricity – General

60044-5  IEC:2004 – 17 –
IEC 60050-604:1987, International Electrotechnical Vocabulary (IEV) – Chapter 604: Generation, transmission and distribution of electricity – Operation
IEC 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements IEC 60071-1, Insulation co-ordination – Part 1: Definitions, principles and rules IEC 60085, Thermal evaluation and classification of electrical insulation IEC 60270, High-voltage test techniques – Partial discharge measurements IEC 60358:1990, Coupling capacitors and capacitor dividers IEC 60481, Coupling devices for power line carrier systems IEC 60815, Guide for the selection of insulators in respect of polluted conditions IEC 62155, Hollow pressurized and unpressurized ceramic and glass insulators for use in electrical equipment with rated voltages greater than 1 000 V
CISPR 18-2, Radio interference characteristics of overhead power lines and high-voltage equipment – Part 2: Methods of measurement and procedure for determining limits 3 Terms and definitions For the purposes of this document, the following definitions apply.
NOTE Some of these definitions are identical with or are similar to those of IEC 60050-321, IEC 60050-436, IEC 60050-601 and IEC 60050-604. These are indicated by the relevant IEV reference number in brackets. 3.1 General definitions 3.1.1 capacitor voltage transformer
CVT a voltage transformer comprising a capacitor divider unit and an electromagnetic unit so designed and interconnected that the secondary voltage of the electromagnetic unit is substantially proportional to the primary voltage, and differs in phase from it by an angle which is approximately zero for an appropriate direction of the connections
[IEV 321-03-14] 3.1.2 rated frequency of a capacitor voltage transformer
fR the frequency for which the capacitor voltage transformer has been designed 3.1.3 standard reference range of frequency the range of frequency for which the rated accuracy is applicable

60044-5  IEC:2004 – 19 –
3.1.4 rated primary voltage
UPR the value of the primary voltage which appears in the designation of the capacitor voltage transformer and on which its performance is based
[IEV 321-01-12] 3.1.5 rated secondary voltage
USR the value of the secondary voltage which appears in the designation of the capacitor voltage transformer and on which its performance is based
[IEV 321-01-16] 3.1.6 secondary winding the winding which supplies the voltage circuits of measuring instruments, meters, protective or control devices [IEV 321-01-07] 3.1.7 secondary circuit the external circuit supplied by the secondary winding of a transformer 3.1.8 actual transformation ratio of a voltage transformer the ratio of the actual primary voltage to the actual secondary voltage of a voltage transformer [IEV 321-01-18] 3.1.9 rated transformation ratio of a voltage transformer KR the ratio of the rated primary voltage to the rated secondary voltage of a voltage transformer [IEV 321-01-20] 3.1.10
voltage error (ratio error)
εεεεu the error which a voltage transformer introduces into the measurement of a voltage and which arises from the fact that the actual transformation ratio is not equal to the rated transformation ratio
[IEV 321-01-22] NOTE This definition for steady state conditions is only related to components at rated frequency of both primary and secondary voltages, and does not take into account direct voltage components and residual voltages. voltage error (%)
PP SRUUUUKε−=
60044-5  IEC:2004 – 21 –
where KR
is the rated transformation ratio, UP
is the actual primary voltage, and Us
is the actual secondary voltage when UP is applied under the conditions of measurement. 3.1.11 phase displacement
ϕϕϕϕU the difference in phase between the primary and the secondary voltage phasors: ϕU=(ϕS − ϕP) the direction of the phasors being so chosen that the angle (ϕU) is zero for a perfect transformer.
NOTE 1 The phase displacement is said to be positive when the secondary voltage phasor (ϕS) leads the primary voltage phasor (ϕP). It is usually expressed in minutes or centiradians.
[IEV 321-01-23 modified] NOTE 2 This definition is strictly correct for sinusoidal voltages only. 3.1.12 accuracy class designation assigned to a capacitor voltage transformer, the errors of which remain within specified limits under prescribed conditions of use 3.1.13 burden admittance of the secondary circuit expressed in siemens and with an indication of the power factor (lagging or leading) NOTE The burden is usually expressed as the apparent power in volt-amperes, absorbed at a specified power factor and at the rated secondary voltage. 3.1.14 rated burden value of the burden on which the accuracy requirements of this standard are based 3.1.15 output a)
rated output the value of the apparent power (in volt-amperes at a specified power factor), which the capacitor voltage transformer is intended to supply to the secondary circuit at the rated secondary voltage and with rated burden connected to it
[IEV 321-01-27 modified] b)
thermal limiting output the value of the apparent power in volt-amperes referred to rated voltage which can be taken from a secondary winding, at rated primary voltage applied, without exceeding the limits of temperature rise of 6.5 NOTE 1 In this condition the limits of error may be exceeded. NOTE 2 In the case of more than one secondary winding, the thermal limiting output is to be given separately for each winding. NOTE 3 The simultaneous use of more than one secondary winding is not permitted unless there is an agreement between the manufacturer and purchaser.

60044-5  IEC:2004 – 23 –
3.1.16 highest voltage for equipment
Um the highest r.m.s. value of phase-to-phase voltage for which the equipment is designed and may be used in respect of its insulation 3.1.17 rated insulation level the combination of voltage values which characterises the insulation of a transformer with regard to its capability to withstand dielectric stresses 3.1.18 isolated neutral system a system where the neutral point is not intentionally connected to earth, except for high impedance connections for protection or measurement purposes
[IEV 601-02-24] 3.1.19 solidly earthed (neutral) system a system whose neutral point(s) is (are) earthed directly
[IEV 601-02-25] 3.1.20 impedance earthed (neutral) system a system whose neutral point(s) is (are) earthed through impedances to limit earth fault currents [IEV 601-02-26] 3.1.21 resonant earthed (neutral) system a system in which one or more neutral points are connected to earth through reactances which approximately compensate the capacitive component of a single-phase-to-earth fault current [IEV 601-02-27] NOTE With resonant earthing of a system, the residual current in the fault is limited to such an extent that an arcing fault in air is self-extinguishing. 3.1.22 earth fault factor at a given location of a three-phase system, and for a given system configuration, the ratio of the highest r.m.s. phase-to-earth power frequency voltage on a healthy phase during a fault to earth affecting one or more phases at any point on the system to the r.m.s. value of phase-to-earth power frequency voltage which would be obtained at the given location in the absence of any such fault
[IEV 604-03-06] 3.1.23 earthed neutral system system in which the neutral is connected to earth either solidly or through a resistance or reactance of sufficiently low value to reduce transient oscillations and to give a current sufficient for selective earth fault protection

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a) A three-phase system with effectively earthed neutral at a given location is a system characterized by an earth fault factor at this point which does not exceed 1,4. NOTE This condition is obtained approximately when, for all system configurations, the ratio of zero-sequence reactance to the positive-sequence reactance is less than 3 and the ratio of zero-sequence resistance to positive-sequence reactance is less than one. b) A three-phase system with non-effectively earthed neutral at a given location is a system characterized by an earth fault factor at this point that may exceed 1,4. 3.1.24 exposed installation an installation in which the apparatus is subject to overvoltages of atmospheric origin NOTE Such installations are usually connected to overhead transmission lines either directly or through a short length of cable. 3.1.25 non-exposed installation an installation in which the apparatus is not subject to overvoltages of atmospheric origin NOTE Such installations are usually connected to underground cable networks. 3.1.26 measuring capacitor voltage transformer a capacitor voltage transformer intended to supply indicating instruments, integrating meters and similar apparatus 3.1.27 protective capacitor voltage transformer a capacitor voltage transformer intended to provide a supply to electrical protective relays 3.1.28 residual voltage winding the winding of a single-phase capacitor voltage transformer intended, in a set of three single-phase transformers, for connection in broken delta for the purpose of producing a residual voltage under earth-fault conditions 3.1.29 rated voltage factor
FV the multiplying factor to be applied to the rated primary voltage UPR to determine the maximum voltage at which a transformer must comply with relevant thermal requirements for a specified time and with the relevant accuracy requirements 3.1.30 rated temperature category of a capacitor voltage transformer the range of temperature of the ambient air or of the cooling medium for which the capacitor voltage transformer has been designed 3.1.31 line terminal terminal intended for connection to a line conductor of a network
[IEV 436-03-01]
60044-5  IEC:2004 – 27 –
3.1.32 ferro-resonance sustained resonance of a circuit consisting of a capacitance with a non-linear saturable magnetic inductance NOTE The ferro-resonance can be initiated by switching operations on the primary side or secondary side. 3.1.33 transient response the measured fidelity of the secondary-voltage waveform, compared with the voltage waveform at the high-voltage terminal under transient conditions 3.1.34 mechanical stress the stresses on different parts of the capacitor voltage transformer as a function of four main forces:
− forces on the terminals due to the line connections, − forces due to the wind on the cross-section of the capacitor voltage transformer with and without line trap mounted on the top of the coupling capacitor, − seismic forces and − electrodynamic forces due to short circuit current 3.1.35 voltage-connected CVT CVT which has only one connection to the high voltage line NOTE Under normal conditions the top connection carries only the current of the capacitor voltage transformer. 3.1.36 current-connected CVT CVT which has two connections to the high voltage line NOTE The terminals and the top connection are designed to carry the line current under normal conditions. 3.1.37 line trap-connected CVT CVT which supports a line trap on its top NOTE 1 In this case, the two connections to the line trap carry the HV line current and one connection from the line trap to the CVT carries the CVT current NOTE 2 The pedestal-mounting line traps in two phases generate additional forces during a short circuit in more than one phase. 3.2 Capacitor voltage divider definitions 3.2.1 capacitor voltage divider a capacitor stack forming an alternating voltage divider
[IEV 436-02-10] 3.2.2 (capacitor) element a device consisting essentially of two electrodes separated by a dielectric
[IEV 436-01-03]
60044-5  IEC:2004 – 29 –
3.2.3 (capacitor) unit an assembly of one or more capacitor elements in the same container with terminals brought out
[IEV 436-01-04] NOTE A common type of unit for coupling capacitors has a cylindrical housing of insulating material and metallic flanges which serve as terminals. 3.2.4 (capacitor) stack an assembly of capacitor units connected in series [IEV 436-01-05] NOTE The capacitor units are usually mounted in a vertical array. 3.2.5 capacitor a general term used when it is not necessary to state whether reference is made to a capacitor unit or to a capacitor stack 3.2.6 rated capacitance of a capacitor
CR the capacitance value for which the capacitor has been designed NOTE This definition applies: • for a capacitor unit, to the capacitance between the terminals of the unit; • for a capacitor stack, to the capacitance between line and low voltage terminals or between line and earth terminals of the stack; • for a capacitor divider, to the resultant capacitance: CR =C1C2/(C1 + C2). 3.2.7 coupling capacitor a capacitor used for the transmission of signals in a power system
[IEV 436-02-11] 3.2.8 high voltage capacitor (of a capacitor divider)
C1 the capacitor connected between the line terminal and the intermediate voltage terminal of a capacitor divider
[IEV 436-02-12 modified] 3.2.9 intermediate voltage capacitor (of a capacitor divider)
C2 the capacitor connected between the intermediate voltage and the low voltage terminals of a capacitor divider [IEV 436-02-13]

60044-5  IEC:2004 – 31 –
3.2.10 intermediate voltage terminal (of a capacitor divider) a terminal intended for connection to an intermediate circuit such as the electromagnetic unit of a capacitor voltage transformer
[IEV 436-03-03] 3.2.11 low voltage terminal of a capacitor divider a terminal (N) intended for connection to earth either directly or via a drain coil of negligible value of impedance, at rated frequency, for power line carrier (PLC) application [IEV 436-03-04, modified] 3.2.12 capacitance tolerance the permissible difference between the actual capacitance and the rated capacitance under specified conditions
[IEV 436-04-01] 3.2.13 equivalent series resistance of a capacitor virtual resistance which, if connected in series with an ideal capacitor of capacitance value equal to that of the capacitor in question, would have a power loss equal to the active power dissipated in that capacitor under specified operating conditions at a given high frequency 3.2.14 high frequency capacitance (of a capacitor) the effective capacitance at a given frequency resulting from the joint effect of the intrinsic capacitance and the self-inductance of the capacitor
[IEV 436-04-03] 3.2.15 intermediate voltage of a capacitor divider
UC the voltage between the intermediate voltage terminal of the capacitor divider and the low voltage terminal, when the primary voltage is applied between the high and low voltage terminals or high voltage terminal and earth terminal 3.2.16 voltage ratio (of a capacitor divider) KCR the ratio of the voltage applied to the capacitor divider to the open-circuit intermediate voltage [IEV 436-04-05] NOTE 1 This ratio corresponds to the sum of the capacitances of the high voltage and intermediate voltage capacitors divided by the capacitance of the high voltage capacitor: (C1 + C2) / C1 = KCR. NOTE
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