EN 60076-18-2012 en Power transformers - Part 18 Measurement of frequency response.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationPart 18: Measurement of frequency responseBS EN 60076-18:2012Power transformersNational forewordThis British Standard is the UK implementation of EN 60076-18:2012. It isidentical

2、 to IEC 60076-18:2012.The UK participation in its preparation was entrusted to Technical CommitteePEL/14, Power transformers.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of a

3、contract. Users are responsible for its correct application. The British Standards Institution 2013Published by BSI Standards Limited 2013ISBN 978 0 580 69776 0ICS 29.180Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the auth

4、ority of the StandardsPolicy and Strategy Committee on BRITISH STANDARDBS EN 60076-18:2012Date Text affectedAmendments/corrigenda issued since publication31 January 2013.EUROPEAN STANDARD EN 60076-18 NORME EUROPENNE EUROPISCHE NORM September 2012 CENELEC European Committee for Electrotechnical Stand

5、ardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Management Centre: Avenue Marnix 17, B - 1000 Brussels 2012 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 60076-18:2012

6、E ICS 29.180 English version Power transformers - Part 18: Measurement of frequency response (IEC 60076-18:2012) Transformateurs de puissance - Partie 18: Mesure de la rponse en frquence (CEI 60076-18:2012) Leistungstransformatoren - Teil 18: Messung des Frequenzbertragungsverhaltens (IEC 60076-18:2

7、012) This European Standard was approved by CENELEC on 2012-08-13. 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 bibliograph

8、ical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre 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 responsib

9、ility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland,

10、Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. EN 60076-18:2012 - 2 - Foreword T

11、he text of document 14/718/FDIS, future edition 1 of IEC 60076-18, prepared by IEC/TC 14 “Power transformers“ was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as EN 60076-18:2012. The following dates are fixed: latest date by which the document has to be implemented at national

12、 level by publication of an identical national standard or by endorsement (dop) 2013-05-13 latest date by which the national standards conflicting with the document have to be withdrawn (dow) 2015-08-13 Attention is drawn to the possibility that some of the elements of this document may be the subje

13、ct of patent rights. CENELEC and/or CEN shall not be held responsible for identifying any or all such patent rights. Endorsement notice The text of the International Standard IEC 60076-18:2012 was approved by CENELEC as a European Standard without any modification. BS EN 60076-18:2012 2 60076-18 IEC

14、:2012 CONTENTS 1 Scope . 7 2 Terms and definitions . 7 3 Purpose of frequency response measurements 8 4 Measurement method . 9 4.1 General . 9 4.2 Condition of the test object during measurement . 10 4.3 Measurement connection and checks 11 4.3.1 Measurement connection and earthing 11 4.3.2 Zero-che

15、ck measurement 11 4.3.3 Repeatability check . 11 4.3.4 Instrument performance check . 11 4.4 Measurement configuration . 12 4.4.1 General . 12 4.4.2 Principles for choosing the measurement configuration . 12 4.4.3 Star- and auto-connected windings with a neutral terminal 13 4.4.4 Delta windings and

16、other windings without an accessible neutral . 13 4.4.5 Zig-zag connected windings. 14 4.4.6 Two-winding three-phase transformers 14 4.4.7 Three-phase auto-transformers . 14 4.4.8 Phase shifting transformers . 14 4.4.9 Reactors 14 4.4.10 Method for specifying additional measurements . 14 4.5 Frequen

17、cy range and measurement points for the measurement . 15 5 Measuring equipment . 15 5.1 Measuring instrument 15 5.1.1 Dynamic range 15 5.1.2 Amplitude measurement accuracy . 16 5.1.3 Phase measurement accuracy . 16 5.1.4 Frequency range . 16 5.1.5 Frequency accuracy 16 5.1.6 Measurement resolution b

18、andwidth 16 5.1.7 Operating temperature range . 16 5.1.8 Smoothing of recorded data . 16 5.1.9 Calibration . 16 5.2 Measurement leads . 16 5.3 Impedance 17 6 Measurement records . 17 6.1 Data to be recorded for each measurement . 17 6.2 Additional information to be recorded for each set of measureme

19、nts . 18 Annex A (normative) Measurement lead connections . 20 Annex B (informative) Frequency response and factors that influence the measurement 23 Annex C (informative) Applications of frequency response measurements . 37 BS EN 60076-18:201260076-18 IEC:2012 3 Annex D (informative) Examples of me

20、asurement configurations . 39 Annex E (informative) XML data format 43 Bibliography 44 Figure 1 Example schematic of the frequency response measurement circuit. 10 Figure A.1 Method 1 connection . 21 Figure A.2 Method 3 connection . 22 Figure B.1 Presentation of frequency response measurements 23 Fi

21、gure B.2 Comparison with a baseline measurement 24 Figure B.3 Comparison of the frequency responses of twin transformers . 24 Figure B.4 Comparison of the frequency responses from sister transformers . 25 Figure B.5 Comparison of the frequency responses of three phases of a winding. 25 Figure B.6 Ge

22、neral relationships between frequency response and transformer structure and measurement set-up for HV windings of large auto-transformer . 27 Figure B.7 Effect of tertiary delta connection on the frequency response of a series winding . 28 Figure B.8 Effect of star neutral connection on the tertiar

23、y winding response . 29 Figure B.9 Effect of star neutral termination on series winding response 29 Figure B.10 Measurement results showing the effect of differences between phases in internal leads connecting the tap winding and OLTC . 30 Figure B.11 Effect of measurement direction on frequency res

24、ponse . 30 Figure B.12 Effect of different types of insulating fluid on frequency response . 31 Figure B.13 Effect of oil filling on frequency response 31 Figure B.14 Effect of a DC injection test on the frequency response 32 Figure B.15 Effect of bushings on frequency response . 32 Figure B.16 Effe

25、ct of temperature on frequency response 33 Figure B.17 Examples of bad measurement practice 34 Figure B.18 Frequency response of a tap winding before and after partial axial collapse and localised inter-turn short-circuit with a photograph of the damage 34 Figure B.19 Frequency response of an LV win

26、ding before and after axial collapse due to clamping failure with a photograph of the damage 8 . 35 Figure B.20 Frequency response of a tap winding with conductor tilting with a photograph of the damage 1 . 36 Figure D.1 Winding diagram of an auto-transformer with a line-end tap changer 40 Figure D.

27、2 Connection diagram of an inductive inter-winding measurement on a three-phase YNd1 transformer 41 Figure D.3 Connection diagram for a capacitive inter-winding measurement on a three-phase YNd1 transformer 42 Figure D.4 Connection diagram for an end-to-end short-circuit measurement on a three-phase

28、 YNd1 transformer 42 Table 1 Standard measurements for a star connected winding with taps 13 Table 2 Standard measurements for delta connected winding without tap 14 Table 3 Format for specifying additional measurements . 15 Table D.1 Standard end-to-end measurements on a three-phase auto-transforme

29、r 39 Table D.2 Tap-changer connections . 40 BS EN 60076-18:2012 4 60076-18 IEC:2012 Table D.3 Inductive inter-winding measurements on a three-phase YNd1 transformer . 41 Table D.4 Capacitive inter-winding measurements on a three-phase YNd1 transformer . 41 Table D.5 End-to-end short-circuit measurem

30、ents on a three-phase YNd1 transformer . 42 BS EN 60076-18:201260076-18 IEC:2012 7 POWER TRANSFORMERS Part 18: Measurement of frequency response 1 Scope This part of the IEC 60076 series covers the measurement technique and measuring equipment to be used when a frequency response measurement is requ

31、ired either on-site or in the factory either when the test object is new or at a later stage. Interpretation of the result is not part of the normative text but some guidance is given in Annex B. This standard is applicable to power transformers, reactors, phase shifting transformers and similar equ

32、ipment. 2 Terms and definitions For the purposes of this document, the following terms and definitions apply. 2.1 frequency response amplitude ratio and phase difference between the voltages measured at two terminals of the test object over a range of frequencies when one of the terminals is excited

33、 by a voltage source Note 1 to entry: The frequency response measurement result is a series of amplitude ratios and phase differences at specific frequencies over a range of frequency. Note 2 to entry: The measured voltage is the voltage developed across an impedance and so it is also related to cur

34、rent. 2.2 frequency response analysis FRA technique used to detect damage by the use of frequency response measurements Note 1 to entry: The terms SFRA and IFRA are commonly used and refer to the use of either a swept frequency voltage source or an impulse voltage source. Provided the measuring equi

35、pment complies with the requirements of Clause 5, this standard can be applied to both techniques. 2.3 source lead lead connected to the voltage source of the measuring instrument used to supply an input voltage to the test object 2.4 reference lead Vinlead connected to the reference channel of the

36、measuring instrument used to measure the input voltage to the test object 2.5 response lead Voutlead connected to the response channel of the measuring instrument used to measure the output voltage of the test object BS EN 60076-18:2012 8 60076-18 IEC:2012 2.6 end-to-end measurement frequency respon

37、se measurement made on a single coil (phase winding) with the source and reference (Vin) leads connected to one end and the response (Vout) lead connected to the other end 2.7 apacitive inter-winding measurement frequency response measurement made on two adjacent coils (windings of the same phase) w

38、ith the source and reference (Vin) leads connected to one end of a winding, the response (Vout) lead connected to one end of another winding and with the other winding ends floating Note 1 to entry: This type of measurement is not applicable to windings which have common part or connection between t

39、hem. 2.8 inductive inter-winding measurement frequency response measurement made on two adjacent coils (windings of the same phase) with the source and reference (Vin) leads connected to one end of the higher voltage winding, the response (Vout) lead connected to one end of the other winding and wit

40、h the other ends of both windings grounded 2.9 end-to-end short circuit measurement frequency response measurement made on a single coil (phase winding) with the source and reference (Vin) leads connected to one end, the response (Vout) lead connected to the other end, and another winding of the sam

41、e phase short-circuited 2.10 baseline measurement frequency response measurement made on a test object to provide a basis for comparison with a future measurement on the same test object in the same configuration 3 Purpose of frequency response measurements Frequency response measurements are made s

42、o that Frequency Response Analysis (FRA) can be carried out. FRA can be used to detect changes to the active part of the test object (windings, leads and core). NOTE FRA is generally used to detect geometrical changes and electrical short-circuits in the windings, see Annex B. Some examples of condi

43、tions that FRA can be used to assess are: damage following a through fault or other high current event (including short-circuit testing), damage following a tap-changer fault, damage during transportation, and damage following a seismic event. Further information on the application of frequency resp

44、onse measurements is given in Annex C. The detection of damage using FRA is most effective when frequency response measurement data is available from the transformer when it is in a known good condition (baseline measurement), so it is preferable to carry out the measurement on all large transformer

45、s either in the factory or when the transformer is commissioned at site or both. If a baseline BS EN 60076-18:201260076-18 IEC:2012 9 measurement is not available for a particular transformer, reference results may be obtained from either a similar transformer or another phase of the same transforme

46、r (see Annex B). Frequency response measurements can also be used for power system modelling including transient overvoltage studies. 4 Measurement method 4.1 General To make a frequency response measurement, a low voltage signal is applied to one terminal of the test object with respect to the tank

47、. The voltage measured at this input terminal is used as the reference signal and a second voltage signal (the response signal) is measured at a second terminal with reference to the tank. The frequency response amplitude is the scalar ratio between the response signal (Vout) and the reference volta

48、ge (Vin) (presented in dB) as a function of the frequency. The phase of the frequency response is the phase difference between Vin and Vout(presented in degrees). The response voltage measurement is made across an impedance of 50 . Any coaxial lead connected between the test object terminal and the

49、voltage measuring instrument shall have a matched impedance. To make an accurate ratio measurement, the technical parameters of the reference and response channels of the measuring instrument and any measurement leads shall be identical. NOTE 1 The characteristic impedance of the coaxial measuring leads is chosen to match the measuring channel input impedance to minimise signal reflections and reduce the influence of the coaxial lead on the measurement to