IEC 60076-18:2012

Power transformers - Part 18: Measurement of frequency response

IEC 60076-18:2012 covers the measurement technique and measuring equipment to be used when a frequency response measurement is required either on-site or in the factory either when the test object is new or at a later stage. This standard is applicable to power transformers, reactors, phase shifting transformers and similar equipment.

Transformateurs de puissance - Partie 18: Mesure de la réponse en fréquence

La CEI 60076-18:2012 couvre la technique de mesure et l'appareillage de mesure à utiliser lorsqu'une mesure de réponse en fréquence est requise, soit sur site, soit en usine, lorsque l'objet à soumettre à essai est neuf ou à un stade plus avancé. La présente norme est applicable aux transformateurs de puissance, bobines d'inductance, transformateurs déphaseurs et appareillages similaires.

General Information

• Status: Published
• Publication Date: 08-Jul-2012
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 29.060.20 - Cables
• ICS: 29.180 - Transformers. Reactors
• Technical Committee: TC 14 - Power transformers
• Drafting Committee: PT 60076-18 - TC 14/PT 60076-18
• Current Stage: PPUB - Publication issued
• Start Date: 15-Aug-2012
• Completion Date: 09-Jul-2012

Standards Content (Sample)

IEC 60076-18 ®
Edition 1.0 2012-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Power transformers –
Part 18: Measurement of frequency response

Transformateurs de puissance –
Partie 18: Mesure de la réponse en fréquence

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IEC 60076-18 ®
Edition 1.0 2012-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Power transformers –
Part 18: Measurement of frequency response

Transformateurs de puissance –

Partie 18: Mesure de la réponse en fréquence

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX X
ICS 29.180 ISBN 978-2-83220-222-7

– 2 – 60076-18 © IEC:2012
CONTENTS
FOREWORD . 5
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-check 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 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 Frequency 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 bandwidth . 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 measurements . 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

60076-18 © IEC:2012 – 3 –
Annex D (informative) Examples of measurement 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
Figure 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 – General 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 tertiary 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 response . 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 – Effect 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 winding 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.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 YNd1 transformer . 42

Table 1 – Standard measurements for a star connected winding with taps . 13
Table 2 – Standard measurements for delt
...