CIGRE Report(Working Group A3.06)

Ú·²¿´ λ°±®¬ ±º ¬¸» îððì ó îððé ײ¬»®²¿¬·±²¿´ Û²¯«·®§ ±² λ´·¿¾·´·¬§ ±º Ø·¹¸ ʱ´¬¿¹» Û¯«·°³»²¬ ﮬ ì ó ײ­¬®«³»²¬ Ì®¿²­º±®³»®­

ɱ®µ·²¹ Ù®±«° ßíòðê

ѽ¬±¾»® îðïî

Working Group A3.06

Final Report of the 2004 - 2007 International Enquiry on Reliability of High Voltage Equipment

Part 4 - Instrument Transformers

Members M. Runde (NO) Convener, C. E. Sölver (SE) Past Convener, A. Carvalho (BR), M. L. Cormenzana (ES), H. Furuta (JP), W. Grieshaber (FR), A. Hyrczak (PL), D. Kopejtkova (CZ), J. G. Krone (NL), M. Kudoke (CH), D. Makareinis (DE), J. F. Martins (PT), K. Mestrovic (HR), I. Ohno (JP), J. Östlund (SE), K.-Y. Park (KR), J. Patel (IN), C. Protze (DE), J. Schmid (DE), J. E. Skog (US), B. Sweeney (UK), F. Waite (UK).

Corresponding Members B. Bergman (CA), S. Tsukao (JP)

Copyright © 2012 “Ownership of a CIGRE publication, whether in paper form or on electronic support only infers right of use for personal purposes. Are prohibited, except if explicitly agreed by CIGRE, total or partial reproduction of the publication for use other than personal and transfer to a third party; hence circulation on any intranet or other company network is forbidden”.

Disclaimer Notice “CIGRE gives no warranty or assurance about the contents of this publication, nor does it accept any responsibility, as to the accuracy or exhaustiveness of the information. All implied warranties and conditions are excluded to the maximum extent permitted by law”.

ISBN: 978- 2- 85873- 205-0

Findings and Commentary Current transformers form the majority of the survey with around 64% of the service experience. Voltage transformers form around 30% of the service experience, split roughly equally between capacitor and magnetic designs. Combined current and voltage transformers form a much smaller part of the survey. Compared with the previous second survey there is a significant drop in the number of combined current and voltage transformers reported.

4.5.4

CT Arrangement of AIS CT Service Experience Distribution

The respondents were asked to divide their current transformer population into the arrangement or design of the current transformer. The eyebolt arrangement was assumed to be similar to the hairpin arrangement and both are included together. This question only has a valid choice for AIS current transformers and combined instrument transformers. The results for combined instrument transformers are shown in Table 4-18. Since over 87% of the population was either bar primary or other / unknown and the residual population was so small no further analysis was performed on the CT arrangement of combined instrument transformers (indeed some of the CT arrangements for combined instrument transformers were though technically unlikely to be used and may have been entered in error). The results for current transformers are shown in Table 4-19 and Table 4-20 and graphically in Figure 4-12 and Figure 4-13. Table 4-18: AIS CCVT arrangement service experience (all countries)

Voltage class 60 U