Very high frequency overvoltages at open air EHV substations during disconnect switch operations

Author

Rashkes, V.S. ; Ziles, L.D.

Author_Institution

239 South St., Pittsfield, MA, USA

Volume

11

Issue

3

fYear

1996

fDate

7/1/1996 12:00:00 AM

Firstpage

1618

Lastpage

1623

Abstract

EHV open air substations experience flashovers produced by very high frequency overvoltages (VHF OV) during disconnect switch operations. It was found, during field tests, that the highest measured value of sparkover voltage across the EHV switch gap between contacts during its operation was 1.9 p.u. The most unfavourable scheme, theoretically, occurs when a bus is fed from a single transformer, without outgoing lines. Calculations showed that in 787 and 525 kV substations with branched buses, VHF OV could result in flashovers on a bus open end with unfavourable ratio of bus lengths. For transformer insulation protected with an arrester, VHF OV are not dangerous. Some protective measures are recommended

Keywords

flashover; overvoltage; power system measurement; power system protection; power system transients; power transformer protection; power transformers; sparks; transformer substations; 525 kV; 787 kV; EHV switch gap; VHF overvoltages; disconnect switch operations; field tests; flashovers; open air EHV substations; protective measures; sparkover voltage; transformer; Arresters; Contacts; Flashover; Frequency; Power transformer insulation; Substations; Surges; Switches; Testing; Voltage;

fLanguage

English

Journal_Title

Power Delivery, IEEE Transactions on

Publisher

ieee

ISSN

0885-8977

Type

jour

DOI

10.1109/61.517525

Filename

517525