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.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
