Estimation of Restriking Transient Overvoltage on Disconnecting Switch for GIS

On an actual 550kV GIS (gas-insulated switchgear), the restriking surges of disconnecting switches at a high frequency of several MHz were successfully measured by employing two different methods. Further, by comparing the measured waveforms with waveforms obtained through calculations, it has been proved that restriking surge of disconnecting switches can be estimated by conducting calculations with considerably high accuracy. Also included, in this paper are certain suggestions regarding GIS simulation methods to be adopted for the calculations, while concurrently reported are the results of calculations on 111 circuit configurations at 10 different GIS's.