Switching Surge Test on No-Load 187-kV Transmission Line

Descriptions are given of measurements of switching surge generated by air blast breaker switching of charging current on no-load transmission line of the 187-kV effectively grounded system, with one-step insulation reduction, belonging to the Shikoku Electric Power Company, Japan. Measurements have been made on phase-to-ground surge overvoltages and phase-to-phase overvoltages at the sending end and receiving end, corresponding to various breaker operations, including high-speed reclosing. To examine the effect of system configuration upon switching surge, tests have been made on two system configurations. Maximum values of switching surge overvoltages which are likely to occur in the test system have been calculated by means of computer, and, making due reference to the measured results, insulation coordination has been examined.