The Capability of 500kV Circuit Breaker for Interruption of Short Circuit Current with a Large D.C. Component

Abstract

The time constants of the D.C. component of asymmetrical fault current are trend to increase. It is said that interruption capability of gas circuit breaker degrades at asymmetrical current interruption.
This paper shows the investigation of the interruption capability of 550kV one-break SF₆ gas circuit breaker at asymmetrical current interruption. Interrupting tests of asymmetrical current with time constant 100ms, 150ms were carried out in high power laboratory. At the interrupting tests, arcing time was changed due to the time constant of the D.C. component. From the interrupting test results, arc energy was calculated. Degradation of the interrupting capability at asymmetrical current interruption was investigated by using measured arc energy.