Post-arc current reconstruction based on actual circuit breaker measurements

During short line fault (SLF) tests on three poles of a 72.5 kV, 31.5 kA, 60 Hz SF₆ puffer circuit breaker, some remarkably large post-arc currents were measured. For all the measurements performed on the three poles of the specific breaker, no physical post-arc currents could be detected in the measurement data, except for two cases. Both ´post-arc currents´ occurred as a last successful interruption of a circuit breaker pole. After these specific interruptions, the circuit breaker poles were degraded so much that only reignitions occurred. In order to verify the observed ´post-arc currents´, computations are made based on the more accurate voltage measurements