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.