Recurrent Faults Identification in Medium Voltage Distribution System for Fault Early Warning

The subject addressed in this paper is identifying the recurrent faults from the recorded disturbance waveforms. The electrical equipment may experience self-clearing and instantaneous fault before the permanent faults occur, gradually reducing the insulation performance of the equipment. These faults are called incipient fault, which cannot be detected by the overcurrent relay for its low magnitude or short duration, but can occur many times before the permanent fault. At present, scholars have conducted related research of incipient faults. However, the causes of incipient fault may be different, it is difficult to apply these research methods to distribution fault early warning. Meanwhile, some incipient faults imply the high correlation and the same underlying causes. Such faults refer to recurrent faults . Therefore, recurrent faults identification should be finished before analyzing their cumulative effect on the permanent fault. Identification of these recurrent faults will facilitate distribution fault early warning and contributing to improving power supply reliability.