Travelling waves-based identification of sub-health condition of feeders in power distribution system
The majority of faults in power distribution system are caused by natural degradation of feeders. In addition, travelling waves will be generated during degradation of feeders. This study proposes a method based on travelling waves to identify sub-health condition, which represents the degradation of feeder before the feeder fails into a permanent fault. In the method, traveling waves in the power distribution system are monitored in real time. Then, the location of travelling wave source is determined by the polarity of travelling waves, which is extracted using wavelet transform. Finally, the degradation of feeder is identified when all the other possibilities to generate travelling waves are ruled out using the characteristics of power-frequency voltages and currents accompanied with travelling waves. Simulation results have verified that the proposed method is feasible and effective.