Faulty Feeder Detection for Single Line-to-Ground Fault in Distribution Networks With DGs Based on Correlation Analysis and Harmonics Energy

Faulty feeder detection helps ensure the stable operation after single line-to-ground (SLG) faults in distribution networks. However, the SLG fault currents are weak, the fault conditions are complex, and distortion of fault signals may occur owing to the effect of distributed generators (DGs), which would result in unacceptable performance of the existing detection methods. To improve the accuracy of faulty feeder detection under high penetration of DGs, this paper firstly analyzes the three-sequence networks after SLG faults occur in distribution networks with DGs connection, and points out that the DGs connection does affect the zero-sequence components when DGs are connected to the faulty feeder. Besides, the polarity differences between zero-sequence voltage (ZSV) and zero-sequence currents (ZSC) are revealed. Subsequently, variational mode decomposition is employed to characterize the overall trend of the ZSV and ZSCs, and cross-correlation analysis is applied to capture the polarity characteristics between ZSV and ZSCs. In addition, harmonics characteristics of ZSCs are used as an auxiliary criterion when ZSCs are highly distorted caused by DGs connection. Finally, both of them are utilized to construct the detection scheme. Simulation results and practical data test demonstrate the efficiency of the proposed method.