Location Method Based on Fuzzy Entropy for Single Phase to Ground Faults in Non-effectively Grounded Distribution Network

Single phase to ground faults in non-effectively grounded distribution network is difficult to locate accurately, because of weak fault current and noise influence. This paper proposes a location method based on the fuzzy entropy of transient zero-sequence current in the first capacitive frequency band. Firstly, the zero-sequence impedance characteristics are given, and the calculation method of the first capacitive frequency band is analyzed. Then, based on the simplified equivalent network, the difference between upstream and downstream transient zero-sequence current characteristics is summarized. Subsequently, the definition and calculation method of fuzzy entropy are given, and a location method by comparing the fuzzy entropy of transient zero-sequence currents is proposed. The method is applicable to both ungrounded and resonant grounded systems, and is capable of detecting high impedance faults. Finally, PSCAD simulation results verified the adaptability and effectiveness of proposed location method.