Discrete Fréchet Distance Algorithm-Based Faulty Feeder Selection Method for Flexible Grounding System in Distribution Networks

Flexible grounding system is a new technology that applies power electronic equipment to grounding systems. The most typical characteristic is that when a single-phase ground fault occurs, it can inject a compensation current into the system through power electronic equipment to achieve arc extinguishing. However, when faced with a high-resistance ground fault, the flexible grounding system cannot accurately select the faulty feeder in the application of traditional faulty selection methods. A faulty feeder identification method combining the discrete Frechet Distance and wavelet packet transform is proposed in this paper to solve the problem. The wavelet packet transform is used to extract the characteristic quantity of the zero-sequence current when a single-phase ground fault occurs. Meanwhile, Frechet Distance is used to calculate the waveform similarity of the extracted characteristic curve. Finally, according to the likeness of each curve, the faulty feeder can be selected. The simulation results based on MATLAB/Simulink prove that this method can quickly and accurately choose faulty feeders.