Positioning of medium-pressure distribution network segment based on zero sequence current sudden change

摘要

Medium-voltage power distribution network mostly adopts neutral point small-current grounding in China. Currently in the medium voltage distribution network small current grounding system, the sector positioning problem of single-phase earth faults of such systems has not been satisfactorily solved.In this paper, a typical medium voltage distribution network model is established in PSCAD. The transient currents on both sides of the fault point are analyzed after EMD decomposition when the fault occurs, and the first layer intrinsic modal function is taken as the Hilbert transform. After the Hilbert transform.it's found that Before the fault point, the magnitude of the zero-sequence current amplitude is positive, and the magnitude of the current amplitude after the fault point is negative. According to this feature, a criterion can be constructed to determine the location of the faulty segment. The simulation results verify the correctness of the proposed segment location method. the new single-phase ground fault region is proposed Segment positioning method. The principle of the method is simple and easy to understand, requires less data, and is conducive to hardware implementation.