| With the proportion of power cable in urban areas power grids increasing quickly, resulting in the distribution network distributed capacitance and conductance increase quickly, ground capacitive current of distribution network is increasing gradually, so that fault current increases when single-phase ground fault occurs, the compensating method of neutral point grounding through Arc-Suppression Coil is commonly used in our country. The paper analyzes some methods have been proposed for fault line detection and location of distribution systems, considering the new features, a Neutral point grounding via Arc-Suppression Coil of multi-branch simulation model was constructed with MATLAB/simulink tool, which have cable lines, overhead lines and cable-overhead lines.A large number of simulation experiments conducted based on multi-branch network simulation model. The characteristics of the cable in distribution network, the compensation characteristics of arc suppression coil, traveling wave of electromagnetic coupling characteristics, and different fault closing angles and transition resistances affect fault traveling wave have been discussed. Laid the foundation for the methods of fault line selection and location have been proposed. The mathematical morphology Top-Bottom detection method is applicable not only zero sequence current line selection but also A, C two-phase current to achieve the correct alignment.In the realization of fault line selection, based on the fault line, in order to faster troubleshooting need to determine the exact fault location, based on the the relationship between signal spectrum and fault location the use of S-transform through the neural network method for fault location is proposed. The paper also analyzes the fault location and fault lines wave the corresponding relationship, and on this basis proposed a fault location method by the first wave of Lipischitz indexβand the first three waves tip difference. |
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