| In 35 kv and 10 kv medium voltage power distribution system generally adopts the small current grounding method, By the statistics, caused by single phase grounding line failure rate as high as 80%.Due to the single-phase earth fault of fault current is small, the fault feature extraction difficulty, the influence of such factors as single-phase earth fault line selection problem has not a good solution.Therefore, how to timely find out the fault lines, remove line fault, to ensure the continuity and reliability of the power supply, the important technical and economic significance.Our common way of small current grounding neutral point grounding system, the neutral point through the arc suppression coil grounding system and the neutral point through high resistance grounded system.We studied and analyzed the fault feature information of the small current grounding system, the grounding system and the arc suppression coil grounding two way MATLAB simulation model is established, it is concluded that a variety of situations of voltage and current waveform diagram, finally through comparing the simulation results and theoretical study, we established is proved the correctness of the model of distribution network.As a result of the existing single criterion of grounding fault line selection method has certain shortcomings and limitations, make the line selection accuracy rate is very low.By using the method of fuzzy comprehensive decision, will be a variety of line selection criterion with complementary advantages for information fusion, form a composite line selection method of multiple criteria.Through the MATLAB simulation experiment based on the results of fuzzy comprehensive decision compared with three methods, show that fuzzy comprehensive decision can fast and accurate selecting fault line,line selection effect is very good.And confirm the correctness and reliability of the method,to verify the feasibility of built system. |
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