The Research Of Fault Location Method Of Distribution Network

Higher demands have been advanced for power system reliability with the development of national economy and the improvement of people’s living standard. Improving the power supply reliability of distribution network is of great significance to improve the reliability of the power system as that the distribution network is attached to the user directly. This paper is committed to study the fault location method of short trouble because its destructibility is much bigger and its fault feature is more obvious.Firstly, improve the performance of matrix algorithm that is used to locate fault of distribution network as its fault tolerance is poor. Add the evaluation function to evaluate the split combinations of the fault location result of matrix algorithm and select the best split combination whose evaluation function value is the smallest of all the split combination as the fault section location result, which could improve the fault tolerance of matrix algorithm. Then the paper studies the fault section location method of distribution network based on immune algorithm and then compares the immune algorithm with genetic algorithm, the comparison results show that the immune algorithm choosing the next generation according to individual accessibility and the concentration can avoid the algorithm falling into local optimum fast.Then, the paper studies the fault location method of distribution network based on node impedance matrix. Firstly, forming the node impedance matrix of equivalent system before the fault, secondly, establishing the node impedance matrix of equivalent system with the adding virtual nodes after the fault, which contains the unknown fault distance, then modifying the transfer impedance between different nodes and the driving point impedance which contains the unknown fault distance and fault resistance according to branch adding method; secondly forming the fault point location expression according to the physical meaning of the node impedance matrix. At the same time, the paper proposes using static voltage characteristic load model to simulate the load. The simulation results indicate that the method is of great precision and has a certain ability to resist transition resistance.Finally, the paper analyzes the effect of DG to the fault section location scheme for the distribution network without DG and puts forward a way that limiting the capacity of DG accessed to the distribution network and setting reasonable values for switches, in which the fault information will be reported correctly and the fault section locating scheme for distribution network without DG is still suitable for distribution network containing DG, and then the paper researches the largest capacity of DG and feeder power longest distance, finally the paper putting forward the fault section location method for distribution network with DG when the capacity of DG exceeds the limit.