Study On Fault Line Selection In Medium Voltage Distribution Network

With the rapid development of our economy, to improve the level of industrialization, significantly enhance the rapid advance of urbanization and people’s living standards, the majority of electricity customers on power supply reliability of the increasingly high demand. Which has an important influence on operation of different grounding modes on the electric power system, lOkV distribution network grounding mode selection is an important link in the development process of distribution system. At the same time, the distribution network faults for the entire power grid will bring great influence to the distribution network fault line selection becomes particularly important. This paper is based on these two questions to study.First analyzes the development of neutral grounding mode and the advantages and disadvantages of some power system, and the technical characteristics of three kinds of distribution network neutral grounding mode and the current needs to be improved is discussed, and three kinds of situation to do a detailed analysis and comparison; and the factors influencing the neutral way choice to do the analysis from two aspects respectively; the steady state and transient analysis shows that the system is in different neutral grounding mode, typical faults, variation of voltage and current; according to the topology of lOkV distribution network communication system, a simulation model of lOkV distribution network to establish the corresponding electromagnetic transient simulation software PSCAD/EMTDC based on the in the PSCAD electromagnetic transient simulation, respectively set up three neutral grounding mode, verify the characteristics of the current voltage, and draws a conclusion:the small resistance The operation mode has certain superiority in the 10kV distribution network.At the end of this paper, we study the problem of fault line selection in 10kV distribution network, and put forward a new method of fault line selection, aiming at the shortcomings of various existing fault line selection methods. The method firstly zero sequence current of wavelet entropy variation characteristics, obtain the arrival time of traveling wave, then by using EMD decomposition method corresponding to the zero sequence current decomposition, for first-order difference value by the high-frequency components of the IMF, according to the characteristics of the results to judge and determine the fault position, the final completion of fault line selection. In this paper, the method is proved to be correct and effective by PSCAD/EMTDC and MATLAB, which can identify the fault line and realize the function of fault line selection.