Fault Analysis And Relay Protection Of Coal Mine Distribution Network

The safety in coal mine production has always been the top priority,and the equipment needed for coal mine production basically uses electricity as the source of power,so if the failure of coal mine distribution network can not be removed in time when coal mine distribution network breaks down,it is very likely to cause major safety accidents,such as gas explosions and so on.Coal mine distribution network has complex structure,changeable operation mode and severe working conditions,which not only increase the difficulty and workload of the setting of relay protection,but also increase the difficulty of fault line selection.Therefore,according to the characteristics of coal mine distribution network and aiming at designing an adaptive setting software for relay protection,this paper studies the fault line selection based on wavelet transform and neural network.In the aspect of relay protection setting,this paper designs the adaptive relay protection setting software based on Kingview.The software takes the relay protection devices of the distribution network in coal mine A,Huaibei Mining Group as the setting object,and calculates the setting value of the line relay protection devices online needed to be adjusted based on the established setting principle,according to the change of operation mode of distribution network,such as the change of distribution line length or load and so on.The functions of the software include drawing the main wiring diagram,inputting parameters,calculating the impedance under the maximum and minimum operation mode,calculating the short circuit current under the maximum and minimum operation mode,setting the line protection,checking the sensitivity and setting the transformer,etc.The software could adaptively set the operating current under the condition of ensuring the sensitivity.In the aspect of fault line selection,in order to improve the rapidity and reliability of the fault removal,according to the characteristics of transient zero sequence current in time domain and frequency domain when the fault occurs,this paper adopts the method of fault line selection based on wavelet transform and neural network.This method is mainly to decompose the fault zero sequence current obtained by the simulation of distribution network model into three-layer wavelet packet by using wavelet packet,calculate the wavelet packet coefficient on the third layer,and obtain the energy value representing the fault characteristics to train the Elman neural network.In the end,the method is verified by simulation by using MATLAB software in this paper,and the results show that the method can judge the fault circuit accurately.Figure [49] table [4] reference [52]...