Research On Intelligent Guarantee Technology Of High-voltage Safety Power Supply System In Coal Mine

In recent years,with the development of coal industry,the level of mechanization and automation of coal mine is constantly improving.In order to ensure safe and efficient production,higher requirements are put forward for safe power supply system for coal mine.However,the capacity expansion of the high-voltage power grid of coal mine makes the power supply structure becoming more and more complex,and the ability of fault withstand getting weaker and weaker.No matter what kind of electrical fault occurs in underground high-voltage power supply grid,it will seriously affect the reliability and safety of power supply in coal mine,resulting in power failure,shutdown and even major safety accidents.Therefore,it has important theoretical value and practical significance to carry out the research on intelligent guarantee technology of high-voltage safety power supply system for coal mine.So,this paper carries out the research on intelligent guarantee technology of high-voltage safety power supply system for coal mine,focusing on solving the technical problems in intelligent fault protection,such as intelligent setting calculation of over-current protection,leakage current line selection,cable insulation monitoring,etc.To solve the technical problems of low efficiency and poor adaptability in the setting and calculation of the high-voltage power grid in coal mine,the existing topology analysis method of the high-voltage power grid in coal mine is improved,the concept of node coincidence is introduced,and the adaptive topology analysis method of the high-voltage power grid in coal mine based on node coincidence and incidence matrix is proposed,which can identity the actual topology identification of the high-voltage power grid in coal mine.This method is accurate,simple and efficient.Therefore,we can construct an effective topology analysis model for the subsequent short-circuit calculation and setting calculation.Based on the particle swarm optimization algorithm,a parallel computing scheduling strategy is put forword.Through the steps of grouping the power supply system diagram of coal mine and parallel computing of particle swarm optimization,the adaptive parallel topological analysis for high-voltage power grid can be realized.So,we can complete the parallel automatic short circuit calculation and setting calculation under various tolerant modes.This method has the advantages of high accuracy,fast calculating speed and lower execution time.An on-line management method of multi-mode fixed value scheme is proposed based on TCPN(Time Colored Petri-net).After periodic having the state of the high-voltage switchs,we can judge the changing situation of the power supply system.Based on this,the adaptive adjustment for the fixed value scheme can be completed and the on-line intelligent management of the coal mine high-voltage power supply system can be realized.An intelligent system of multimode setting calculation for high-voltage power grid of coal mine is developed based on Visual C++,which can complete automatic drawing of high-voltage power supply system diagram,network topology self-learning,system status online collection,automatic parallel short circuit calculation and online setting calculation.The actual application in Xin'an coal mine of Henan Dayou Energy Co.,Ltd shows that the setting calculation is accurate,practical and high efficiency,strong adaptability.To solve the power technical problems of poor effect in the line selection of leakage protection of the high-voltage power grid in coal mine,a new method of line selection leakage protection in mine high-voltage power grid based on Prony and mutual approximate entropy method is proposed.Based on a systematic study of the mechanism and transient characteristics of the leakage fault,use the zero sequence voltage off-limit and zero sequence voltage break variable off-limit to judge whether the leakage fault occurs.Utilizing the transient main frequency component waveform of the perfect line after the fault is similar,and the fault line and the perfect line have obvious differences features.The Prony algorithm is used to extract the transient main frequency component of the zero sequence current of each line.Calculating the mutual approximate entropy value by pairwise,the fault identification matrix is constructed to judge the similarity of zero sequence current waveform between lines,so as to screen out the fault lines.Through theoretical calculation and simulation analysis,it is shown that this method is accurate and reliable,has strong anti-interference ability,needn't to be set,is not affected by the factors such as fault initial phase angle,ground resistance,etc.,and has good reliability and adaptability.To solve the difficult problems of the insulation monitoring of high-voltage power supply network in coal mine,an analysis method of signal noise reduction is proposed based on VMD(Variational Mode Decomposition)and information entropy.The partial discharge model of high-voltage cable of coal mine is established based on the systematic study of the principle of partial discharge and the transmission characteristics of partial discharge signal generated of the cable.The insulation signal can be accurately extracted by using nondestructive testing and the insulation signal can be effectively decomposed by using VMD.After calculating the information entropy of each modal component,the signal can be reconstructed by applying the characteristic component which is decided by the value of information entropy.This method can effectively reduce the noise disturbance and improve the accuracy of the online insulation monitoring on the high-voltage power supply grid in coal mine.The result of the simulation analysis and experimental verification shows that the method can improve the accuracy of the monitoring system and effectively monitor the insulation state of the power supply grid.