Research On The Electromagnetic Interference Of Coal Mine Power System To Security Monitoring System

Combining the cooperation project of "The research of the electromagnetic interference on the security monitoring system by the power supply system under coal mine", the thesis focuses on the electromagnetic interference on the parallel security monitoring system signal lines by large electric device’s power line under coal mine. The project undertook by China Coal Research Institute and Beijing Jiao Tong University, is applying "National natural Science Foundation of China" and "15Special Technology Fund of Beijing Jiao Tong University". The main research content is showed as follows:(1) The thesis has described related theory of multiconductor transmission lines, established the model of multiconductor transmission lines, showed several species common solutions such as the finite-difference time-domain method, deducted the voltage and current iteration formulas on all temporal and spatial discrete points of multiconductor transmission lines, and validated the correctness and effectiveness of the algorithm by the cases.(2) By the measurement on the scene, we have got the interference datas on the power line of the large electric devices working normally, extracted the interference source, established the model of multiconductor transmission lines, undertaken interference’s numerical prediction on the safety control signal circuit for different physical and geometry parameters, and analyzed and compared the interference datas we have got.(3) For the switching momentary situation in large electrical equipments, we have selected the representative and typical surge voltage to simulate transient interference on the power line, established the model of multiconductor transmission lines, transformed related parameters, undertaken the transient interference’s numerical prediction on the safety control signal circuit, and held a comparative analysis of the predicted results.(4) We have undertaken the transient electromagnetic interference’s simulation experiment on safety supervision system in the equipment switching moment at China Coal Research Institute. Having undertaken the theoretical prediction before the experiment, we analyzed and compared the experimental results and theoretical results, which verified the correctness and validity of theoretical prediction. (5) For the interference minimization on the safety supervision signal circuit, we have designed and undertaken orthogonal experiment based on the orthogonal optimization method, studied the effects of various parameters on the interference and the best parameter matching which minimize the interference, provided some important theoretical reference and technical support for engineering practice.The results of this research in the thesis can be used to guide the engineering practice, and provide important reference basis for the anti-jamming design and electromagnetic compatibility evaluation of coal mine safety supervision system. In this way, we can realize the effective and real time monitoring for the safety production in coal mines.