Research On The Mechanism And Prevention Measures Of Stray Current In Coal Mine

This subject is an important part of "The Study On Stray Current Distribution and Prevention Technologies of Sihe Coal Mine Power System". This subject is raised for the common accidents contributed by stray current in mine and lack of theoretical research, backward detector.In recent years, with the rising of China’s coal production and the rapid development of the fully mechanized technology, higher requirements have been put forward for hidden dangers monitoring and prevention in each production segment of mine. Fire and explosion accidents caused by stray current in the coal mine security accident is frequent, the study on stray current in coal mines is lagging behind and there is no sufficient theoretical analysis. In addition, due to the special underground working conditions, relevant detection equipment have poor security and low detection accuracy. As a result, it is really essential to analyze the generation mechanism of stray current, to establish a more practical, more accurate model of stray current to predict its distribution, and to develop a stray current detector for underground, which is of great significance to ensure the safe production in coal mine.In this paper, the types of stray current in mine are determined, the formation mechanism of stray current is analyzed and the stray current model is established. Through calculation and simulation, the stray current distribution has been analyzed, the design scheme of detection device has been made, and the hardware circuit design has been completed. Thus, the specific measures to eliminate the harm of underground stray current has been put forward. The main content of this paper is as follows.Through a large number of literature data and practical investigation and study, the type and sources of stray current was summarized, the causes of the stray current was analyzes, the damage caused by stray current was summarized, the mechanism of damage of stray current is analyzed.According to the mechanism of underground DC and AC stray current, model of DC stray current was established based on micro element, the influence to the DC stray current of change of parameters was analyzed with MATLAB. The model of the AC stray current was established based on the lumped parameter and distribution parameter, simulation module was build in the MATLAB, the change of the AC stray current under different cables and three phase earth impedance was compared, the distribution of stray current in underground was summarized.Design scheme of the stray current instrumentation hardware was formulated. The schematic diagram include peripheral circuit of the magnetic resistance sensor, MCU peripheral circuit, level conversion circuit were mapped. Test platform for the hardware circuit include magnetic resistance sensor output verification experiment, magnetic resistance sensor ses/reset performance was set up.Through comparison of the simulation experiment, the main parameters affecting the stray current is analyzed, the existing methods of protection of stray current was compared, the concrete measures to eliminate the underground stray current was put forward on the basis. Finally the purpose of elimination of underground stray current hazards was achieved.