The Study On Improving Technology Of Power Supply System Safety And Reliability In Coal Mine

Coal is one of the main energy sources in China.The safe and reliable operation of coal mine power supply system is directly related to the safe production of coal mine.With the application of new mining technology,automatic control technology and high-power equipment,coal mine power supply system has become more complicated.In addition,the improper coordination of relay protection and adjustment results in overstepping,the long power supply radius in the mining area leads to too low terminal voltage,the start of high-power equipment has an impact on the coal mine power system,and insufficient over-voltage protection measures have led to equipment damage.Therefore,in order to ensure the safe production of coal mines,it is very important to improve the reliability of coal mine power supply system.On the basis of theoretical analysis of the problems existing in the power supply system of the coal mine,the paper mainly focuses on the calculation of relay protection of the mine power supply system,the lightning protection improve of the 10kV overhead line,and Inrush exciting current of the no-load Transformer.The problems are analyzed and solved to improve the reliability of the power supply system in the coal mine.First of all,the problem of overstepping is caused by the improper coordination of relay protection values of the power supply system in the coal mine.Considering the rated parameters and operating parameters of the system,the combination of forward calculate and reverse calculate methods has been used to re-adjust the value of the power supply system in the coal mine.The calculation has ensured the speed and reliability of relay protection,taking into account selectivity and sensitivity,and reducing the scope of power outages.Second,for two major accidents in which the main Transformer was damaged by protection angle of the lightning line,the lightning rod tower was used to set up the lightning rod line,and some of the pole towers were equipped with line arresters,and three-dimensional grounding devices were used to make lightning protection grounding.The lightning trip rate was reduced to less than 1%,which ensured the safety of electrical equipment and the reliability of power supply in the coal mine.Thirdly,the damage accident of rectifier Transformer in the main inclined shaft driver room in the coal mine is studied by simulation and field test.By comparing the simulation results with the test results,it is found that the main reason for the damage of rectifier Transformer is the excitation inrush current generated during the no-load closing.The excitation inrush current Suppressor is used to solve the practical problems in the field.Finally,statistical analysis of the operation of the power supply system in the coal mine is carried out.The results show that the problems existing in the power supply system have been completely solved through above three mothods.The failure rate of the power supply system has been greatly reduced,and the operation reliability of the power supply system has been improved significantly,ensuring the safe production in the coal mine.