Research On Mine Leakage Protection Based On Insulation Parameter Identification

Leakage faults,as one of the vital faults of the mine low-voltage power system,seriously threaten the safety of mine operators and the safe power supply of mines.The development of a safe,reliable and fast low-voltage mine leakage protection can provide guarantee for the safety of mine operators and the safe power supply of mines.This article introduces several traditional leakage protection principles in detail,and proposes a leakage protection method based on variable forgetting factor least squares insulation parameter identification.This method is based on the variable forgetting factor least squares algorithm,and uses the zero sequence current and zero sequence voltage signals of each branch to identify the insulation parameters.The insulation parameter identification results of the leakage fault branch and the non-fault branch are significantly different,so as to realize reliable and fast adaptive leakage protection.This paper uses PSCAD software to build a low-voltage 1140 V coal mine underground power supply system,and compiles the variable forgetting factor least squares insulation parameter identification algorithm in the M file of the MATLAB software to identify the insulation parameters of the low-voltage mine power supply line.The simulations were achieved under three representative working conditions of different leakage resistance,different initial phase angle of power supply voltage and different leakage point positions.The simulation results show that under different working conditions,there are significant differences in the polarity of the faulty branch and the non-faulty branch in the insulation resistance to ground and the insulation capacitance to ground.The leakage protection device designed by using this difference is more accurate and faster.And the advantages of strong anti-interference.Finally,a low-voltage mine leakage protection device is designed based on the principle of variable forgetting factor least squares insulation parameter identification.Altium Designer software is used to develop and devise the hardware circuit of the leakage protection device,including: microprocessor,reset circuit,crystal oscillator circuit,zero sequence voltage signal conditioning circuit,zero-sequence current signal conditioning circuit and serial communication circuit.The software of the leakage protection device including main program,initialization program and interrupt program is designed,and several software and hardware anti-interference measures are also given.