Leakage Protection Of Coal Mine Distribution Network Based On Model Parameter Identification

The environment of coal mine is risk and poor, it is easy to accumulate the coal dustand gas. In the coal mine, once the leakage occurs, it may cause personal electric shock,fires and the explosion by coal dust and gas. The process of leakage has complexmechanism, the leakage signal is weak, and prone to be interference, existing leakageprotection methods have some deficiencies, so the leakage fault identification has not beensolved well in coal mine.First, when single phase leakage occur, the mathematical expression of leakagecharacteristic can be obtained by the circuit model of coal mine distribution network andits equivalent model, By the various mathematical expression of leakage characteristic, itcan be found that the main factors which can affect the leakage process are voltage level,insulation resistance r which against the ground, capacitance C which against the ground,leakage resistanceRg, initial phase and the leakage point, and so on.The mathematical model of parameter identification based on least squares algorithmis established by the circuit model of coal mine distribution network. The leakage modelwhich is close to the actual is established in use of MATLAB. Though the simulation ofdifferent leakage, and the data acquisition of zero-sequence voltage and zero-sequencecurrent, then take it into the formula of the insulation parameter identificationmathematical model which based on least squares algorithm, calculate the insulationresistance and capacitance sequence in every line. The leakage line and non-leakage linecan be judged by the average of the insulation resistance and capacitance sequence.Though the MATLAB simulation to the leakage process which is affected by differentfactors, it is verified that this leakage protection can select the leakage quickly andcorrectly In the laboratory build a leakage test system to the coal mine distribution network,for different leakage test. In use of HTLab take the recorded data of zero-sequence voltageand zero-sequence current into the least squares parameter identification algorithmprogram, and calculate the insulation parameters of each line. Though the leakage test, theeffectiveness of the least squares parameter identification leakage protection method isfurther verified.In the paper the leakage Protection scheme of Coal Mine Low Voltage DistributionNetwork Based on Parameter Identification is been designed, mainly composed byTMS320F2812micro-controller, the keyboard circuit, the signal conditioning circuit, theserial port communication circuit, liquid crystal display circuit and so on. And thehardware circuit of each part and software flow chart is been designed.