Selective Leakage Protection Research Of Low-Voltage Reactive Power Compensation Device In Underground Mine

After the single-phase earth fault of the reactive power compensation device in underground mine low-voltage power distribution network,the faulty capacitor bank cannot be judged accurately by the protection of traditional low-voltage reactive power compensation device,due to the complex operation mode of the underground power grid,and the reactive power compensation device is cleared by leakage protection device in a short time after the fault,the quick and accurate judgement of the faulty capacitor bank with the fault information is a problem that needs to be solved.In summary,the further research of selective leakage protection of mine low-voltage reactive power compensation device is needed.The traditional small-current grounding line selection method is referred in this paper,group comparison of amplitude and phase method is used for the fault capacitor bank selection in isolated neutral system.The modified zero-sequence current break variable method is used for the fault capacitor bank selection in the neutral point arc-extinguishing coil grounding system.The grid-connected parallel capacitor bank model is established to process the ground fault simulation experiment,the characteristics of single-phase ground fault are verified.Finally,the underground mine low-voltage reactive power compensation device model is established with MATLAB,the protection method is used in the simulation verification,the results show that the proposed selective leakage protection method has high accuracy and strong adaptability.In addition,because the reactive power compensation device is cleared by leakage protection device in a short time after the fault,in order to verify the rapidity of the protection method,the MATLAB simulation model is used in this paper,the rapidity of the protection method is verified with the fault information of two power frequency cycles after the fault.The simulation results show that the fault can be accurately selected by the proposed method in two power frequency cycles,some of the algorithm errors can be eliminated,and the accuracy of the judgment is improved.