煤矿电网电压互感器故障的PSCAD仿真研究

在煤矿电网中,由于单相接地故障而引起的母线电压互感器(PT)烧毁的现象时有发生。文章依据电网单相接地故障时的等效模型仿真了PT一次侧电流的暂态特性,认为引发PT故障的主要原因为煤矿电网单相接地时电容电流值较大。利用电力系统仿真软件PSCAD/EMTDC对一组6 kV PT进行仿真,并比较了PT一次侧经非线性电阻(消谐器)接地、PT开口三角处并电阻和系统中性点经消弧线圈接地的3种解决措施。文章最后指出中性点经消弧线圈接地是解决煤矿电网中单相接地故障的最合适方法。

PSCAD Simulation Research of Fault of Voltage Transformer of Coal Mine Power Network

The burning out of voltage transformer happens occasionally in coal mine power network(because) of single-phase grounded fault.According to equivalent model of single-phase grounded fault of power network,simulation analysis was presented on the transient characteristics of the primary side(current of PT) in the paper. It was considered that the causation of fault of PT is large single phase-toground capacitive current in coal mine power network.And a group of voltage transformer in 6 kV(distribution) system was simulated based on PSCAD/EMTDC.Three kinds of eliminating resonance method in(different) condition were compared including connecting a nonlinear resistance to neutral point of high(voltage) side of three-phase PT,connecting a damping resistance to the secondary assistant windings of three-phase PT,grouding neutral point through arc suppression coil.At last the paper indicated that(neutral) grounded by arc extinction coil is the best solution of single-phase grounding fault in coal mine(power network).