煤矿6kV动力电缆绝缘在线监测系统研究

Research on online monitoring system of coal mine 6 kV power cable insulation

针对煤矿井下6 k V供电系统电缆离线检测的不足,设计了一种电力电缆在线监测系统,并进行了实验验证。在供电系统中注入低频电压作为系统的激励信号,运用设计的监测单元对分支电缆的低频电压和低频电流信号进行调理和精确测量,采用高性能信号处理器结合矢量方程和全波傅里叶算法,计算出所有电缆分支的对地绝缘电阻值。同时运用CAN总线建立监控系统实现了电缆线路的故障选线。实验结果表明,监测系统有效的解决了线路电抗和互感器电抗参数以及不平衡电流对测量精度的影响,可以实时监测所有电缆分支的对地绝缘电阻值,测量误差在3%以内。

Aiming at the disadvantages of offline detection of mine 6 kV power cable supply system, an online mo- nitoring system of power cable is designed and tested. A low voltage frequency signal is injected as excitation signal into power supply system, the designed monitoring unit is used to regulate and measure the low frequency voltage and current signals of each branch cable. Using high performance signal processor based on vector equation and full-wave Fourier algorithm, all the branch cable insulation resistance value is computed. The CAN bus monitoring system realizes the selection of fault line. The experimental results show that the monitoring system effectively solves the influences of the line reactance and transformer reactance parameters and the unbalance current on measuring precision, the system can real-time monitor the insulation of the branch cable resistance, the measurement error is within 3%.