小电流接地系统单相接地故障定位方法的研究

Single Phase-to-Ground Fault Location Method for Small Current Grounding System

针对现有方法受对地电容影响大,检测信号不易提取,定位成本高等问题,提出了一种新的针对小电流接地系统单相接地故障的故障定位方法 -特定频率注入法。在满足系统脱谐度和中性点对地电压标准的前提下,在消弧线圈两侧并联高频电源,向系统内注入高频信号,在高频电源支路、线路、接地点、大地之间形成故障电流回路,通过回路电流、电压与回路阻抗的关系,结合均匀线路的性质,确定故障距离测量点的位置。最后使用电力系统仿真软件PSCAD对系统进行了仿真和验证,仿真结果证明,该系统对小电流接地系统进行定位误差小,灵敏度高,适合小电流接地系统的故障定位。

In view of large capacitance to ground,the detection signal is not easy to extract and the high position cost the paper proposes a new fault location for the small current grounding system of single-phase ground fault-special frequency injection method. Under the premise of meet the requirement of off tuning degree and the neutral voltage to ground,a high-frequency power is paralleled with the arc suppression coil. Infuse high frequency signal to the system,and the high frequency power supply branch,lines,ground and the earth formed fault current circuit,through the relationship of the loop current,voltage and impedance,and the properties of uniform line to locate the fault distance measurement point. Finally,the method is simulated and verified with power system simulation software PSCAD. Simulation results show that the method is with small error high sensitivity and suit for fault location.