基于小电流灵活接地的单相接地处理

Single-phase Grounding Fault Treatment Based on Small Current Flexible Grounding

为了更好地利用中性点不接地和经消弧线圈接地的运行优点,更好地应对电力系统发生的单相接地故障,提出一种基于小电流灵活接地方式的单相接地故障处理及控制方法。通过开关控制消弧线圈的投切完成系统中性点不接地方式和经消弧线圈接地方式之间的转换,系统正常运行时消弧线圈为断开状态,若系统发生单相接地故障,迅速采集故障零序信号后,马上投入消弧线圈进行补偿。利用采集获得的故障零序信号,大大提高故障选线的准确性。通过对本控制流程中的故障选线和消弧线圈补偿效果等方面的分析,并用Matlab建立仿真模型进行仿真分析,大量仿真表明该方法的正确性和可行性。

In order to make better use of the operating advantages of neutral point ungrounding and arc suppression coil grounding,and to better deal with single-phase ground fault conditions in power systems,a single-phase ground fault treatment and control method based on small current flexible grounding is proposed.The changeover between the main arc suppression coil grounding and the neutral point ungrounding mode of the system is realized by the switching of the main arc suppression coil.The main arc suppression coil is disconnected during normal system operation,and if the system has a single-phase ground fault,the arc suppression coil is switched on immediately to compensate after quick acquisition of fault zero sequence signal.The fault zerosequence signal obtained through acquisition can greatly improve the accuracy of fault line selection.Through the analyses of the fault line selection and the compensation effect of the arc suppression coil in the control process,and the simulations based on the Matlab model,a great deal of simulations show the correctness and feasibility of the method.