适应线路参数及负载变化的配电网柔性优化消弧方法

中性点非有效接地配电网长期存在单相接地故障消弧难题,在分析线路参数及负载对已有消弧方法的影响以及已有消弧方法优缺点的基础上,提出一种配电网单相接地故障柔性优化消弧方法。故障发生后,通过级联H桥变流器向配电网注入接地故障补偿电流,并根据母线处零序电压确定接地过渡电阻大小。接地电阻较大时,判断注入补偿电流后母线处三相电压变化趋势,选出故障相,根据故障选相结果调整变流器注入电流,控制母线处故障相电压为零,即采用电压消弧方法,否则继续注入接地故障补偿电流,即采用电流消弧方法。仿真结果表明所提方法能够有效抑制接地电弧重燃,解决了单一电流消弧方法和电压消弧方法因线路参数和负载影响而存在的不足。

Flexible Arc-suppression Optimization Method for Distribution Network Adaptable to Variation of Line Parameters and Load

Arc extinguishing of grounding faults is a problem for neutral non-effective grounding distribution networks. In consideration of line parameters and load, a flexible arc-suppression optimization method under the single-phase-to-ground fault in the distribution network is proposed. When a single-phase-to-ground fault occurs, the compensation current is injected by a cascaded H-bridge converter. By measuring the zero sequence voltage of the bus, the grounding resistance can be calculated. For the higher grounding resistance, the fault phase is selected according to the variation trend determined of the three-phase voltage on the bus after compensation current injection. Then the voltage in the fault phase is controlled to be zero by adjusting the injection current according to the result of fault phase selection, which means to adopt the voltage-based arc-suppression method. Otherwise, the compensation current will be injected continuously, which means to adopt the current-based arc-suppression method. The simulation result has proved that the proposed method is able to suppress the arc flexibly and effectively and overcome the shortages of current-based and voltage-based arc-suppression methods due to line parameters and load. This work is supported by National Natural Science Foundation of China(No. 51677030)and Fujian Provincial Natural Science Foundation of China(No. 2016J01218).