小电流接地故障发生后,为使有源消弧法在配电网线路可能发生切换的情况下仍具有良好的消弧性能,提出了能适应线路结构动态变化的有源消弧算法。故障发生后,注入电流并测量母线零序电压,计算接地电阻。在接地电阻较大时,忽略线路压降,控制故障相电压为0,即采用电压消弧法;在接地电阻较小时,利用配电网自动化装置计算故障后配电网零序导纳,控制故障点电流为0,即采用电流消弧法。仿真结果验证了所提算法的有效性。
To make active arc-suppression method still remaining satisfied arc-suppression performance under possible switching over of distribution line after the occurrence of small current earth fault, an active arc-suppression algorithm adaptable to the dynamic structure variation of transmission line is proposed. After the occurrence of small current earth fault, injecting current, through injecting current and measuring zero-sequence voltage of the bus the grounding resistance can be calculated. For higher grounding resistance, neglecting voltage drop on transmission line the current in the fault phase is controlled to be zero, it means to adopt the voltage-based arc-suppression method; for lower grounding resistance, the distribution automation device is utilized to calculate the post-fault zero-sequence admittance of distribution network and the current at the fault position is controlled to be zero, namely the current-based arc-suppression method is adopted. The correctness of the proposed method is validated by simulation results.