针对电压监测器记录下配电变压器低压侧接地故障难以准确定位的问题,本文提出基于负序电压变化的优化电压骤降(Vdip)方法。首先,通过非对称故障定位概率计算方法比较馈电变电站的负序电流和配电变压器低压侧负序电压确定不对称故障定位的概率;然后,基于此概率对接地故障定位进行确认;最后,针对频率偏差和间谐波等问题,提出基于滑动窗平均的间谐波消除方法。通过对谐振接地配电网短接辅助电阻进行仿真试验,并在某地区电网22 kV谐振接地网络中进行验证,其中平均接地故障定位误差为1.06 km。试验结果表明,本文方法可在规避间谐波干扰下,实现高达98.7%的故障定位精确率,且模型各性能指标均优于现有方法。

To address the problem that the voltage monitor has difficulty accurately locating ground faults on the low-voltage side of the distribution transformer, this paper proposed an optimized voltage dip (Vdip) method based on negative sequence voltage changes. First, the asymmetric fault location probability calculation method was used to compare the negative sequence current of the feeder substation and the negative sequence voltage on the low-voltage side of the distribution transformer to determine the probability of asymmetric fault location. Then, based on this probability, the ground fault location was confirmed. Finally, to address issues such as frequency deviation and inter-harmonics, an inter-harmonic elimination method based on sliding window averaging was proposed. Through simulation experiment on the short-circuited auxiliary resistance of the resonant grounding distribution network, and verified in a 22 kV resonant grounding network of a certain regional power grid, the average ground fault location error was 1.06 km. Experimental results showed that the proposed method could achieve a fault location accuracy of up to 98.7% while avoiding inter-harmonic interference, and the model performance metrics were better than existing methods.

海南电网科技项目(070400KK52220001)