基于负序电压幅值差的配电网单相断线接地复合故障区段定位方法OA

To address the challenges of low sensitivity and high misjudgment rates in detecting single-phase open-circuit faults in distribution networks,due to their diverse fault forms and lack of distinct current characteristics,a section location method based on the magnitude difference of negative-sequence voltage is proposed.First,a unified analytical model for various types of single-phase open-circuit faults is established,and the relationships between phase voltages and negative-sequence voltages on the source side and load side at the breakage point are derived.The results show that under various complex fault scenarios,including open-circuit without grounding,single-side grounding,and double-side grounding(Rd＞5 Ω),the negative-sequence voltage on the source side is close to zero,while that on the load side exceeds 0.3 times of the normal voltage.Moreover,a significant difference in negative-sequence voltage magnitude exists only across the faulted section,whereas adjacent non-faulted sections exhibit nearly identical values.Based on this characteristic,the method further utilizes low-voltage side measurements from intelligent terminals of distribution transformers to estimate the medium-voltage line negative-sequence voltage.A fault section location scheme is then constructed using the magnitude differences of negative-sequence voltages between adjacent sections.Simulation results verify that the proposed method achieves reliable fault section localization under various compound single-phase open-circuit grounding fault conditions.