基于负荷监测仪的10kV架空线单相断线不接地故障区域判定

Detection method based on load monitoring for 10 kV overhead line single-phase ungrounded open fault area

10kV架空线暴露在外部环境,极易发生单相断线故障,若断线后并未接地,则难以进行检测与定位。针对10kV架空线辐射状的拓扑特点,采用故障分量法分析了单相断线故障的负序电压分布,提出了基于负序电压幅值的单相断线判据。以上述判据为前提,结合负荷监测点到电源点的最小路径分析,提出了基于负荷监测仪的单相断线故障区域判定方法,该方法通过划定发生单相断线故障的可能区域和不可能区域,并将这两个区域作差集运算,得出最小断线故障区域。本方法算法简单,基于实际已有设备,无需额外的设备,且受运行方式影响小,具有较好的实际意义。PSCAD仿真试验及现场试验数据都验证了上述方法的正确性。

Single-phase open fault often occurs in 10 kV overhead lines when exposed to external environment. It will be difficult to detect and localize if the break line is not grounded. According to overhead lines radial topological characteristic, the single-phase open fault criterion based on negative sequence voltage amplitude is proposed by analyzing the negative voltage distribution when single-phase open fault occurs. Combined with the minimum path analysis from load monitoring point to power source point, the detection method based on load monitoring for single-phase open fault area is proposed. The detection method establishes fault possible area and fault impossible area and calculates the minimum area by the subtraction of the possible area and impossible area. This method is simple, based on the existing equipments, little influenced by operation mode and significant in practice. PSCAD simulation test and field test results verify the effectiveness of the proposed method.