配电混合线路双端行波故障测距技术

该文提出利用线路故障产生的暂态行波实现配电架空线、电缆混合线路单相接地及相间短路故障测距,分析了故障初始行波模分量的暂态特征。研究发现,尽管中性点非有效接地系统单相接地故障后线路稳态线电压保持不变,但其故障暂态过程仍产生行波线模分量,这样单相接地及相间短路故障均可利用参数比较稳定的行波线模分量作为测量信号。分析表明行波在配电混合线路传播过程中发生复杂的折、反射,应该利用双端行波测距法测量故障距离。针对架空线和电缆波速度不一致的问题,给出了基于时间中点的故障点搜索算法。分析了电压、电流行波在线路末端的反射规律,为选择合适的行波测量信号提供了理论基础。现场试验表明文中所述方法可行有效。

Study on Fault Location of Distribution Mixed Feeders Based on Double Terminal Method of Traveling Waves

Using transient traveling waves generated by fault to locate single-phase earth fault or short circuit fault in distribution feeders mixed with overhead lines and cables is proposed.Transient characteristics of mode component of original traveling waves generated by fault are analyzed,the results show that transient process of single-phase earth fault in neutral non-effective grounding systems produce aerial mode component of traveling waves,though stable state of line-to-line voltage keeps constant after fault is occurred.Therefore,either single-phase earth fault or short circuit fault can use aerial mode component of traveling waves with steady-parameter as measurement signals.Traveling waves will refract and reflect complexly in distribution mixed feeders when it transmits in distribution feeders,so double terminal method of traveling waves is suitable for the fault location.Aiming at the difference of wave rate in overhead lines and cables,fault point seeking algorithm based on time mid-point is proposed.On the basis of analyzing reflection rules of voltage traveling waves and current ones in the end of the feeders,principle of choosing right traveling waves measurement signals is proposed.Experimental test verify the feasibilities and correctness of the proposed method.