电缆单端故障测距的阻抗-行波组合法

Impedance-traveling wave assembled method of cable single-terminal fault location

单端故障行波测距的关键在于准确识别故障反射波头与对端母线反射波头。为更准确识别行波波头,提出一种新型阻抗-行波组合法。先由阻抗法粗略计算故障位置,并考虑实际误差,为行波法寻找波头缩小范围,得到多个测距结果。再根据故障反射波头与对端母线反射波头之间相互制约的关系对结果进行筛选,选择最符合条件的一组,同时确认两个波头的到达时间,根据时间点计算故障距离。此法利用两波头间的特定关系,同时找到两个波头,比只查找单个波头更准确,更不易出错。经Matlab和ATP-EMTP仿真验证,方案可行。

The key of single terminal fault location is to identify the fault point reflected wave and the opposite bus reflected wave. In order to identify the wave accurately, a new method combined with impedance measurement and wave, is presented. The impedance measurement method can calculate the location roughly. According to the actual error, the range for wave tip can be narrowed. Then the relationship between fault reflected wave and opposite bus reflected wave can be used to find the time of wave tip. The fault distance can be calculated by the time and the wave velocity. This method finds two wave tips at the same time and the tip time restrict each other, which is more accurate than finding one wave tip only. Matlab and ATP-EMTP simulation results show the method is reliable.