风电场并网输电线路单相接地故障单端测距方法

采用故障后及单相跳闸后2个时间断面的信息构建方程描述输电线路两侧断路器之间的网络拓扑,能够实现输电线路故障单端精确测距。但该方法假设2个时间断面下量测点对端系统阻抗保持不变且故障支路恒定,使得现有立足风电场并网输电线路系统侧开展测距的常规做法失效。针对该问题,提出了立足风电场侧面向于系统侧开展测距研究的思路,克服了量测点对端系统阻抗在2个时间断面下变化的问题;针对测距算法中使用迭代搜索解法带来的风电场侧电流量测值偏小导致的高阻故障测距精度显著下降的问题,提出了不受故障类型影响的直接求解方程测距新算法,能够直接计算得到故障距离和过渡电阻值,不仅实现了精确测距且对于后续的自适应重合闸研究提供了新思路。

Accurate single terminal fault location algorithm for single-line-to-ground fault in transmission lines with wind farm connection

The accurate single terminal fault location can be realized by using data of two time sections to set up equations to describe the constant transmission line topology between two-terminal circuit breakers, the time after fault and that after single-phase circuit breaker tripping. But this method assumes that the impedance of opposite terminal and fault resistance in fault branch are constant between two time sections, which is untenable at the system side in transmission lines with wind farm connection. For this problem, the idea of operating fault location at the wind farm side is proposed to overcome the problem of equivalent system impedance variation between two time-sections. And then a new fault location equations direct calculation algorithm is proposed to resolve the problem of low fault location accuracy in the case of high impedance faults, which is usually produced by the previously adopted iterative searching algorithm. Fault distance and transitional resistance can thus be directly obtained using the new algorithm while subsequent research on adaptive reclosing is provided with a new line of thought. This work is supported by National Natural Science Foundation of China(No. 51477084)and State Key Laboratory of Power System(No. SKLD16Z07).