基于μPMU同步量测数据的配电网故障定位方法

通过在辐射型多分支配电网络配置微型同步相量测量单元(μPMU),提出了一种基于μPMU同步量测数据的配电网故障定位方法。该方法首先通过单端μPMU电压、电流同步相量求取初始故障距离。然后,根据双端μPMU电压、电流同步相量排除伪故障点,迭代确定故障在主网络上的具体位置,通过与初始故障距离比较,判断故障发生在主网络还是分支线路上。最后,通过伪故障点的迭代排除,确定分支上故障到主网络的距离。该方法考虑了线路电容对故障定位精度的影响,通过线路对地电容分析,减小了定位误差。仿真结果验证了该方法的有效性。

A fast boundary protection for an AC transmission line connected to an LCC- HVDC inverter station

For AC transmission lines connected to an LCC-HVDC inverter station, commutation failure can lead to the wrong operation of traditional protection. To solve the problem, this paper proposes a fast protection scheme using transient information from one end of the AC line. The boundary frequency characteristics of the AC line connected to LCC-HVDC inverter are analyzed first. This reveals the existence of significant attenuation on both high frequency signals and some specific frequency signals. Based on the boundary characteristics, a novel boundary protection principle utilizing a backward traveling wave is then proposed. A PSCAD/EMTDC simulation model of a±800 kV LCC-HVDC and 500 kV AC transmission system is established, and different fault cases are simulated. The simulation results prove that the novel protection principle is immune to commutation failure, fault resistance and fault type.