基于故障分量原理的配电网高阻接地故障检测方法

配电网中发生高阻接地故障时,短路电流小于传统过流保护的阈值,无法被常规保护装置检测和清除。若不及时消除短路电路,极易演化成严重故障。针对该问题,文中首先分析发生高阻接地故障时配电网的故障分量特征和基于母线处的正序电压故障分量与其相连接的各馈线正序电流故障分量的相位差特征,给出适用于配电网高阻接地故障检测的故障判据。然后,为解决配高阻接地故障检测过程中系统不平衡引起的一系列问题,制定了相应的故障检测启动判据。基于该故障检测判据和启动判据,制定基于故障分量原理的配电网高阻接地故障检测方法。最后,在PSCAD/EMTDC仿真软件中建立含架空线路的中压配电网模型,仿真结果验证了所提高阻接地故障检测方法的正确性。

High impedance grounding fault detection for distribution networks based on fault component principle

The short-circuit current value of distribution network is small when high impedance grounding faults (HIGFs) occur,which cannot be detected tripped by the traditional over-current protection devices. If short-circuit cannot be tripped in time,it will lead to serious results. To solve the above problems,the fault components of microgrid in the operating conditions of HIGFs are analyzed. The phase differences characteristics between positive-sequence fault component of bus voltage and positive-sequence current fault components in the feeders are explained in detail. And based on the phase differences characteristics,the fault criterion for HIGFs in distribution network is proposed. Meanwhile,to overcome those problems caused by the imbalanced distribution network,the starting criterion is proposed. Based on the above fault criterion and the starting criterion,the new fault detection method is proposed. Finally,a medium distribution with the model of overhead lines is established in PSCAD/EMTDC,and simulation results verify the correctness of the fault detection method.