电压型配电网接地故障自动隔离方法研究

Research on Automatic Ground Fault Isolation Method for Voltage-Type Distribution Network

当发生接地故障时,必须及时发出跳闸命令、断开路由器,以保证配电网安全运行。提出了一种电压型配电网接地故障自动隔离方法。首先,通过小波分析和公共空间模式算法分解零序电压,提取时-频-空域特征,以更好地刻画故障的本质特征、提高故障自动隔离的准确性。然后,构建电压型配电网接地故障特征向量,采用多域特征和相关向量机(RVM)展开特征选择,确定接地故障发生区段。最后,通过零序电压判断是否启动保护。如需保护,则采用分布式处理方式完成故障自动隔离。试验结果表明,采用该方法得到的故障定位距离和实际故障距离更接近,说明该方法定位误差较小。根据故障定位结果可以准确判别故障区段,实现接地故障自动隔离,并且隔离过程中不需要借助额外设备。该方法的接地故障隔离自动化水平较高,具有实际应用价值。

When a ground fault occurs,a trip command must be issued in time to disconnect the router to ensure the safety of distribution network operation.An automatic ground fault isolation method for voltage-type distribution network is proposed.Firstly,the zero-sequence voltage is decomposed by wavelet analysis and common space pattern algorithm,and the time-frequency-space domain features are extracted to better portray the essential characteristics of the fault and improve the accuracy of automatic fault isolation.Then,the ground fault feature vector of voltage-type distribution network is constructed,and the multi-domain features and relevance vector machine(RVM)are used to expand the feature selection and determine the ground fault occurrence zone.Finally,the zero-sequence voltage is used to determine whether protection is activated or not.If protection is needed,distributed processing is used to complete automatic fault isolation.The test results show that the fault localization distance obtained by this method is closer to the actual fault distance,indicating that the method’s localization error is small.According to the fault location results,it can accurately identify the fault section and realize automatic ground fault isolation,and the isolation process does not need to use additional equipment.This method has a high level of ground fault isolation automation and has practical application value.