基于广义S变换的有源配电网故障定位方法

Fault location method for active distribution network based on generalized S transform

有源配电网中,DG中性点接地方式的不同选择将对原有故障电气量造成不同影响。从小电流接地系统与DG中性点接地方式安全配合的角度分析可知,DG采用中性点不接地方式最佳,并由此得出了其暂态零序电流不受DG接入影响的结论。在此基础上,针对故障信息利用不充分且单一判据存在定位盲区的问题,提出一种基于广义S变换多维判据的故障定位方法,对暂态零序电流信号进行广义S变换处理,不仅利用其幅值矩阵故障信息提取了主谐振频率和暂态能量特征量,还提出利用常被忽略的相角矩阵构造了统计极性特征量,构建了完备的多维故障区段判据。通过依次比较两检测点任一故障特征量,差异较大则判定为故障区段。理论分析与仿真验证表明该方法能够有效、准确地定位故障区段,且具有较强的适用性。

In the active distribution network,different choices of the DG neutral point grounding method will have different effects on the original fault electrical quantity.From the perspective analysis of the small current grounding system and the DG neutral point grounding method,it can be seen that the DG adopts the neutral point un-grounding method,and the conclusion that the transient zero-sequence current is not affected by the DG access is obtained.On the basis of this,in order to solve the problem that the fault information is not fully utilized and the single criterion has the location blind zone,a fault location method based on the generalized S transform multi-dimensional criterion is proposed to perform the generalized S transform on the transient zero-sequence current signal.The main resonance frequency and the transient energy feature quantity are extracted by using the amplitude matrix fault information.It is also proposed to construct the statistical polarity feature quantity by using the often neglected phase angle matrix,and a complete multi-dimensional fault section criterion is constructed.By comparing the fault feature quantities of the two detection points in turn,it is determined as the fault section if the difference is large.Theoretical analysis and simulation results show that the proposed method can locate fault sections effectively and accurately,and has strong applicability.