基于多元暂态特征故障度的配电网单相接地选线方法

A single-phase grounding line selection method for a distribution network based onmultivariate transient characteristic fault degree

针对配电网发生单相接地故障时电流较弱、故障条件复杂、现有的故障检测技术性能不可靠的问题,提出一种利用基频移频的多元暂态特征故障度配电网单相接地选线方法。为了保留暂态特征的全景性,去除暂态零序电流中的基频分量,采用希尔伯特变换对暂态零序电流解析信号进行计算。之后,引入位移因子去除基频,保留所有的瞬态特征,并计算了3种典型瞬态特征指标。最后,采用Copula计算瞬态特征随机变量的联合分布密度函数并计算各线路的故障度,选择故障程度最大的馈线作为故障馈线。建立不同故障条件下的径向配电网样本模型、电弧故障模型以及风机和光伏模型的IEEE 34节点测试系统,验证了所提方法的有效性。

When a single-phase ground fault occurs in a distribution network,the current is weak,the fault conditions are complex,and the performance of the existing fault detection techniques is unreliable.Thus this paper proposes a multivariate transient characteristic fault degree distribution network single-phase ground routing method using fundamental frequency shift.To retain the panoramic nature of transient features,the fundamental frequency component in the transient zero-sequence current is removed,and the Hilbert transform is used to calculate the transient zero-sequence current resolved signals.Then,a displacement factor is introduced to remove the fundamental frequency to retain all the transient features.Next,three typical transient feature metrics are calculated.Finally,a Copula is used to compute the joint distribution density function of the transient feature random variables and to calculate the fault degree of lines,and select the feeder with the largest fault degree as the faulty feeder.The effectiveness of the proposed methodology is verified by setting up a radial distribution network sample model,the arc fault model,and the IEEE 34-bus test system for the wind turbine and photovoltaic models in different fault conditions.