一种基于特征根的配电网单端故障测距的新方法

A New Method of Single Terminal Fault Location for Distribution Network Based on Eigenvalue

在零序电压、电流中,暂态分量的衰减时间常数及频率与故障距离相关,其值可由象函数特征方程的根表示。分析了该函数与故障距离的关系,提出了一种基于特征根的单端测距方法。该方法结合拉氏变换与双曲函数线路模型,由零序电压、电流象函数的特征方程,得到了象函数测距方程,同时,利用特征频段(SFB)的性质,提出了该测距方程在SFB内的等效形式,通过Prony算法,从采样信息中提取SFB内的特征根,采用搜索法求解超越方程,实现了故障测距。该单端测距方法可准确得到故障距离的解析表达式,且克服了传统双曲函数模型不能用于暂态计算的问题。大量的EMTP仿真实验结果验证了该方法的正确性,不受过渡电阻、故障初始角、中性点运行方式的影响,能够满足实际工程需求。

In the zero-sequence voltage and current, the decay time constant and the frequency of the transient component associated with the fault distance and its value as a image function of the characteristic equation can be expressed in the root. It is analyzed the relationship between the function and the fault distance, and presented a single terminal location method based on characteristic roots. The method combines the Laplace transform with hyperbolic function line model, and obtain image function location equation. Meanwhile, using the nature of the special frequency band（SFB）, it is presented the equivalent form of this equation in the SFB. By Prony algorithms to extract the eigenvalue in the SFB and use the search method of solving equations, to achieve the fault location. The single-Terminal fault location method can be obtained the analytical expressions accurately, and overcome hyperbolic functions of the traditional model which can not be used to calculate the transient problem. EMTP digital simulation results verify the correctness of the algorithm without the impact of transition resistance, fault inception angle, the neutral point operation mode, which can meet the needs of practical engineering.