基于衰减指数的主动配电网纵联保护新方法研究

Research on a New Method of Longitudinal Protectionof Active Distribution Network Based on Attenuation Index

根据光伏并网系统中光伏与大系统电源故障输出特性的差异,提出一种基于电流衰减指数的主动配电网保护新原理.首先对采集的保护线路首、末端电流进行滤波、去噪,以避免噪声造成Prony计算不精确的问题;再将线路首、末端电流衰减指数作差与给定门槛值比较,以便判断故障区域;最后通过改变故障位置、故障距离以及光伏渗透率,验证该方法在不同情况下的适用性.通过Matlab仿真实验表明本文提出的方法能够准确判断线内、线外故障,并且其对判断故障相有一定效果.

According to the difference between the power fault output characteristics of photovoltaic and large systems in photovoltaic grid-connected systems,this paper proposes a new principle of active distribution network protection based on current attenuation index.Firstly,the first and end currents of the collected protection lines are filtered and denoised to avoid the problem of inaccurate Prony calculations caused by noise.Thens compareit the current attenuation index at the end of the line with the given threshold value to determine the fault area.Finally,by changing the fault location,fault distance and photovoltaic permeability,the applicability of the method in different situations is verified.MATLAB simulation experiments show that the method proposed in this paper can accurately determine the faults inside and outside the line,and it has a certain effect on determining the fault phase.