不依赖时间同步的多分支配网故障精确定位方案研究

摘要

为在不借助时间同步的前提下实现多分支配网故障精确定位的目标,提出一种故障定段与行波测距相结合的方法.针对由线路参数频变特性引起的行波色散效应,设计了一种有效的低通滤波器,提取出零模、线模行波中以工频为主的、速度稳定的低频分量,进而实现了基于单端量行波测距的故障精确定位.针对由离散采样机制引起的截断误差问题,提出了一种改进修正算法,在各种系统采样率下均可充分提高故障测距精度.通过 PSCAD/EMTDC 仿真平台,计及线路参数的频变特性,搭建典型 10 kV 多分支配网模型,验证了所提方法的可行性与有效性.%To figure out the fault location precisely independent of time synchronization in the distribution network with multiple branches, a novel method combining fault section locator and traveling-wave based fault locator is presented in this paper. In view of the wave dispersion effect caused by the frequency variation of the line parameters, the low frequency component of ground mode and aerial mode traveling wave is extracted by low-pass filter, then the fault distance is calculated based on the stable velocity difference between the low frequency components. In addition, aiming at eliminating the truncation error caused by the discrete sampling mechanism, through the improved correction algorithm proposed, the fault location accuracy can be improved fully under various system sampling rates. Finally, a typical 10 kV distribution network model is built in the PSCAD/EMTDC simulation platform, verifying the feasibility and effectiveness of the proposed method.