基于线路参数修正的同杆双回线故障定位方法

当电力系统在功率低频振荡等动态情况下发生故障时,电力信号的幅值和频率往往表现出一定的动态特性,然而目前大部分同杆双回线故障定位方法并未考虑这一因素.为此提出了动态条件下基于线路参数修正的同杆双回线故障定位方法,新方法拓展了传统的静态信号模型,建立时变的信号模型使其能正确表示信号的动态特性,并加入基于同步相量测量单元(phasor measurement units,PMUs)的动态同步相量测量算法估计的信号相量值,从而可以在动态条件下精确修正线路参数,最后通过牛顿迭代算法得到准确的故障距离.应用PSCAD/EMTDC软件模拟各种工况对算法进行验证,仿真结果表明:与传统的算法相比,经过线路参数修正的方法在动态条件下具有较高的故障定位精度,并且不受故障位置、过渡电阻、故障类型和故障初始角的影响.

Fault Location for Double-Circuit Transmission Lines on Same Tower Based on Modification of Transmission Line Parameters

Most existing fault location methods for double-circuit transmission line on the same tower did not consider the factor that power signal’s amplitude and frequency were often indicative of certain dynamic characteristics while power system fault occurred during dynamic conditions such as lower frequency power oscillation.Based on the modification of transmission line parameters,a fault location method for double-circuit transmission line on the same tower was proposed.In the proposed method,traditional static state signal model was expanded and a time-varying signal model was built to correctly express dynamic characteristics of signals,and the values of signal phasors estimated by dynamic synchronous phasor measurement algorithm based on phasor measurement units(PMUs) were added,thus the parameters of transmission line could be accurately modified under dynamic condition,finally accurate fault distance could be obtained by Newton iteration algorithm.The proposed method was verified by PSCAD/EMTDC-based simulation under various operating conditions,and simulation results showed that comparing with traditional fault location methods the fault location results of double-circuit transmission line on the same tower by the proposed method,in which the transmission line parameters were modified,were more precise and not independent of fault position,transition resistance,fault types and initial phase angle at which the fault occurred.