基于R-L模型参数辨识的输电线路准确故障测距算法

输电线路的准确故障测距对于保障电力系统安全稳定运行具有重要的意义。该文充分利用了故障分量提供的故障信息，以模量分析与输电线路R-L模型为基础，提出了一种将故障状态网络的微分方程与故障分量网络的微分方程联立求解的单端量时域准确故障测距算法。该算法将故障距离、过渡电阻以及对侧系统的运行参数作为模型的未知参数进行求解辨识，利用数值微分代替测距方程中的一阶与二阶微分，消除了传统单端量故障测距算法中主要由于对侧系统实时运行参数未知而引起的原理性误差。该算法不受故障时系统的运行方式、网络结构以及电网频率波动影响。大量EMTP仿真表明，算法原理正确且具有较高的测距精度，在故障距离20—280km范围内测距的平均误差为0．0796％，最大测距误差小于0．173％，该误差主要来自截断误差，即用差分法计算时域连续信号的微分时所产生的误差。

AN ACCURATE FAULT LOCATION ALGORITHM FOR TRANSMISSION LINES BASED ON R-L MODEL PARAMETER IDENTIFICATION

Accurate transmission lines fault location is important for power industry. In this paper, an accurate time domain algorithm for fault location using one-terminal data is presented. The algorithm is based on the modal analysis and the R-L model of transmission lines, and fully utilizes the effective information provided by fault-superimposed components. The differential equations of fault network and pure-fault network are employed to determine the fault distance. The fault distance, fault resistance and source parameters at the remote end are solved as the unknown variables of system model, so the theoretical error of conventional one-terminal approaches is eliminated completely. Fault resistance, system operation mode and network configuration do not affect fault location accuracy of the proposed method. The simulation results demonstrate the validity and high accuracy of new algorithm. In the average location error is 0.0796% from 20 to 280 kilometers, and the maximum error is not more than 0.173%. The truncation error is the primary error source of this algorithm, and it results mainly from using the difference calculation as a substitute for the differential calculation.