基于电流波形曲率的短路故障快速识别方法

A Method to Fast Recognize Short-Circuit Fault Based on Curvature of Line Current Waveform

随着电力系统的迅速发展,短路电流超标已经成为突出问题。故障电流限制器(fault current limiter,FCL)可以在不改变电网潮流分布的情况下限制短路电流,具有良好的应用前景。如何快速准确地识别出短路故障是故障电流限制器使用效果的关键因素之一。针对短路故障发生时线路电流会发生突变这一特性,提出了一种采用线路电流波形曲率对故障电流快速识别的方法。用PSCAD仿真软件建立了华东500 kV电网故障电流限制器等值系统。在该等值系统上对基于线路电流波形曲率的故障信号快速识别方法进行了研究。结果表明该方法对短路电流突变特性有识别能力且对识别速度有提高作用。最后通过伊敏—冯屯可控串补工程现场故障录波数据验证了上述结论。

With rapid development of power grids in China,the fact that short-circuit currents exceed specified limits becomes a troubled problem.Fault current limiter（FCL） can restrict short-circuit current under the prerequisite of not changing power flow distribution in power grid,so it possesses a good application prospect.It is one of key factors influencing the application effect of FCL to recognize short-circuit fault rapidly and accurately.Based on the feature that there is abrupt change of line current during the short-circuit fault,a method to rapidly recognize fault current by use of curvature of line current waveform is proposed.An equivalent system of FCL used in 500kV East China power grid is built by PSCAD software,and the fast fault signal recognition method based on the curvature of line current waveform is simulated by the built system.Simulation results show that the proposed method possesses the ability of recognizing abrupt change of line current and the recognition speed is fast.Finally,simulation results are verified by on-site recorded fault data come from controllable series compensation for a UHVAC transmission system project.