一种雷电波侵入变电站的扰动识别方法

雷击输电线路既可能导致保护误动作,又可能侵入变电站,引起系统过电压,为此提出了一种基于信号S变换的雷电侵入波对电网的扰动监测及其识别方法。基于变电站母线电压实时监测信号,利用S变换技术提取电压暂态信号在时域和频域内的波形特征,根据信号的主要谐波次数及其幅值大小和基波电压跌落差异,构建了普通短路故障、故障性雷击与非故障性雷击和其他扰动信号的识别判据。PSCAD仿真结果表明,该方法不受故障类型、故障接地电阻、故障初始时刻、雷击相别及雷电流大小的影响,识别灵敏度较高。

A Method to Identify Disturbances Caused by Lightning Wave Invading Into Substation

Lightning stroke on transmission line not only may lead to maloperation of protective relaying,but also the lightning wave invading into substation may cause overvoltage.For this reason,a method,which is based on the S transform of signal,to monitor and identify the disturbances caused by lightning wave invading into substation is proposed.Based on real-time monitoring signals of substation busbar voltage,the waveform characteristics of transient voltage signal in both time-and frequency-domain are extracted by S transform,and according to the orders of main harmonics of the signal and their amplitudes as well as the differences among voltage sags of fundamental voltage,the criteria to identify generic short-circuit fault,lightning stroke causing equipment failures,lightning stroke not causing equipment failures and other disturbance signals are proposed.Simulation results by PSCAD show that the proposed method is not affected by fault type,grounding resistance,initial time when fault occurs,the phase on which the lightning strikes and the value of lightning current,and the proposed method can provide a higher identifying sensitivity.