一种基于频率选择的输电线路故障行波测距方法OA

In order to solve the problem that the high frequency of traveling wave makes the wave head amplitude lower,which leads to the failure of fault location,this paper proposes a frequency selection based traveling wave fault location method by analyzing the effect of frequency on the traveling wave head amplitude.Firstly,the empirical mode decomposition(EMD)of the fault traveling wave signal is done to obtain the intrinsic mode function(IMF)components of different frequency bands.The Hilbert transform and first-order differentiation are done on the IMF components,and the amplitude-time curves corresponding to the different high-frequency IMF components are extracted and plotted,so that the traveling wave head can be detected by selecting the high-frequency IMF components with larger amplitude of the wave head and lower frequency.Thus it reduces the impact of signal attenuation caused by excessive travelling wave frequency,and ensures the accuracy of the wave head detection.Finally,the fault location is completed the three-terminal traveling wave location algorithm.Simulation results show that the relative error of the method proposed in this paper is basically within 0.3%,and the absolute error is within 0.9km,which has higher location accuracy compared with the traditional instantaneous frequency location method.