Research On Fault Traveling Wave Signal Analysis Method Based On Wigner Ville Distribution

When the power line fails,the generated traveling wave signal is a multi-component,non-linear,wide-band non-stationary transient signal.There is a large number of waveform characteristic information reflecting the position of the fault point,the type of fault,the degree of fault,and the duration of the fault in a certain time and frequency band.It is difficult to effectively analyze the feature quantity of the fault traveling wave signal by simply using the time domain or frequency domain information of the signal.Therefore,accurate and rapid extraction and analysis of fault traveling wave signal characteristic information is of great significance to transmission circuit protection.The paper firstly analyzes the time-frequency analysis method of signals at domestic and foreign.It is summarized that in the analysis of multi-component,non-stationary signals,compared with other analysis methods,the Wigner Ville distribution is a function of the time and frequency of the signal as an independent variable;When it is used for signal analysis,its time and frequency can be separately selected,thereby avoiding the defect that the time and frequency are mutually restricted;Therefore,the Wigner Ville distribution is used to extract and analyze the waveform feature information of the fault traveling wave signal.The fault traveling wave signal is obtained by using the EMD method to obtain single component signals of different frequency segments;All single-component traveling wave signals are de-aliased,the real traveling wave components are filtered,and the Wigner Ville distribution of each component is obtained;The cross-interference term generated in the Wigner Ville distribution is suppressed,and the Wigner Ville distribution of the original fault traveling wave signal is obtained by linear superposition;The energy spectral density distribution of the Wigner Ville distributed traveling wave signal is obtained,and the time-frequency characteristic information is extracted to realize the accurate analysis of the waveform characteristics of the fault traveling wave signal.Then,based on the method of Wigner Ville distribution,the paper accurately detects and extracts the time feature quantity of the fault traveling wave signal,and realizes fault location under different fault conditions.Finally,based on the unique characteristics of the wide-band transient signal waveform,the Wigner Ville distribution method is used to extract the time-of-flight and frequency-domain features of the fault traveling wave signal,such as rise time,energy amplitude,center frequency and frequency domain.The wave feature quantity database uses the feature quantity correlation matching method to identify the faults in the transmission line and to realize the protection of the transmission line.The simulation results show that the paper method is not affected by noise,and can accurately obtain the waveform characteristic information of the fault traveling wave signal.The positioning algorithm can be used for verification to achieve higher precision fault location;and it is an accurate and reliable transmission line protection method.The method described in the paper can accurately extract and analyze the time-frequency domain waveform characteristic information of the fault traveling wave signal,and can realize the fault location and line protection of the transmission line quickly and accurately,which provides a new idea for the relay protection of the transmission line and is expected to promote the practical application of traveling wave protection.