Recognition of HVDC Transmission Line Lightning Strike Interference Based on HHT Algorithm

According to the shortcomings of the current traveling wave ranging method and the problems existing in the wave head measurement algorithm, by analyzing the variation of traveling wave velocity with frequency, we can deduce the frequency region coverage of the wave velocity stabilization time, so as to overcome the negative impact of the wave velocity variation on the ranging accuracy conclusion. In the further study of high-voltage direct current transmission line fault traveling wave arrival time and traveling wave must be based on the instantaneous amplitude correlation theory, analyzes the instantaneous amplitude directly affects the mechanism of the traveling wave ranging, and gives a transmission line fault distance scheme based on the instantaneous amplitude, according to using the Hilbert huang transform (HHT), an iterative fashion, low voltage high frequency transmission failure is established According to the time-lapse diagram, the traveling wave head time is determined to be the instantaneous amplitude at a certain time, so as to establish the fault distance calculation of HVDC transmission line. A lightning point location method for transmission line based on Hilbert Huang transform (HHT) is proposed. When OPGW is struck by lightning, the transmitted light in its internal communication fiber generates polarization state mutation signal due to Faraday effect. Firstly, the polarization state signal is denoised, and then the polarization state signal after noise reduction is Hilbert Huang transformed and processed to obtain the spectrum of amplitude and frequency changing with time, Thus, the time when the polarization state mutation signal reaches the polarization state demodulation equipment is obtained to locate the lightning point.