Ultra-high voltage direct current transmission line lightning stroke interference recognition method based on voltage relevancy and wavelet transformation transient state energy distribution characteristics

The invention relates to an ultra-high voltage direct current transmission line lightning stroke interference recognition method based on voltage relevancy and wavelet transformation transient state energy distribution characteristics, and belongs to the technical field of power system relay protection. When voltage of an ultra-high voltage direct current transmission line fluctuates, positive voltage and negative voltage of the initial 5ms are monitored; the relevancy between voltage of each electrode and voltage of each axis is calculated, and the lightning stroke interference is recognized according to the relevancy; the recognition of fault classifications is shifted to if the interference is caused by a fault; an additional component of line modal voltage is calculated, and seven dimension decomposition is performed on the additional component by utilizing a db3 wavelet; and the ratio of high frequency energy to low frequency energy is calculated, fault categories are distinguished, and fault protection is performed. According to the method, the signal acquisition time is short, the sample acquisition scale is small, and the voltage relevancy theory is used for recognizing lightning stroke interference and fault, so that the thought is clear, and the accuracy is high; the transient state energy distribution characteristics obtained through wavelet transformation are used for recognizing lightning stroke fault and short circuit fault, and the effect is obvious; and the method is easy to implement and is not easily influenced by system parameters and transition resistance.