Abstract: During the operation and maintenance of distribution network lines,the difference of characteristic wave identification methods lowers the accuracy of line single-phase grounding fault diagnosis,which fails to meet the working needs of the power system. To this end,a single-phase grounding fault diagnosis method based on traveling wave signal injection is proposed in this paper. The fault characteristic data is obtained through the fault recording device,and the fault waveform characteristic database is constructed. The high voltage pulse signal source is used as the traveling wave signal injection source,and the control loop of the pulse source is analyzed. According to the reflection result of the traveling wave signal,the wavelet transform algorithm is used to identify the line fault characteristic wave. According to the feature extraction results,the Euclidean distance of the feature space is calculated to complete the single-phase grounding fault state diagnosis of distribution network lines. The experimental results show that compared with the current diagnosis methods,the fault diagnosis accuracy of the proposed method is improved by 16% and 28%,which greatly improves the fault diagnosis level of power grid lines.