Conventional phase difference method pinpoints the PD location by analyzing the phase difference of the primary arriving signals at both terminals in power cable under frequency domain

however it takes the maximum propagation time of pulses as the time window length

which inevitably results in redundant interference in the signal processing and therefore reduces the location accuracy. Based on double-sided phase difference algorithm of optimized time window length

an improved on-line PD location method is proposed. The start and end time points of double-sided pulses are identified when pulse passed the configured amplitude threshold. By means of setting up time margin of rising and falling edge

the removed pulse information before and after are recovered and the optimized time window is then obtained. Afterwards

the matched double-sided pulses captured by the time window calculated before is processed by cross-correlation analysis and Fourier transform

and the defect location from single sample is then determined by phase unwrapping algorithm. Cluster analysis using D-Peak method is adopted to realize the automatic identification of PD clusters from large quantities of PD location results and the horizontal position of cluster center refers to the final PD location. The performance of the proposed technique is evaluated by simulation using ATP-EMTP under noisy environment and experimental test using XLPE cable of 300 m. The results show the improvement of PD location accuracy compared to traditional double-sided phase difference and time-of-arrival approach.