Improved Double-Sided Partial Discharge Location Method for High-Voltage Cables via Pulse-Injected Time Synchronization and Variational Mode Decomposition

Partial discharge (PD) diagnosis is a crucial technique for assessing the insulation condition of high-voltage (HV) cables. The double-sided traveling wave method is effective for online PD localization on HV cables. However, the PD localization accuracy is limited by three main factors: inaccurate time synchronization among sensors, imprecise pulse propagation velocity, and noise interference. To address these issues, a bidirectional pulse-injected time synchronization method (BPTSM) is proposed to correct the timing bases of detectors and assess the pulse propagation velocity along cables independently of cable parameters. Furthermore, a denoising method combining the short-time Fourier transform (STFT) and variational mode decomposition (VMD) is designed to enhance the robustness of the system to high-intensity noise. Finally, an integrated PD detector with pulse injection and signal detection functions and switchable measurement ranges is designed to improve detection sensitivity. To validate the effectiveness of the proposed method, a portable system is developed, and experiments are conducted on both a 10-kV cable in the laboratory and a 110-kV cable in the field. The experimental results confirm that the proposed method enhances the accuracy of PD localization.