Time‐Domain Computation of Propagation Characteristics of Partial Discharge in Cross‐Linked Polyethylene High‐Voltage Cable Incorporating Modified Frequency‐Dependent Parameters

The propagation characteristics of partial discharge (PD) in cables impact PD detection sensitivity, defect localisation accuracy and defect severity evaluation. Currently, the effects of semiconducting materials' frequency‐dependent properties and corrugated aluminium sheath structures on PD signal propagation in high‐voltage (HV) cables remain unexplored. This paper introduces a time‐domain computing model to address these issues. The geometric mean radius is used to modify the impedance and admittance per unit length of HV cables with corrugated aluminium sheaths. The complex permittivity spectrums of the semiconducting shielding layer and water‐blocking buffer layer are tested, and their Cole–Cole model parameters are fitted. Utilising the vector fitting algorithm, the impedance and admittance per unit length of the cable, incorporating the frequency‐dependent parameters of the semiconducting layers and the modified parameters of the corrugated aluminium sheath, are computed. Multiple Γ sections are cascaded to calculate the time‐domain waveform of PD signals using state‐space equations and sparse matrices. This study simulates and analyses double exponential, damped oscillating and Gaussian PD signals, examining their time‐domain characteristics, spectrum and highest effective frequency over various propagation distances. Results are compared with the Alternative Transients Program cable model and the state‐space equation model with classic parameters. Finally, tests are conducted on a 10‐m HV cable in the laboratory to verify the proposed algorithm.