Optimization of Cable High-Frequency Model Based on Partial Discharge Propagation Characteristics

Partial discharge (PD) detection serves as a critical technology for identifying and locating defects in power cable insulation. However, technical challenges arise from signal attenuation and dispersion phenomena during partial discharge pulse propagation along power cables. These effects stem from both the inherent single-core multilayer cable structure and diverse grounding configurations of metallic shielding layers, leading to notable difficulties in achieving precise partial discharge identification and location. To overcome this limitation, this study presents an enhanced cable parameter modeling methodology. The approach improves conventional distributed parameter models through rationalized analytical procedures. The developed model further establishes an equivalent <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Gamma$</tex>-type circuit representation for 35 kV power cables. Leveraging this circuit configuration, we systematically investigate propagation characteristics of four partial discharge types: internal discharge, surface discharge, corona discharge, and floating discharge. Based on simulation and experimental results, it can be deduced that high-frequency partial discharge pulses exhibit faster attenuation rates within cable transmission systems. In addition, signal amplitude attenuation and pulse broadening phenomena are consistently observed across all partial discharge types due to combined dispersion and attenuation effects. Moreover, the proposed cable frequencyvariation model is able to reflect the propagation characteristics of various local discharge pulses in cables. These results provide theoretical foundations and practical references for implementing accurate partial discharge identification, localization, and cable fault diagnosis strategies.