Incipient Fault Detection for Medium Voltage Cables: Considering the Impact of Solid Insulation Degradation on Fault Transient Behavior

Accurately detecting incipient fault states in medium voltage (MV) cables is crucial for preventing sudden cable failures. Existing incipient fault detection methods primarily rely on the nonlinear behavior of arcs inside discharge channels without considering the degradation behavior of solid insulation during fault progression. This limitation hinders the accurate determination of fault stages and makes precise and accurate maintenance difficult. In order to address this problem, a detection scheme based on fault transient characteristics considering cable insulation degradation is designed. First, this article theoretically analyzes the impact of insulation carbonization on fault transient behavior, and incipient fault detection is performed based on the transient variation characteristics of the zero-sequence current waveform. On this basis, a novel approach is developed for diagnosing fault states based on the distortion rate of the zero-sequence current waveform, providing an effective method for accurately detecting incipient fault states in MV cables. Simulations and experiments demonstrate the effectiveness of the proposed method. This study provides a new perspective for future advancements in fault detection methodologies.