Multistage Fault State Evolution Analysis and Modeling of Distribution Cables Driven by Signal Analysis and Insulation Degradation Characteristics

Early detection of incipient cable faults is critical for preventing catastrophic power grid failures. While existing diagnostic methods rely on the optimization of classical arc models, their accuracy remains constrained by the impaction of solid insulation degradation on arc characteristics. To resolve this limitation, some 10 kV XLPE cable samples with engineered defects were performed in lab. Electrical signatures synchronized with physicochemical evolution are captured. Through coupling analysis of discharge patterns and insulation pyrolysis processes, a tri-phase fault progression model is established, which are high-frequency intermittent discharge, semi-stable arcing with carbonization path formation, and permanent arcing through fully carbonized channels. Finally, based on PSCAD simulation, the proposed model is utilized to simulate the disturbance signal characteristics of cable faults. Waveform results are compared with field-recorded waveforms to verify the accuracy of the proposed model.