Hygro-Thermal Coupling in Cable Insulation and Its Effects on Conductivity Variation and Temperature Distribution

In power transmission systems, prolonged use can cause aging of cable insulation materials, specifically Cross-linked Polyethylene (XLPE). This aging can result in overheating hotspots within the cable, potentially leading to severe safety incidents. This study investigates the effect of environmental humidity under high-temperature and moist conditions on the thermal conductivity of XLPE cables and analyzes its impact on cable temperature distribution. Theoretical analysis explored the aging mechanisms of XLPE in moist environments, focusing on how environmental factors affect thermal conductivity changes. A dynamic simulation model predicts the specific impacts of these changes on cable operating temperatures. Simulation results show that moist environments significantly accelerate XLPE aging, notably altering its thermal conductivity. These changes directly affect the temperature distribution and operational safety of the cable. The simulation data clearly demonstrated the temperature distribution trends, effectively predicting the overheating hotspot locations in the XLPE. This enhances early warning and risk management capabilities, thereby improving the overall reliability and safety of the power system. Furthermore, experimental validation was performed concurrently in this study. The experimental findings provided additional confirmation of the simulation analysis results, demonstrating that cables subjected to prolonged exposure to humid environments exhibited significantly accelerated temperature rise rates and elevated steady-state temperatures. These results underscore the critical importance of optimizing temperature monitoring protocols and maintenance strategies in practical engineering applications to ensure the safe and reliable operation of cable systems in the future. These findings provide a scientific basis for predicting cable performance in extreme environments and offer insights for optimizing cable design, maintenance strategies, and overall system safety and efficiency.