Thermal decomposition experiment analysis and research on high-voltage cable PVC sheath at different temperatures

Abstract In recent years, the incidence of high-voltage cable fires has gradually increased, posing a serious threat to power supply safety. Polyvinyl Chloride (PVC) is the main component of the high-voltage cable sheath and undergoes thermal decomposition in high-temperature environments such as fires, releasing a variety of gases. To achieve cable fire risk assessment and early warning, it is crucial to accurately grasp its gas generation characteristics. Based on the self-built experimental platform, this study conducted thermal decomposition experiments on the high-voltage cable PVC sheath under air atmosphere at 90 –250 °C. Using an infrared spectrometer, a gas chromatograph, and an ion chromatograph, the thermal decomposition gases were analyzed qualitatively and quantitatively. The research results show that the main gases generated by the thermal decomposition of the high-voltage cable sheath are gases of alkanes, alkenes, acetylenes, and water vapor. This study provides key experimental data support for constructing a characteristic database of high-voltage cable thermal decomposition gases and has important engineering guiding significance for the development of early diagnosis technology based on gas detection for cable fires and the safety prevention and control level of electrical fires.