Study on pyrolysis characteristics of polyethylene outer sheath of 110kV power cable under overheating defect

The polyethylene (PE) outer sheath of power cable is easy to burn due to cable defect. Therefore, it is necessary to explore the pyrolysis characteristics of PE outer sheath of power cable to construct cable fire early warning technology. In this paper, the pyrolysis experiment of PE outer sheath of typical 110kV power cable in was done via thermogravimetry infrared spectrometer, the thermogravimetric analysis curve and differential thermogravimetric analysis curve of PE outer sheath under five different temperature rise conditions were obtained. The results shown that the mass fraction of the PE outer sheath in the initial stage will increase at the rates of 40, 60 and 80°C /min, and even exceed 100%. However, after the initial stage, the sample mass at the five temperature rise rates will decrease with the progress of the experiment. The mass loss rate only had one peak near 450°C under 10°C/min. However, The mass loss rate only had two peaks near 300°C and 450 °C under other four temperature rise rates.