Electrical breakdown properties of low density polyethylene under DC voltage

The development of high voltage DC power cable is far lagging behind that of AC power cable partly due to the breakdown properties of DC cable insulation under the influence of multiple factors such as space charge and temperature. This paper presents an experimental research on electrical breakdown properties of LDPE at various temperatures to investigate the properties of DC cable insulation. A thermal aging chamber was designed for the breakdown experiment of LDPE at different levels of temperature. The breakdown experiments of LDPE were carried out and thus the influence of temperature and voltage type on the breakdown properties of LDPE was obtained. The results show that temperature has significant influence on the breakdown field strength of LDPE under DC voltage. The dispersion of breakdown field strength becomes bigger with the increase of temperature. In contrast, the influence of temperature on breakdown strength of LDPE insulation under AC voltage is relatively small.