Research on insulation condition of damp cable termination under different temperatures

Abstract

In recent years, medium voltage power cable has been widely used in the transmission and distribution network. However, the fault rate of cable accessories has increased year by year. During the fabrication and operation of cable accessories, the moisture can easily enter into cable accessories and make it damp, which will influence the insulation condition and lead to the failure of cable. In this paper, test platform of cable whose temperature was risen by load, was built, and four cables with damp cable terminations were selected. The insulation resistance and dielectric loss tangent under different temperatures were measured to study the variation law of insulation resistance and dielectric loss tangent influenced by temperature and damp. There was evaporation of moisture during the test. With the rise of temperature, the damp degree of termination was mitigated, and the insulation conditions improved, due to the evaporation of moisture. As the temperature continued to rise, the effect of temperature on the insulating materials gradually become the main factor affecting of insulation state, deteriorated.