Study on artificial multi-stress ageing characteristics of composite insulators

摘要

In recent years, abnormal heating of composite insulators has become a serious problem, especially in the coastal areas of southern China. In this paper, an improved multi-stress aging test for composite insulators was proposed based on the environment of the coastal areas in southern China, and 5000 h aging test was carried out. The test results showed that the wet flash-over voltage decreased linearly, while the hydrophobicity of the shed showed a nonlinear aging characteristics, whose change rate increased gradually. The multi-stress aging condition had little influence on shed hardness for the change of the shed hardness remained within 1%. The aged composite insulator showed significant temperature rise and the temperature rise concentrated on the high voltage end at high humidity, while it showed little temperature rise at low humidity. The dielectric loss of silicone rubber after moisture absorption was tested. It could effectively reflect the moisture absorption characteristics and the dielectric properties of silicone rubber after moisture absorption, and was closely related to the wet flash-over voltage and temperature rise of the composite insulator. The dielectric loss of silicone rubber after moisture absorption could be used as a new method to evaluate the operating state of composite insulators.