Study on the Ageing Characteristics of Silicone Rubber for Composite Insulators under Multi-Factor Coupling Effects

Abstract

Due to long-term exposure to high electrical field strength, heavy loads, and the complex climatic conditions in tropical coastal areas of China, widespread abnormal heating phenomena often occur in the operation of composite insulators in power transmission lines, posing a threat to the safe and stable operation of the power system. To study the ageing process of the silicone rubber sheath of composite insulators in the high-field, high-humidity, high-temperature, and high-salt-density environments along the coastal regions, this paper establishes a humidity–heat–electricity–salt spray accelerated ageing test platform and conducts ageing tests on silicone rubber materials for composite insulators under the coupled effect of multiple factors. The ageing characteristics of silicone rubber materials are analyzed using scanning electron microscopy, Fourier infrared spectroscopy, thermogravimetric analysis, and other methods. The results show that the coupled ageing factors have an impact on the surface morphology of silicone rubber. The continuous depolymerization of PDMS molecular chains leads to a decrease in the content of groups related to the hydrophobicity of the material, resulting in a deterioration of its hydrophobicity. Moreover, the degradation of silicone rubber materials and the enhanced moisture absorption capacity lead to an increase in the dielectric loss tangent of the saturated moisture-absorbing medium, thereby causing abnormal heating of the sheath at the end of the composite insulator. The research findings of this study are of significant reference value for revealing the degradation mechanism of composite insulator silicone rubber sheaths in tropical island environments and improving the service life of composite insulators.

Study on the Mechanism Effect of Bending Loads on the Decay-like Degradation of Composite Insulator GFRP Core Rod

“…Samples were regularly taken from deionized water for weigh then quickly immersed back into ionized water to continue the moisture absorp The weighing results were taken as the average of the 3 samples, and the pro repeated until the weight of the samples no longer changed, that is, when they the saturation and moisture absorption level. The formula for calculating the absorption rate Mt of the sample is as follows [28]:…”

“…The weighing results were taken as the average of the 3 samples, and the process was repeated until the weight of the samples no longer changed, that is, when they reached the saturation and moisture absorption level. The formula for calculating the moisture absorption rate M t of the sample is as follows [28]:…”

Analysis of Aging Characteristics of Umbrella Skirts of Composite Insulators Operating under the Influence of a Wind and Sand Environment in South Xinjiang

“…Silicone rubber composite insulators have been widely used in high voltage transmission lines because of their good hydrophobic and water-repellent mobility, excellent anti-fouling flashover performance, low cost, light weight, and easy installation, etc. [1]. The main structure of the composite insulator is composed of a high-temperature vulcanized silicone rubber umbrella skirt and sheath, glass steel core rod, pressure balancing ring, and end fittings.…”