Research of cycloaliphatic epoxy resin and silicone rubber composite insulator interface based on four‐electrode system and temperature rise model

Abstract

Interface degradation between mandrel and sheath can cause a decrease in insulation performance and mechanical strength of composite insulators. In this study, the interface ageing properties of cycloaliphatic epoxy resin and silicone rubber composite insulator were compared. A water diffusion test was adopted to simulate the composite insulator ageing in a hot and humid environment. A four‐electrode system was built to detect leakage current at different locations (mandrel, sheath and interface), which is an important basis for evaluating insulator performance. The ageing degree of insulator could be quantitatively characterised by leakage current change. It was found that the infiltrated moisture had a great effect on insulation performance. Based on the water absorption test result, the interface performance of two insulators was mainly influenced by their sheath sealing quality. As an auxiliary evaluation method, temperature rise during the test was recorded using an infrared camera. The experiment results showed that interface degradation was the main factor for the insulation performance decrease of silicone rubber composite insulators. However, insulation level reduction of the cycloaliphatic epoxy resin was caused by the wet sheath. In addition, a model for temperature rise of cycloaliphatic epoxy resin insulators was proposed based on good correspondence between sheath material and insulation. The model incorporated multiple processes such as ageing and heating of insulators, and it can predict the early temperature rise well.

A review of the effect of hydrothermal aging on the mechanical properties of 2D fiber‐reinforced resin matrix composites

“…When a large number of cracks appear in the material, its mechanical properties deteriorate, and the glass transition temperature decreases, ultimately leading to the failure of the material 47 . The water adsorption behavior of epoxy resin at different temperatures conforms to the Langmuir EXT1 isothermal adsorption model, and the water penetration rate is inversely proportional to the thickness 48 . At the same temperature, it follows Fickian diffusion, 49 and elevated temperature increases molecules' mobility while reducing polymer's load‐bearing capacity.…”

“…47 The water adsorption behavior of epoxy resin at different temperatures conforms to the Langmuir EXT1 isothermal adsorption model, and the water penetration rate is inversely proportional to the thickness. 48 At the same temperature, it follows Fickian diffusion, 49 and elevated temperature increases molecules' mobility while reducing polymer's load-bearing capacity. After hydrothermal aging of epoxy resin, many tiny pores appear on the surface and cut the surface.…”

Influence characteristics of water penetration on fibre‐reinforced polymer/rigid polyurethane foam interface of the composite cross‐arm considering natural ageing

“…Several studies have depicted that the interface leakage current can effectively reflect the electrical properties of the sheath-core interface of composite insulators [7,16,23]. This study developed a four-electrode current test platform (Supporting Information S1: Figure A3) to measure the leakage current at the FRP/RPUF interface.…”

“…Burnham et al [15] conducted case studies on several in-service faults of composite insulators and believed that moisture might contact the sheath-core interface through the composite insulator's end, defect, or sheath diffusion. Wang et al [16] simulated the ageing process of composite insulators in hygrothermal ageing using a boiling experiment and characterised the interface insulation of the sheath-core using a leakage current test. The results show that interface degradation is the main factor responsible for the decrease in insulator insulation performance.…”

“…Wang et al. [16] simulated the ageing process of composite insulators in hygrothermal ageing using a boiling experiment and characterised the interface insulation of the sheath‐core using a leakage current test. The results show that interface degradation is the main factor responsible for the decrease in insulator insulation performance.…”