Reappearance of Typical Characteristics of FRP Core Rods in the Decay-Like Fracture Insulator

In this paper, an artificial accelerated aging platform of Fiber Reinforced Plastic (FRP) core rod with various aging conditions, including high temperature, acid corrosion and high electric field strength, is presented. Based on that, the typical degradation characteristic of FRP core rods in decay-like fracture insulators are simulated and verified. A thermal infrared imager is used to detect the temperature rise when the AC voltage is applied. The results show that the temperature of the FRP specimens under multiple stresses is significantly increased up to 61 °C (177%) compared with the specimen under single aging stress (22 °C). Moreover, Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and Thermal Gravimetric Analysis (TGA) are applied to study the physicochemical properties of the aging FRP specimen and the reaction occurred in the degradation process and the influence mechanism among different aging factors. The results show that the epoxy resin matrix is eroded by water and nitric acid. In the presence of a high electric field, the epoxy resin matrix is further degraded and evaporated. Then the interface between the epoxy resin and the glass fiber separates and develops, accompanied by ion-exchange and hydrolysis process. With the development of the degradation process of FRP core rod, obvious carbonized channel can be detected. Finally, electric erosion puncture occurs and breakdown happens. Compared with the FRP core rod extracted from the decay-like fractured composite insulators, the artificial accelerated aging sample shows the similar change trend on physicochemical properties. This work can provide theoretical support for the FRP core rod degradation mechanism and life predicting of high voltage composite insulators or other actual operation environment.