Evaluation of aging process of silicone rubber composite insulators with photothermal radiometry

Abstract

Silicone rubber composite insulators are increasingly used in high-voltage power transmission and distribution grids. However, the aging of composite insulators is a serious safety issue of power systems. Understanding the aging mechanism of composite insulators is therefore of great importance. In this paper, a 3D photothermal radiometry (PTR) is employed to determine the thermal and absorption properties of silicone rubber composite insulators aged in natural environment. A 3D PTR model was developed to extract precisely the thermal diffusivity and absorption coefficients of the composite insulators. In this PTR model both surface and bulk absorptions were accounted for by taking into consideration the fact that a surface absorption of aged composite insulators would be created and changed by surface crazing, chalking, and contamination during aging process. By multi-parameter fitting the measured modulation frequency dependences of PTR amplitude and phase to this 3D PTR model, the thermal diffusivity, surface absorption, as well as bulk absorption coefficient of the composite insulators were extracted simultaneously. The comparisons between the thermal diffusivities, absorption characteristics of fresh and aged composite insulators indicated that aging caused significant decrease of thermal diffusivity and substantial increase of absorption of composite insulators, and the thermal diffusivity and absorption changes were aging level dependent. These experimental results demonstrated that both thermal and absorption properties may be useful parameters for evaluating the aging level and understanding the aging mechanism of silicone rubber composite insulators.

Investigations of the improved performances of silicone rubber in the presence of black titanium

“…3. After aging at 250 °C for 72 h, the retention rate of elongation at break of SR‐0 without the addition of BT was markedly reduced to 5% of the original elongation at break, suggesting a large number of molecular main chains in SR were broken and exhibited brittle behavior after high‐temperature aging 27,28 . In the case of SR‐0.5, the retention rate of elongation at break decreased to 15%, which showed a better aging behavior than SR‐0.…”

“…Heat aging resistance is one of the most important properties of SR‐based heat‐conducting devices 26,27 . Therefore, the mechanical properties of the SR composites with different BT contents after aging at 250 °C were determined to evaluate the heat resistance of the SR composites.…”

Optimized Unilateral Magnetic Resonance Sensor with Constant Gradient and Its Applications on Composite Insulators

“…1, composite insulators have gained popularity in electric power systems because of their lightweight, good anti-fouling and flash performance, and high mechanical strength. However, the prolonged exposure of composite insulators to electric fields, ultraviolet light, acid rain, and fouling leads to their aging and deterioration of electrical and mechanical properties, which potentially jeopardizes the power supply reliability of the power grid [2]. Therefore, testing the performance of composite insulators, assessing the degree of insulator aging, determining whether replacements are necessary, troubleshooting the power grid, and improving the efficiency of equipment condition maintenance are critical to ensuring the safe operation of the power system [3,4].…”

Performance Evaluation of 230 kV Polymer Insulators in the Coastal Area of Saudi Arabia

“…Surface aging may take the form of a whitish deposit on the surface during weathering. This behavior is termed as 'Chalking' [14]. Some weathering polymers induce a surface hardening, which becomes brittle, usually in a very small thickness (0.01mm to 0.1mm) and show micro-fractures like treeing.…”