Microstructure Evolution Study of the Field-Serviced Silicone Rubber Insulator via X-Ray Micro-CT Imaging

Area of Science:

• Materials Science
• Electrical Engineering
• Polymer Science

Background:

• Composite silicone rubber insulators are critical for overhead power lines.
• Aging significantly degrades insulator performance and lifespan.
• Limited understanding of 3D microstructural changes during insulator aging.

Purpose of the Study:

• To investigate the 3D microstructural evolution of aged composite silicone rubber insulators.
• To compare the microstructure of fresh and field-serviced insulators.
• To provide insights for enhancing insulator long-term reliability.

Main Methods:

• X-ray micro-computed tomography (X-ray micro-CT) was used for 3D microstructure characterization.
• Comparison between a fresh insulator and one with 10 years of outdoor service.
• Quantitative analysis of pore characteristics, porosity, and crack formation.

Main Results:

• Aging led to a decrease in pore number but an increase in pore size and overall porosity.
• New cracks (100-900 μm) were observed in the field-serviced insulator.
• The aging depth was found to be less than 300 μm, with pore shape largely unchanged.

Conclusions:

• Aging significantly alters the 3D microstructure of silicone rubber insulators.
• X-ray micro-CT effectively visualizes aging-induced microstructural changes.
• Understanding these changes is key to improving the durability and service life of insulators.