Thermal mechanical performance test on suspended insulators for transmission line

Abstract

This study described some basic performance tests and accelerated ageing test by cool-heat cycling methods and thermal mechanical performance test methods on alumina porcelain insulators (new and aged) used for transmission lines in Korea. There were no failures in electrical and mechanical performance tests such as high voltage strength, flashover voltage, impact strength, etc. in any of the samples. However in the case of accelerated ageing tests above 90 /spl deg/C temperature gradient, fracture phenomena occurred by a thermal shock in the aged samples with low aluminous porcelain body. It was found that sample A was more severely aged than other samples. According to results of the HRB test and microstructural analysis, it was reasoned that insulator bodies with the matrix reinforced with alumina crystalline phase have advantages in the suppression of crack propagation. Cool-heat aging and mechanical thermal aging tests show that a temperature gradient is more effective for acceleration of the aging than variation in the number of cycles.