Repeated impulse aging of oil-polypropylene insulation

Abstract

Repeated impulse voltage has long been considered to affect the insulation property of power equipment, which is called accumulative effect. This phenomenon is widely studied on oil paper insulation but rarely on oil polypropylene film insulation, which is widely used in power capacitors and other equipment. Therefore, the accumulative effect of repeated impulse on oil polypropylene insulation is studied in this work. First, a repeated impulse accumulating test platform was set up and the accumulation characteristics of oil polypropylene insulation with repeated impulses were tested and analyzed. Next, the residual breakdown voltage, surface morphology and gas composition dissolved in the oil in different aging levels were tested. The results indicated that the OPF insulation residual breakdown voltage decreased and the film surface roughness increased when subjected to the repeated impulses. The dissolved gas contents changed along with the impulse accumulation aging. Lastly, the possible mechanisms of the accumulative effect in oil polypropylene insulation are discussed based on the test results.