A study on the effect of temperature rise on the effectiveness of detecting typical defects in rubber-impregnated paper sleeves

Abstract

Epoxy rubber-impregnated paper casing has the advantages of stable electrical performance, explosion-proof function, small volume, lightweight, etc., and has been widely used in transformer casing and through-wall casing. However, its manufacturing process is complex, which makes it easy to produce defects in the production process, and it is difficult to detect certain defects in the test at room temperature. To study the partial discharge and dielectric loss characteristics of typical defects of rubber-impregnated paper bushings after temperature rise, we designed and prepared defective bushings with moisture, metal particles, and core cracks, and measured the partial discharge pattern and dielectric loss factor of the bushings after they were heated to a certain temperature. The results show that the core crack defective casing discharge increases more after heating, followed by moisture defective casing, and metal particles defective casing has the smallest impact, indicating that for the temperature rise test in the thermal state of the core crack, moisture defective casing detection effect is better. The results of the study can provide certain references and guidance for the factory inspection and troubleshooting of rubber-impregnated paper casing.