Influence of surface sand blasting treatment on vacuum surface flashover characteristics of PMMA insulator

Surface roughening treatment on insulators is an important way to improve their vacuum surface flashover characteristics. However, flashover voltages of the insulators with the same roughness show big deviation because of the poor uniformity of the surface rough structure and bad repeatability of the surface roughening method. To improve the uniformity of the surface roughening and the stability of the voltage-withstanding of the vacuum insulators, sand blasting roughening treatment on the surface of the cylindrical PMMA insulators was studied. First of all, the cylindrical insulators were sprayed on the rotating platform. With the collisions of the spherical micro SiO2 particles carried by the high-speed airflow, rough structure was fabricated on the surface. After the corrosion of the HF acid, residual SiO2 particles were removed, leaving homogeneous rough structure on the surface. The changes of the surface morphology were studied by Scanning Electron Microscope and the surface roughness of the treated insulators was tested on the surface roughness meter. Surface flashover characteristics of the sand-sprayed PMMA specimens were tested on the short-pulsed high-voltage platform. The test results indicated that homogeneously rough surface was prepared by the sand blasting treatment and the surface flashover voltages of the treated insulators were improved steadily. Compared with the untreated PMMA specimens, flashover voltages of the sand blasted insulators were improved approximately 80%.