Investigation of the Compatibility between Mechanical Fixing Tapes and Impregnation Fluid of Power Capacitors

The potential compatibility risks between the impregnation fluid and mechanical fixing materials of power capacitors may cause the distortion of internal packages, which can evolve into the insulation failure and even explosions. However, research focused on this area was rare to see. This article proposed a scientific research on the compatibility experiment between adhesive tapes as well as packing tapes with the impregnant mono-dibenzyl toluene (M/DBT). The test duration varied from 168 to 672 hours, and the examinations of both the fluid and solid materials were carried out. Few influences on the fluid were found since the breakdown voltage of impregnant remained at the same level around 50 kV for 4 weeks. For the packing tapes, elongation at break and tensile strength increased in the first week and then decreased slowly, and few changes of microstructure were shown. For the adhesive tapes, the tensile strength increased in the first week and then slowly decreased, while the elongation at break slightly declined. The experiment results indicated good compatibility between capacitor impregnation fluid and mechanical fixing tapes, and meanwhile provided theoretical and experimental basis for the compatibility evaluation, which contributed to the design and operation of liquid-impregnated capacitors.