Comparison of Suppression Effects of Various Coating Schemes on Surface Charge Accumulation for DC GIS Insulator
Di Lu, Yu Gao, Pinhao Huang, Tao Han, Boxue DuABSTRACT
The suppression of surface charge accumulation on insulators is considered a crucial issue in improving the insulation safety of DC gas‐insulated switchgear (GIS). In this work, the performance of various coating schemes in suppressing charge accumulation on DC GIS insulators is assessed. Nano‐graphene (GR), nano‐Al 2 O 3 and nano‐SiC were selected as fillers and dispersed in epoxy for the preparation of coatings with different conductivities. Coatings were deposited on the insulator in two schemes: single‐coating and zoning‐coating schemes. Standard deviation and information entropy were applied to evaluate the irregularity of charge distribution. Test results showed that compared with the uncoated insulator, the maximum decrease in charge density on single‐coating samples reached 68.21% and 79.65% on concave and convex surfaces. For the insulator with the zoning‐coating scheme, the maximum decrease in charge density reached 77.58% and 84.18%, respectively. Besides, the irregularity of charge distribution on coated samples also decreased. It is suggested that the modification of the electrical parameters on the insulator via the zoning‐coating scheme can be a more efficient method for suppressing charge accumulation on the DC GIS insulator.