A Comparative Study on Contamination Deposited Characteristics of 800kV DC Line Insulators

This report describes the natural contamination test results of 800kV line insulators at high altitudes. Natural exposure tests with -816kV DC voltage energization were carried out at National Engineering Laboratory for UHV Engineering Technology (Kunming).The results showed that the strain type and V-type insulator strings show a lighter pollution and the insulators with a better aerodynamic shed shape show a better contamination deposited characteristic. Also the ratios of contamination on top surface to that on bottom surface in terms of the equivalent salt deposit density (ESDD) and the nonsoluble deposit density (NSDD) were influenced by the insulator shed shapes and the string types. The ESDD and the NSDD along the insulator strings presented decreasing trend from the earth side to the line side.