Experimental analysis of artificial contamination flashover characteristics of long insulator strings on 500 kV transmission lines

We experimentally measured the artificial contamination flashover characteristics of 500 kV long insulator strings, since reckoning the flashover voltage of long insulator strings based on data of short insulator strings would result in large deviations. Taking XWP2-160 type two umbrella porcelain insulators as samples, we obtained the artificial contamination flashover voltages of hang single-string insulators under different equivalent salt deposit density (ESDD), different non-soluble deposit density (NSDD), and uneven deposition filthy through experiments. Moreover, we calculated the effective coefficient of creepage distance for this type of insulator string according to the experimental results, and compared the results from tests using string insulators of V type, inverted-V type and single hang type to get the correction coefficient for abnormal types of insulator strings. Experimental results reveal that, the flashover voltage of XWP2-160 insulator string is negatively correlated to ESDD and NSDD; the effective coefficient of creepage distance for the single hang type is 0.78; the flashover voltage of a single insulator from a V type or inverted-V type string is slightly higher than that from the single hang type strings; the string-structure correction coefficients of V type and inverted-V type are 1.08 and 1.15, respectively. The results can be referred by the anti-contamination works for operation of the long insulator strings on 500 kV transmission lines.