A study of natural contamination characteristics of insulators on ±500 kV Gezhouba-Nanqiao HVDC transmission lines

Abstract

To study the natural contamination characteristics of insulators on DC lines， measurement points are set between sections Jiaxing and Huzhou of ±500 kV Gezhouba-Nanqiao HVDC transmission lines to carry out natural contamination tests. The equivalent salt deposit density （ESDD） and non-soluble deposit density （NSDD） of insulators are obtained through tests. Also， the effect of electric field and shed shapes on the contamination characteristics of insulators is studied. The results show that the bell-shaped insulators are more susceptible to contamination in contrast to double-shed ones； the ESDD and NSDD of a bell-shaped insulator are 1.73 and 1.54 times respectively as much as those of the double-shed one； the NSDD/ESDD ratio of a double-shed insulator is slightly smaller than that of a bell-shaped one， and the contamination unevenness of a double-shed insulator is far smaller than that of the latter. Finally， a method for calculating the effective utilization coefficient of insulator creepage distance considering contamination unevenness and NSDD is proposed， and the effective utilization coefficients of the creepage distances of XZWP-160 insulators under different contamination levels are calculated. The research results can be a beneficial reference for line flashover prevention.

Keywords

• natural contamination
• dc transmission
• energy coefficient
• nsdd/esdd ratio
• contamination unevenness
• effective utilization coefficient of creepage distance