Potential distribution analysis of Y-type insulators in UHV 1000kV double circuit transmission lines

As extremely important insulation support, insulators play a significant role in the transmission lines construction project. That the type of insulators varies with the environment condition can control the corridor width effectively. For now insulators of the II-type and the V-type are common used in the in-service transmission lines. By using the Y-type insulator, the corridor width of transmission line is consistent with that using the V-type insulator, and by choosing a reasonable proportion of the II-type string and the V-type string, the dimensions of the tower can be reduced, which provides both safety performance and better economic efficiency. Utilizing the finite element method, this article researched the potential and electric field distribution of the Y-type insulators string in UHV 1000kV AC double circuit transmission line, and compared to that of the II-type insulator and the V-type insulator. The voltage value and percentage of the II-type string and the V-type string of the Y-type insulators of varying length were calculated afterwards. According to the calculated result and experimental verification, a reasonable selection to balance the economic efficiency and operation reliability has been made. The results enjoy very important practical engineering significance for construction of UHV transmission lines and improving reliability of UHV AC transmission lines.