A fundamental study on electrical insulation of N{sub}2SF{sub}6 gas-insulated electric power apparatus

摘要

In this paper, we carried out a case study on fundamental insulation design for the application of N{sub}2/SF{sub}6 gas mixtures to a 275-ky gas-insulated busbar. First, we investigated the impulse ratio in N{sub}2/SF{sub}6 gas mixtures and point out that the insulation design might be based on the negative switching impulse voltage in the case of lower S{sub}F6 content. Second, we estimated the tank diameter and SF{sub}6 gas amount with consideration of the electric field strength on conductor surface and temperature rise in gas mixtures. We clarified that the tank diameter at the lower SF{sub}6 content is mainly determined by the electric field strength on the conductor surface and quantified the optimum gas pressure and SF{sub}6 content for a target reduction of SF{sub}6 gas amount.