Effect of inverted T arrangement on AC pollution flashover characteristics of insulator strings

Abstract

The arrangement of insulator strings has an effect on its pollution flashover characteristics. A new arrangement of insulator strings, inverted T-type arrangement, is proposed in this study. The electric field distribution is simulated and the pollution flashover characteristics are tested in an artificial climate chamber. The test results indicate that the inverted T-type arrangement can greatly improve the flashover voltage of polluted insulator strings, the ‘7 + 2’ inverted T-type arrangement can increase the flashover voltage of each insulator by 8.5% on average, and the ‘3 + 3’ inverted T-type arrangement can increase the flashover voltage of each insulator by 13.4%. The discharge process is different from that of the normal suspension string when the insulator string is inverted T-shaped, i.e. a local arc is produced at the low voltage end of the insulator string and develops downward along the suspension part. While as for the horizontal tension string parts, it is difficult to generate arc during discharge development.