Difference Analysis of Lightning Strike Flashover Criterion for 110 kV Insulator with Grading Ring

The lightning impulse flashover criterion of insulators is one of the important simulation models to evaluate the lightning resistance performance of transmission lines. The actual flashover characteristics of insulators with different shapes have certain differences. At the same time, when lightning strikes back, the standard insulator flashover criterion based on lightning shock has certain limitations. In this paper, positive standard lightning shock test and positive short tail lightning shock test were carried out respectively in plain and high altitude areas for the composite insulators of 110 kV line without voltage grading ring, voltage grading ring at high voltage end and voltage grading ring at both ends, and the influence of different lightning shocks on flashover characteristics was compared. The flashover characteristics and the flashover criterion of lightning strike under the action of lightning current are studied. Then, according to the test data of 110 kV insulator, the simulation model of different flashover criteria is carried out, and the lightning resistance level of different flashover criteria is compared and analyzed, and the difference of flashover characteristics is obtained when different voltage grading rings are installed.