Parallel Multigap Flashover Probability

This study aims to make clear the air-gap flashover probabilities for positive long-front impulse voltages, especially in the extremely small probability domain, by using the flashover characteristics of the parallel multigap, which consists of 20 3- meter rod-rod gap pairs. The flashover probability relation between single gap and multigap will be shown by a simple equation. On the basis of this relation, air-gap flashover probability with respect to applied voltage will be shown to follow normal distribution down to V50 percent ¿3.95¿in the extremely small flashover domain. The calibration of the influence of weather conditions on the 50- percent flashover voltage and the standard deviation was obtained as a result of a series of experiments extending through four seasons. A method of calculating flashover probability on transmission lines for switching surges is shown as an example of the application of multigap flashover characteristics.