Estimation of Leader Velocity During Insulator String Flashover Process

The leader progression model (LPM) is commonly used to simulate the insulator string flashover process because it considers the physical process of discharge. In this model, the leader velocity is a very important physical quantity. In this paper, experiments were carried out to study the flashover characteristics of composite insulator strings under a short tail lightning impulse, in which the high-speed images and discharge current were recorded simultaneously. In addition to calculating the leader velocity from high-speed images, this paper proposes a method for estimating the average leader velocity based on the discharge current. The accuracy of the proposed method is verified by comparing the results with different methods. The relationship between the leader velocity and the amplitude of the applied voltage during the insulator string flashover is obtained accordingly. Experimental results in this paper will help to further validate and refine the LPM.