Implementation of a discharge propagation model using an electric field map: an attempt toward a design tool for high-voltage overhead insulation

This paper presents the first step in developing a tool which would be able to predict the breakdown voltage of air insulation under a positive switch ing impulse. The discharge model uses a map of the Laplacian potential and the electric field computed by an electric field software. The model is bas ed on the previous work of different authors who have studied the positive discharge theoretically as well as experimentally. After a presentation of the different aspects of the model some results are analysed. These results concern classical rod-plane configurations for which valuable and accurate measurements are available. The analysis points out some weaknesses of the model that will have to be corrected to treat realistic configurations. Ne vertheless, as the modification of only one parameter with the gap distance permits us to compute U-50 to an acceptable accuracy, the model could alre ady be used to compare two insulating structures of the same type.