Corona cloud model predictions of switching surge flashover voltages vs. electrode geometry

Calculated positive switching surge flashover voltages for a wide range of electrode geometries are presented and compared with experiment in this paper. The results are presented as flashover voltages relative to rod-plane gap flashover voltages, or gap factors. Calculated and experimental results are in good agreement. The theoretical model used assumes a conducting corona cloud with an experimentally observed shape. The calculations show that corona cloud growth becomes unstable when the corona cloud has crossed about two-thirds of the interelectrode gap. The simplicity of the corona cloud model and the use of the charge simulation method for the required electric field calculations permit flashover voltage estimates for complex, three-dimensional electrode geometries.