Determination of U50 breakdown voltage of long air gaps using predictive dynamic model

The aim of this article is to determine the critical breakdown voltage or U50 - corresponding to the 50% probability of breakdown for a single impulse application - of long air-gaps under positive switching impulse voltages, using predictive dynamic model based on equivalent electrical network. This model is similar to that developed previously by our group. It is based on equivalent electrical network, gas discharge theories and physical laws. The investigated electrode gap geometries are more complex than that modeled by others and one can find in literature; the relationships used in literature for the calculation of electric field are analytical relationships for simple geometries, those enabling to better approach the actual geometries. To size more accurately the insulation…