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Reference: ISH2015_241

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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 structures, it is necessary to take into account the actual geometry of these structures. For that purpose, we developed a model of discharge for a rod-rod gap. Then we determine the U50 voltage using the developed model and the up and down method. The simulated results are compared to experimental data and to those provided by empirical formula.

File Size: 707,7 KB

Year: 2015

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