Critical condition of DC flashover on a circular sector model

In order to find the electrical size which determined the critical condition of flashover, the authors have examined the propagation of the discharge on surface under DC voltage in a new laboratory model which has a continuous and radial current distribution. This model is a vat having a circular sector form of variable angles, radiuses and depths filled by an electrolyte. The obtained results on this model show that for a given resistivity of electrolyte: if the current distribution in the horizontal plane is uniform according to the sector angle, the applied critical voltage and the critical current per unit of angle (1deg) are constant for all sectors of various angles, if the current distribution in the vertical plane is uniform according to the depth, the critical flashover voltage and the critical current per unit of the electrolyte depth (1 mm) are constant for all the depths. These results lead to the critical conditions of flashover to be determined by the current per unit of angle and per unit of electrolyte depth (A/deg/mm)