Electrical gas breakdown analysis at non-uniform geometries

Sulphur-hexafluoride (SF6) has found a wide range of applications in the electric power industry due to its superior insulating and arc quaching properties. Corona discharges in SF6 are of engineering importance and in this thesis a rod-plane electrod system with various radius of curvatures and gap distances is considered in order to calculate for the positive corona onset voltages. The simulation model for the calculation of the positive corona onset voltages depends on the sizes of the primary and the successor avalaches produced. The discharge become self-sustained when the size of the successor avalanches reaches to that of the primary one. The calculated results obtained in this study are compared with those of the available experimental ones in the literature. It is observed that the predicted positive corona onset values agree very well with the respective experimental results.