Current-voltage characteristics of corona in rod-plane gaps as influenced by temperature

A method is described for calculating the onset of positive corona in rod-plane gaps in air as influenced by temperature. The method is based on the criterion of self-sustained luminous filamentary streamers in the gap. The onset voltage is a prerequisite for calculating the current-voltage characteristics using an iterative method that correlates the corona space charge density to the avalanche growth inside the ionisation-zone around the rod. The onset and spark breakdown voltage decrease with the increase of temperature, in conformity with previous experimental findings. Not only the calculated onset voltage but also the current-voltage characteristics agree reasonably with those measured experimentally at room and high temperatures.