Onset voltage of positive glow corona in rod-plane gaps as influenced by temperature

Abstract

The postulate put forward by Hermstein to account for the positive glow corona was widely accepted at first and later criticised. Loeb's alternative postulate has not been fully satisfactory. In this paper, a method is described for calculating the onset voltage of positive glow corona in rod-plane gaps in air at room and high temperatures. The method has a flavour of both the Hermstein and Loeb postulates, but is based on the physics of air discharges occurring in the ionisation zone around the stressed rod. The threshold voltage of onset streamers and their development at higher voltages are prerequisites for calculating the onset voltage of positive glow. The threshold and onset voltages increase with the gap spacing at room temperature and decrease with the increase of air temperature for the same gap geometry in conformity with previous findings. The calculated threshold voltage and repetition rate of onset streamers, in addition to the onset voltage of the positive glow agree reasonably with those measured experimentally.