Lightning impulse breakdown voltage of nitrogen and air under rod-plane gap

This paper presents the study on lightning impulse breakdown voltage of nitrogen and air by the variation of gap distance, pressure and humidity in rod-plane gap. The range of gap distance is 5-35 mm; pressure 2-5 bars; relative humidity 35%, 60% and 82%, both positive and negative polarities. According to the results, the breakdown voltage of both gases is increased with gap distance, pressure and humidity. The breakdown voltage of negative impulse is higher than the positive one. The ratio between the negative impulses to the positive one is increased according to gap distance. Furthermore, we compare the characteristics of both gases, it is found that the breakdown voltage of air is similar to nitrogen as well.