Positive switching impulse discharge characteristics and voltage correction of rod-plane short air-gap at altitude of 4000 m and above

According to the laboratory investigations carried out on the positive switching impulse discharge performance of rod-plane short air-gaps less than 500 mm simulated the atmospheric pressures of the altitude of 4000 m and above in the artificial climate chamber, this paper discusses the effects of the altitude and the atmospheric conditions on the positive switching impulse discharge performance of rod-plane short air-gaps of 200∼450 mm, and puts forward that the discharge voltage of the air-gaps is related to the relative air density and the temperature and the absolute humidity, and that the 50% positive switching impulse discharge voltage of a rod-plane short air-gap is the power function of the product of relative air density and the absolute humidity, and that the characteristic index of the effect of atmosphere on the discharge voltage is about 0.41 for the short air-gaps less than 500 mm. Based on the analysis of the tested results, it puts forward the atmospheric correction factor of discharge voltage of the short air-gaps at the positive switching impulse voltage.