Study on the Reaction of Oxygen and Nitrogen under the Effect of Intense Pulsed Arc in Gap Switch

As the current in the gap of the switch increases, the gaseous products produced by the transferred arc may reduce the life of the switches. In the arcing stage, as the arc channel develops, different gas components will interact with each other. In this paper, combined the temperature and volume characteristics of high-current arc, the products of the chemical reaction are analyzed. The calculated arc radius is related to the peak and rising slope of the pulse current. As the radius of the arc increases, the volume of the arc channel expands, and more insulating gas is heated. Furthermore, two characteristic parameters of the arc are investigated respectively. The peak current ranges from 150 kA to 300 kA and the width of the pulse is between 1 ms to 3 ms. The content of nitrogen oxides is measured by a flue gas analyzer in the 4 L sealed cavity with 2.3 atm dry artificial proportional gas. It is observed that the concentration of NO2 remains stable around 570 ppm and the concentration of NO increases progressively with the increase of the peak current. According to the nitrogen-oxygen reaction condition and arc expansion theory, under the experimental parameters, the amount of nitrogen oxides increases with the augment of the calculated arc radius.