In order to explore a new detection method of partial discharge（PD）for switchgear

gas analysis method

the simulation experiments about the characteristics of air decomposition components under different PD intensities are carried out in this paper. The model of air-gap insulation defect is employed to conduct the decomposition experiments caused by PD with duration of 24 h on the decomposition experimental platform

and the correlation characteristics of the gas composition

concentration

gas production rate with discharge quantity are studied. The experimental results show that the air decomposition components are CO

NO

NO2 and O3under PD caused by the air-gap insulation defect

and the concentration of each component varies from each other. The concentration of CO and NO2 increases with the increase of the average discharge quantity QPduring a power frequency period. The growth trend of "linear-saturation"is presented. And the NO2 appeared to saturate before CO do and its degree of saturation is lower than that of CO. The correlation between the gas production rate of CO and the QPis approximately linear under low PD intensities.