Measurement and calculation of thermal characteristics of AC surface discharge on a long-time scale

Surface discharge belongs to the non-thermal plasma and there is not a unified temperature available to measure. On the other hand, the path of surface discharge is randomly dispersed and the heat is not easy to accumulate. Moreover, some of the present studies focus on the fast thermal process, and did not pay more attention to the thermal characteristic on a long time scale which is more important in the field of insulation. In this paper, the spatially confined surface discharge produced in a glass tube is presented and the equivalent temperature of air in a glass tube on a long time scale (multiple AC voltage cycles) is assumed. By measuring the surface temperature of the tube wall, the equivalent temperature of air can be indirectly measured. The one-dimensional heat diffusion equation about the air in tube was resolved, in which the magnitudes of the equivalent thermal conductivity of air and the heat sources on a long time scale were estimated. Compared with the measured data, the calculated results of the equivalent temperature of air have a very similar way of variation with the surface temperature of the tube wall. Above mentioned results show that it is feasible to measure the thermal characteristics of surface discharge by this method.