Modelling and calculation of negative DC corona plasma in coaxial cylindrical electrode

Corona is one of the critical technical problems in ultra-high voltage direct current (UHVDC) transmission. Most of corona models using Kaptzov assumption as boundary condition did not consider the secondary electron emission mechanism. Moreover, the effects of electron diffusion, charge recombination and photoionization were not taken a full consideration when corona current was larger. In this paper, a comprehensive model based on the simplified plasma fluid model has been proposed, which furtherly considers electron diffusion, charge recombination and photoionization. Meanwhile, the negative DC corona plasma in coaxial cylindrical electrode has been calculated. Finally, the impacts of different factors on the calculation results have been analyzed and the distributions of negative DC corona plasma and corona field have been observed.