The finite element model of electric-thermal dynamic coupling about HVDC grounding

The aim of this paper is to calculate the current flowing process of HVDC grounding in single stage-earth operation mode. This paper uses finite element model (FEM) to solve the problem. We derived the finite element equation with taking into account temperature effect of soil parameters by setting the electrical and thermal parameters of soil element as the functions of temperature and taking the ground conductor as a one-dimensional line unit to reduce the amount of computation. Besides, the spatial transformation method is adopted to realize the transformation of the infinite space and the finite space and to solve the problem that the traditional finite element method can only calculate the bounded field. Finally, the numerical results of the model are compared with the measured results and the calculated results of the international accepted Grounding Calculation Software CDEGS, respectively. The validity of the model is verified.