Accurate and Efficient Calculation Method for Ion Flow Field Near Direct Current Voltage Divider

Abstract

The surface of grading rings in DC voltage divider may cause surface wear or scratch, resulting in corona phenomenon. Due to the influence of space charges and surface charges, the total electric field near DC voltage divider is different from the nominal electric field. For the problem of solving the ion-flow field near the DC voltage divider, this paper proposes an improved method based on upwind Finite Element Method (FEM). According to the nominal electric field results, the updated switch state of the charge density is determined, and then the upwind FEM is used to update the node charge density. This method uses a dual-scene iterative method to converge for the multiple grading rings, which improves the convergence. The correctness of the method is verified by the coaxial cylindrical electrode. Finally, the ion-flow field near 500 kV DC voltage divider is calculated. The results show that the total electric field near the grading ring becomes more uniform due to the effect of space charges and surface charges. In the space far from or close to the grading rings, the total electric field will increase or decrease compared with the nominal electric field. The method in this paper provides guidance for the calculation of the ion-flow field near the DC divider and its insulation design.