Simulation of Ion-Flow Field Using Fully Coupled Upwind Finite-Element Method

An improved method to simulate the ion-flow field generated from the corona discharge on HVDC transmission lines is proposed. To remove the oscillations in simulation of charge conservation law, an upwind weighting function is adopted in the finite-element method. The Poisson's equation and the charge conservation law are solved simultaneously through Newton's method of iterations, which accelerates the convergence of the algorithm. A rule for charge density on boundary in the bipolar problem is proposed in this paper, which ensures the stability of the iterations. The computation time, convergence rate, and accuracy of the proposed method are analyzed. The proposed method is verified by analytical and experimental results, and then it is applied to the prediction of the ion-flow field from a $\pm$ 1100-kV HVDC transmission line.