High Effective Calculation and 3-D Modeling of Ion Flow Field Considering the Crossing of HVDC Transmission Lines

The 3-D calculation method of the ion flow field is required for the crossing issue of high-voltage direct-current (HVDC) transmission lines. Appropriate computational regions and boundary conditions are critical to the calculation. In this article, a novel method combining charge simulation method-flux tracing method (CSM-FTM) and finite-element method (FEM) is proposed to optimize the ion flow field calculation. The advantage of CSM-FTM in dealing with the opening domain is fully utilized. Quadratic charges are applied in CSM to ensure the calculation accuracy of the space-charge-free electric field. In addition, a hemisphere calculation region is adopted in order to model the HVDC lines with an arbitrary cross angle. The Dirichlet boundary condition on the spherical surface in the FEM calculation is obtained based on FTM. Finally, the electric field of ±800 and ±500 kV lines at a cross angle of 60° is analyzed as an example. By utilizing the proposed method, the calculation area is substantially reduced and the calculation accuracy is significantly improved.