The Determination of the Calculation Area of Ion Flow Field under HVDC Transmission Lines with Different Crossing Angles

In this paper, the charge simulation method (CSM) and the 3D upstream finite element method (FEM) are used to calculate the ion flow field in the crossing region of HVDC transmission lines. First, in order to model the high-voltage direct current (HVDC) overhead lines with arbitrary crossing angles, the cylindrical calculation area is adopted. Then, combined with the position of the intersection point, a method for determining the artificial boundary with any crossing angle is proposed. Under the premise of ensuring the calculation accuracy, the modeling region is given to reduce the amount of 3D calculation. Finally, the method is used to analyze the ground-level electric field in the crossing area of $\pm 500kV$ lines, and the influence of the crossing angle on the ion flow field is studied. In addition, the relationship between the position of the peak of ground-level electric field and the crossing point is given, which provides a theoretical reference for the crossing of HVDC transmission lines in engineering practice.