Ion flow field distribution near the crossing of two circuit UHVDC transmission lines

Abstract

The 3D upstream FEM is applied to calculate the ion flow field near the crossing of two circuit ±800 kV UHVDC transmission lines. In order to deal with the interaction of two circuit lines, an improved space charge density correcting treatment on the conductor surfaces is proposed. Compared with the traditional method, the conductor surface electric fields could be closer to the corona onset electric fields by using the improved correction treatment. Then, an experimental platform is established in the laboratory to testify the calculation method. Comparison of the calculated and measured ground-level ion current density proves the validity of calculation method. Finally, the distribution characteristics of space charge density and electric field strength near the crossing area are analyzed. The crossing structure of bipolar HVDC lines improves the corona discharge level in the opposite polarity crossing area significantly.