A calculation method for 3-D ionized field under HVDC transmission lines

Considering the influence of wires sag, towers, up-and-downs on the ground, surrounding buildings and other situations, the ionized field under HVDC transmission lines is actually a 3-D field and its calculation method is necessary to be found. In this paper, a method to calculate the 3-D ionized field was proposed to be based on the Deutsch assumption. After the validity of the method is testified, some conclusions will be given.