Numerical Investigation on the Effects of Wind and Shielding Conductor on the Ion Flow Fields of HVDC Transmission Lines

Ion flow field is an important aspect of high voltage direct current (HVDC) transmission lines. In this paper, we apply the upwind finite volume method for solving the ion flow field of three HVDC configurations to clarify the effect of the wind and the role of shielding conductors. For the monopolar configuration installation, the ground current distribution with underbuilt shield wires was studied numerically and experimentally. For the ±250 kV bipolar configuration, the calculated peak electric field and current density are verified with the values in a reference. The ±500 kV bipolar configuration is used to investigate the change in electric field and ion current within the same corridors of the existing HVAC lines. We analyze the ion flow field with and without the dedicated metallic return conductor (DMRC). In the absence of wind, the maximum of the electric field is lower than that of the HVAC lines and the current density is very low on the ground. In the presence of wind, the electric field and the current distribution become unsymmetrical on the ground level. The peak current density increases significantly on the downwind side. The HVDC line without DMRC has the electric field peak higher than that of the HVAC lines. With the higher wind shear coefficient, the peak of the electric field and the current density increases on the downwind side. Overall investigations summarize that DMRC can effectively reduce the peak of the electric field to be lower than that of the existing 500 kV HVAC lines under all wind conditions.