Shielding Effect of HVAC Transmission Lines on the Ion-Flow Field of HVDC Transmission Lines.

The HVDC and HVAC transmission lines running on the same tower is a promising technology to improve the transmission capacity of an existing corridor. The ions generated by corona discharge of HVDC transmission lines will strengthen the ground-level electric field, which may endanger human exposure. To investigate how the presence of HVAC transmission lines changes the ion-flow field, experiments are carried out on an indoor test model with bipolar dc and three-phase ac lines. The experiment results are then compared with the simulation results. The experiment and simulation results show that the HVAC transmission lines have a shielding effect on the ion-flow field from the HVDC transmission lines running above. Finally, the ground-level electric field and ion current density of the \pm 800–kV HVDC and 500-kV HVAC transmission lines running on the same tower are calculated. [ABSTRACT FROM PUBLISHER]