A Calculation Method for the Hybrid Electric Field Under UHVAC and UHVDC Transmission Lines in the Same Corridor

Parallel adjacent erection of UHVAC and UHVDC transmission lines in the same corridor will occur in the east of China. So the calculation method for the ac and dc hybrid electric field over the ground surface under this type of lines need to be studied so as to satisfy the requirements of engineering design and environmental protection. Based on the analysis of mutual influences between UHVAC and UHVDC transmission lines in the same corridor, a calculation method is proposed. The corresponding calculation results obtained with this method are shown as follows. Near the center of UHVAC and UHVDC transmission lines in the same corridor, especially in the side of UHVDC transmission lines, the change of voltages applied to ac conductor bundles can evidently affect the magnitude of the hybrid electric field; the hybrid electric field is sometimes enhanced and sometimes diminished, and the total effect appears subdued in an ac cycle. Except for the area close to the center of this type of lines, that whether the mutual influences between UHVAC and UHVDC transmission lines are considered or not can hardly affect the lateral distribution of the hybrid electric field.