Influence of Wind on the Electric Field and Ion Current Environment of HVDC Transmission Lines

Transverse wind has a large influence on the electric field and ion current environment of HVDC transmission lines. The flux tracing method (FTM) is modified by including wind velocity in the defining equations of corona-generated monopolar dc space-charge modified fields. The modified method, called FTM-Wind, is derived by making appropriate assumptions and identifying wind-modified pattern of flux lines. Computations are made using FTM-Wind for hypothetical monopolar and bipolar dc transmission-line configurations to obtain a physical understanding of the influence of wind in changing the pattern of flux lines and, as a consequence, changing the ion current distributions on the ground plane. The FTM-Wind is also applied to study the influence of wind on the ion current profiles of a 900-kV bipolar dc test line for which long-term measurement data are available. Calculations show reasonable agreement with measured ion current profiles grouped according to ranges of wind velocity.