Fully Coupled Finite Element Analysis for Ion Flow Field under HVDC Transmission Lines Employing Field Enhancement Factor

A fully coupled finite element analysis (FEA) technique was proposed for solving the ion-flow field due to corona discharge under a high-voltage direct-current (HVDC) bipolar transmission line employing a field enhancement factor. To cover the shape and roughness effects for the stranded wire conductor, the field enhancement factor was introduced in the charge generation mechanism. The employed fully coupled FEA can solve the corona electric field with space charge propagation without the Deutsch assumption and is stable and fully convergent regardless of the possible higher values of wind speed. First, we simulated a dc ±500 kV transmission line tower consisting of six subconductor bundles in a bipolar configuration. Furthermore, the accuracy and the reliability of the simulated results were validated using the experimental results from the literature for a dc ±800 kV one-bipolar transmission line with six subconductor bundles. Moreover, the electric fields were assessed with and without consideration of the space charge, including the wind effect. Overall, the simulated results agree with the experimental results from the literature.