Accurate Numerical Method for Computing Induced Voltage of GIL

Gas-insulated transmission line (GIL) is nowadays becoming popular in high voltage engineering for power delivery. At power frequency, the metal shell enclosing the transmission line will induce eddy-currents. In practice, it is very important to compute the distribution of the associated induced voltage. Due to complicated structure of practical settings, analytical method is limited in use and the voltage distribution for the conductors are not available if using equivalent circuit method. In this paper, the three dimensional (3D) finite element method (FEM) is implemented for solving the eddy-current field. Magnetic vector potential (MVP)-based formulation is used together with the electric scalar potential (ESP), which is easy to use for handling voltage excitations for grounded conductors. An analytical example and a practical engineering problem is solved using the proposed method, good accuracy is observed.