In this paper,a 3D upstream finite element method is developed to analyze the ionized electric field around the UHVDC transmission lines including the building near it.The ionized electric field around the building is reduced due to the shielding effect of the building and the shielding distance is about three times its height.The ionized electric field including the human body model on the building and away from the building is also taken into account.The ionized electric field distortion ratio of the human body model is discussed in this paper.The distortion ratios for the positions on the building are less than those on the ground.
The cavity-mode resonance effect could result in significant degradation of the shielding effectiveness (SE) of a shielding enclosure around its resonance frequencies. In this paper, the influence of coated wall loss on the suppression of the resonance effect is investigated. For this purpose, an equivalent circuit model is employed to analyze the SE of an apertured rectangular cavity coated with an inside layer of resistive material. The model is developed by extending Robinson's equivalent circuit model through incorporating the effect of the wall loss into both the propagation constant and the characteristic impedance of the waveguide. Calculation results show that the wall loss could lead to great improvement on the SE for frequencies near the resonance but almost no effect on the SE for frequencies far away from the resonance.
