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This paper presents a hybrid meshing scheme for improving the solution accuracy for modeling 3-D ferromagnetic plates. Combining with the assumption of double exponential distribution across plate thickness, another analytical expression of the 2-D bilinear basis functions is proposed for the distribution of electromagnetic components on the planar of the plate. Then, the mesh refinement is assigned to the edge region of the plate. The numerical testing validates this hybrid meshing technique, and proves that it can reduce the number of unknowns and improve the accuracy of solution. [ABSTRACT FROM AUTHOR]

When the nacelle of a wind turbine is struck by lightning, lightning electromagnetic pulse (LEMP) is generated inside the nacelle and consequently impacts inside electronic devices or even seriously destroys them. In order to study the LEMP inside the nacelle, this paper firstly built a full-scale model of a non-metallic nacelle. The lightning electromagnetic environment in the nacelle was simulated and analyzed by the transmission-line matrix method. Then the protective measures of applying metallic shielding mesh on the nacelle were studied, including the mesh size and material of the shielding mesh on the protective effect. The results show that LEMP in the nacelle can be effectively attenuated by metallic shielding meshes. The shielding effect is highly dependent on the conductivity of the shielding mesh material and the mesh size. [ABSTRACT FROM AUTHOR]

Abstract: This paper evaluated lightning-induced magnetic fields in a building with large metallic plates using an equivalent circuit method. In the evaluation the metallic structure of a building during a lightning stroke was represented by an equivalent electrical network. Electrical network equations were built to find the current distribution in the structural elements, and subsequently the lightning-induced magnetic fields around the building. Special techniques were presented in the paper to model the large metallic plates and to derive equivalent circuit equations and circuit parameters. The coupling of metallic plates to building structural elements was also addressed. The proposed method was validated experimentally on a scaled structure model in the laboratory. Finally, lightning-induced magnetic fields in a laboratory building were characterized. It was found that the metallic plates changed the current distribution significantly within the metallic structure, and subsequently the lightning-induced magnetic fields in the building. [Copyright &y& Elsevier]