H Bagherian - Faculty of Electrical & Computer Eng-Shahid Beheshti University G.C-Tehran- IRAN
H Kazemi Karegar - Faculty of Electrical & Computer Eng-Shahid Beheshti University G.C-Tehran- IRAN

Increasing demand for wind power generation forces the installation of wind farms with higher capacities. Higher capacity of wind farms can be attained by using wind turbines with taller structures. So the probability of lightning strikes increases in the new generation of wind farms and more efficient lightning protection systems should be used in order to prevent the great costs of the lightning strike damages to wind turbines. Blades are the most probable parts of the wind turbines to get struck by lightning. One of the most common lightning protection system for wind turbine is using several metallic receptors on the blade surface which are connected to metallic down conductors. These metallic down conductors are connected to the electrical ground. In this paper the transient impedance of a wind turbine blade is obtained by using a software on the basis of Finite Element Method ( FEM ) named COMSOL Multiphysics. A wind turbine blade model with two receptors near the tip is modeled in COMSOL environment which is surrounded by air and a lightning current with Heidler function model is applied to the blade in two different points. One of them is on the blade body on its tip and the other one is on one of the receptors. The voltage and the transient impedance curves at the injection points are obtained by the simulations in both cases and the results are compared in order to investigate the effects of receptors. A blade model of a special wind turbine which is V47 made by VESTAS company is used for this study.

COMSOL, grounding mesh, lightning current, receptor, transient impedance, wind turbine blade