Lightning induced currents along vertical cables inside wind turbine towers

The purpose of this paper is to propose a numerical model based on antenna theory for evaluating the induced current distribution along vertical electric cables in wind turbine towers struck by lightning. The vertical cable installed within a wind turbine tower is modeled as an antenna above a perfectly conducting ground. The electric field inside the tower produced when lightning current flows through the tower body is treated as an incident field to the antenna. An electric field integral equation (EFIE) with appropriate boundary conditions is derived to relate the currents induced in the cable and electric fields. The EFIE is solved numerically to obtain the induced currents in vertical cables. This current distribution based on the antenna theory is compared with that predicted by the transmission line model and a good agreement is shown between them, which confirming the validity of the proposed method.