An overvoltage protective device for wind energy installations is designed for connection to a connecting line having at least one inductance between a wind energy installation and a grid system. The overvoltage protective device has a controller which operates a limiting unit as a function of an overvoltage at the wind energy installation. The limiting unit comprises a spur line having an induction module and a power tapping module which is provided with a switching unit. This yields a second power strand which can accept a considerable reactive current if necessary, thus increasing the voltage drop across the inductance, as a result of which the voltage acting on the wind energy installation is reduced.