A method for stabilizing a frequency in an AC voltage grid includes exchanging active power between the AC voltage grid and an energy storage device of a compensation installation in which the energy storage device is connected to the AC voltage grid. An electrical power is transmitted in an interconnector that connects the AC voltage grid to a further AC voltage grid. The electrical power is measured. The exchange of the active power is initiated by a control device of the compensation installation depending on a direction of the transmitted power. An installation for stabilizing an AC voltage grid can be used, in particular, to carry out the method.