SYSTEM AND METHOD FOR CONTROLLING THE TRANSMISSION GRID FREQUENCY AND/OR VOLTAGE FROM THE DISTRIBUTION NETWORK

The invention relates to a system and to a method for controlling the voltage stability and/or the frequency stability in an energy supply system (1), that has a transmission network (2) of a first voltage plane, and at least one distribution network (3) coupled thereto via a transformer device (4) of a second voltage plane that is lower as compared to the first voltage plane, wherein the distribution network (3) is connected to a number of controllable network subscribers (5, 6, 7). The frequency or active power and/or the voltage or reactive power at a node of the transmission network (2), values of electrical network state variables on at least one node of the distribution network (3), and values of electrical subscriber state variables of the network subscribers (5, 6, 7) are detected. Subsequently, a network state is evaluated, wherein the availability of each network subscriber (5, 6, 7) for an additional power input and/or power output is determined. Furthermore, a set point value deviation of the detected variable in the transmission network is determined and is transmitted to a control module, which identifies those of the available network subscribers (5, 6, 7), which are able to carry out a measure for compensating for the set point deviation (Δf, ΔU). Subsequently, a power output preset, in particular a power change specification, is determined for at least one of the network subscribers (5, 6, 7) and put at the disposal of said network subscriber (5, 6, 7) such that the set point value deviation (Δf, ΔU) can be compensated to zero.