A system transmits electrical power between a first and a second alternating voltage network. A self-commutated converter can be connected to the second alternating voltage network, the converter being connected to an unregulated rectifier via a direct voltage connection. The unregulated rectifier can be connected to the first alternating voltage network on an alternating voltage side. The system has a network generation device, which can be connected to the first alternating voltage network and is provided for generating an alternating voltage in the first alternating voltage network. The network generation device is configured to exchange reactive power and active power with the first alternating voltage network. Furthermore, a method is provided which stabilizes a network frequency of the first alternating voltage network, in which the network frequency in the first alternating voltage network is regulated by changing a voltage at the direct voltage terminal of the self-commutated converter.