A DC voltage grid includes an electrical conductor electrically interconnecting electrical components, with a DC voltage applied between parts of the electrical conductor. An actuator is configured to vary the DC voltage such that a value of the DC voltage depends on at least one state of the DC voltage grid. Information about the at least one state is transmitted to the electrical components of the DC voltage grid by way of the DC voltage. A wind farm having wind turbines connected to such a DC voltage grid and a method for operating such a DC voltage grid or such a wind farm are also disclosed. The DC voltage of the DC voltage grid is controlled or regulated depending on a state of the DC voltage grid.