A method is provided for determining a voltage bounding range defining a range of a wind turbine reference voltage for a wind turbine for controlling an output voltage of the wind turbine at a wind turbine output terminal. The method includes obtaining information regarding an electrical characteristic of a transmission line connecting the wind turbine output terminal to a point of common coupling to which plural other wind turbines are connectable. The method further includes defining the voltage bounding range based on the electrical characteristic of the transmission line.