A literature review has been conducted on the topic of wind farm supervisory controls. The context is the development of a supervisory control system for the NOWITECH Reference Windfarm (NRW), which consists of 120 DTU 10 MW wind turbines. The NRW is representative of the next generation of large offshore wind farms which, from the perspective of the operator of the onshore electric grid, is expected to behave like a conventional powerplant. It was found that existing analysis methods and control strategies are insufficient for the NRW. It is recommended to develop engineering analysis methods for the atmospheric boundary layer over a large wind farm; to create a unified state-space model of the NRW, which includes aerodynamics, structural dynamics, control systems, and electrical load flow; to verify existing techniques for wind field state estimation using standard turbine sensors; and to evaluate the practice of using very simplified load metrics, like rotor hub loads, to represent the costs of fatigue degradation in the wind turbine structures. It is further recommended to use these analysis tools to develop an "offline" optimal control strategy, where the control laws, and the optimal tuning of selected parameters, are determined upfront.