Active power control from large offshore wind farms

Wind power represents a growing share of electricity supply on many power systems around the world. The UK has plans for over 33GW of offshore wind power to be developed before 2020, which would substantially alter the generation mix. The GB electric grid has traditionally depended on fossil fuel fired synchronous plant to control power output and maintain the balance between supply and demand through system frequency regulation. Modern wind turbines are equipped with advanced power electronic converters which provide flexible, controllable, interfaces to the power system, but are inherently driven by an intermittent resource. This paper addresses the control of large offshore wind farms, in order to contribute to the frequency stability of the GB electric grid. It shows that wind farms can be controlled to provide frequency response, within the limitations of the available wind power. The paper then addresses the possibility of using Vanadium Redox Flow Batteries to provide reserve capacity for the wind farm. The paper highlights the many benefits of these batteries in conjunction with wind farms and demonstrates that they can contribute to providing reliable frequency regulation from offshore wind farms.