Attaining reactive power capability requirements for offshore wind power systems

The prospected diffusion of offshore wind farms (OWFs), to be connected to high-voltage transmission networks, arises the need of dealing with specific technical requirements posed in grid codes by transmission system operators (TSOs). Among them, the compliance with specific reactive power capabilities at point of common coupling can have significant implications in the design stage, for the definition of the needed size and position of compensation devices. In this context, an optimisation problem is proposed in this paper to determine the size of a reactive power compensation device coping with grid code requirements to connect an OWF to transmission system. The problem involves full AC load flow constraints along with nodal voltage and power rating boundaries. The proposed procedure is applied to an offshore wind farm test system to attain the Italian TSO grid code rules.