Grid Frequency Control Design for Offshore Wind Farms with Naturally Commutated HVDC Link Connection

Abstract

This paper considers the formal design for the offshore grid frequency control in an LCC HVDC connected wind farm. The control paradigm is based on using the grid frequency control to regulate the HVDC rectifier angle and hence control the power flow in the system. The dynamics of the system are derived and a grid frequency controller is designed. The mathematical analysis and the control design are verified through PSCAD simulation. Good modeling agreement is obtained for both open and closed loop systems and the work provides a good basis for wider research investigation into wind farm operation including fault behaviour.