Analysis of a multi turbine offshore wind farm connected to a single large power converter operated with variable frequency

This paper deals with the analysis of power, generated by offshore wind farms, connected to a single large power converter (SLPC), operating at variable frequency (VF) or at constant frequency (CF). The results are compared with a scheme widely used in current onshore wind farms, consisting of multiple power converters (MPC), one for each wind turbine. A methodology to analyze different wind speed scenarios and an optimum electrical frequency search procedure is presented and applied to a case study. The advantage resulting from a wind farm containing only one power converter, with the associated cost, losses and maintenance reduction and reliability increase, is analyzed, taking into account both wind speed variability in wind farms and the number of wind turbines. The SLPC-VF scheme is also compared to a constant frequency scheme SLPC-CF, and it is shown that a significant power increase of more than 11% can be obtained with SLPC-VF. Finally, a multiple regression analysis is applied in order to get a mathematical expression which models this behavior.