Enhancing the grid compliance of wind farms by means of Hybrid SVC

Despite reactive power control capability of the modern wind turbine generator units have almost reached the capability of the traditional generator units the applied wind farm configuration can result insufficient reactive power capability in the point of common coupling. For instance, when utilizing AC grid connection, long electrical distance from the main grid or possible high charging current of the offshore sea cable usually require additional compensation capacity in the cable ends to ensure proper voltage profile of the farm and meet the Grid Code requirements set by the utility. In this paper dynamic compensation scheme, called Hybrid SVC, is presented to improve the reactive power control capability and thereby feasible grid connection of wind farms with AC grid connection. In addition, fast controllability of the Hybrid SVC unit may also improve the response of the wind farm in case of low voltage conditions. After discussing the benefits of dynamic compensation in connection of wind farm application in general, possible benefits of Hybrid SVC based dynamic compensation in case of medium size offshore wind farm is demonstrated in PSS/E and RTDS environments. It is concluded, that a Hybrid SVC device with proper ratings could improve the feasible grid connection of wind farm and enable decreased ratings for the wind turbine generator units.