Aggregating wind farm with DFIG in power system online analysis

Increasing numbers of wind turbine units are connected to electrical power systems, the full model of wind farms with high number of wind turbines is a high order model which isn´t appropriate for online system security analysis and stability margin computation. This paper presents a new way of aggregation of doubly fed induction generators(DFIGs) wind turbine units which have a four-quadrant ac-to-ac converter with vector control applied connected to the rotor windings, increasing the transient stability margin of the electrical grids and is different from capacity under different incoming winds by one single wind turbine unit to perserve the chief performance of aggregated wind turbine units for optimizing online computation time. The aggregation includes aggregating wind turbines, DFIGs and its control system, and collector system and gives real time parameters of DFIGs under operating condition according to the identified parameters. The equivalent model has the same structure as the original system considering development an equivalent representation of wind farm collector system for power system planning studies. The validity of the proposed full system and reduction generation system was proved by the comparison study.