Real-Time Simulation of Grid-Connected Wind Farms Using Physical Aggregation

The electromagnetic transient (EMT) simulation of a power system interconnected with wind farms involves such intensive computations that fully digital real-time simulators are among the effective tools for performing such simulations. To practically exploit real-time simulators for the simulation of wind farms with numerous wind turbines, the application of aggregation techniques is inevitable. In this paper, a detailed EMT model of a grid-connected wind farm with ten doubly-fed-induction-generator-based General Electric 1.5-MW wind turbines has been implemented on an advanced PC-Cluster-based real-time simulator. Three levels of physical aggregation methods are presented to reduce the computational efforts of the real-time simulation while maintaining adequate accuracy. A combination of these aggregation methods with parallel processing allowed the real-time simulation to be carried out with a fixed time step of 50 μs and high accuracy. Various fault transient results are provided for all the aggregation levels and compared against results from the detailed wind farm model. The validity of the proposed methods and real-time simulation results has also been confirmed by comparing with offline simulation results in MATLAB/SIMULINK.