Decentralized Reactive Power Control of Wind Power Plants

Wind power is a rising renewable resource in the energy portfolio worldwide. A huge research effort has been applied for the efficiency of the wind turbines, i.e. for the real power injections maximization; on the other hand, reactive resources exploitation still need a deep investigation. This paper presents the results of a research project jointly carried out by SIEMENS and the Politecnico di Milano. One of the issues studied is the grid integration of the reactive power capabilities of many wind power plants connected to the 150 kV subtrasmission grid. Currently, such resources are not integrated in the on-line management of the Transmission System Operator (TSO) control center; consequently, a local approach has been developed, i.e., a generation control mainly based on local measurements, exploited by the local substation regulation and control apparatuses. Nevertheless, wind farms typically have a plant control center: a detailed modeling of the control schemes has been implemented to evaluate the interaction between the substation regulators and the wind power plants. Tests have been carried out on a realistic representation of a portion of the Italian subtrasmission system.