Inter-area Oscillation Damping Controller for DFIG based Wind Power Plants

Low-frequency inter-area oscillation is typical for transmission tie-line interconnecting neighboring power systems. Inter-area modes result from generators in one area of the power system oscillating against another group of generators in another area across a weak transmission tie line. Modulating active and reactive power in a wind turbine system equipped with a Doubly Fed Induction Generator (DFIG) may effectively dampen inter-area oscillation. In this paper, modifications of Rotor Side Converter (RSC) control and Grid Side Converter (GSC) control by adding active and reactive Power Oscillation Damping (POD) controllers to improve the dynamic system response are studied. Kundur's well-known two-area system is adopted to demonstrate the impacts of active POD and reactive POD controllers of DFIG on the inter-area oscillation using the PSCAD electromagnetic simulation tool. Besides, system stability is studied based on a frequency sweep using the impedance ratio of the different subsystems inside Kundur's system. The Nyquist Stability Criterion (NSC) is adopted to determine system stability.