Coordinated design of active and reactive power modulation auxiliary loops of wind turbine generators for oscillation damping in power systems

The ability of modern wind turbine generators (WTGs) to rapidly and independently control active and reactive power outputs makes them attractive for the purpose of oscillation damping in power systems through P and Q modulation auxiliary loops. However, the problem of coordination and interaction of P and Q control loops emerges. The paper proposes a methodology for coordinated design of active and reactive power modulation loops of wind turbine generators. The method is based on a nonlinear constrained optimization approach with a properly chosen modal performance index as an objective function. The coordinated design is validated on the two-area benchmark system with a wind farm (WF) of significant capacity. The advantage of the control loops coordination approach is demonstrated through separate and simultaneous tuning of both controllers. Results show substantial improvement in damping low frequency inter-area mode, as well as proper coordination achieved between P an Q loops through the proposed methodology.