Electromechanical interactions of full scale converter wind turbine with power oscillation damping and inertia control

Abstract

In this paper, the impacts of power oscillation damping (POD) and inertia controller on the structural system of wind turbine (WT) are evaluated. Synchronous generators (SGs) fitted with well-established power system stabilisers (PSS) are declining leading to reduced power system inertia and damping capability which are critical to system stability performance. The WTs will become more dominant and should therefore be capable of providing inertia response and POD to maintain system performance. However, there has been some concern amongst the industry regarding effects of inertia and POD controls on WT performance when the active power modulation is utilised by both controllers particularly during frequency event that leads to low-frequency power oscillations. A detailed grid-connected full-scale converter (FSC)-WT system which combines aerodynamic, electrical, and mechanical characteristics was developed to assess its interactions with the POD and inertia controllers and also the resulting impact on the WT structural system. The obtained results show that the implementation of the POD/inertia controllers on the FSC-WT can improve the inertia response and oscillation damping but will affect the dynamics of its drivetrain, blades, and tower. However, these effects are shown to be smaller than the effects caused by the credible electricity system faults.