Dynamic Active Power Control in Type-3 Wind Turbines for Transient Stability Enhancement

This paper concerns the integration of renewable generation in transmission corridors that are at their transient stability limits. Renewable resources can provide faster active power control compared to steam or hydraulic turbines. Here, grid-integrated Type-3 wind turbine generators (WTGs) are considered. In particular, an adaptive dynamic power reduction (aDPR) scheme is proposed for WTGs to improve the transient stability margin of synchronous generators (SGs), such that an already congested line can host additional renewable energy. The proposed control consists of three parts: a dynamic power reduction (DPR) scheme such that the WTG can act as a braking resistor, an adaptive ramping control back to the original WTG power output, and a supplementary reactive power damping control. The control is activated only when a severe contingency is detected, and can be implemented on existing WTG controllers. The design accounts for the wind hub rotor dynamics, in order to optimize the blade pitch angle and rotor speed response. Its effectiveness in disturbance events is demonstrated on a single-machine infinite-bus system.