Comparative studies on frequency responses of type 3 wind turbines and synchronous generators

This paper describes the properties of inertial response (IR) and primary frequency response (PFR) of Type 3 wind turbines (WTs) for exploring a combined frequency regulation approach, which allows the dynamic frequency response of Type 3 WTs in coordination with that of synchronous generators (SGs). First, this paper investigates the inertia control (IC) and primary frequency control (PFC) strategies for Type 3 WTs from the perspective of the basic foundations and implementations. Then in terms of response time and transient energy source, the comparisons of IR and PFR between Type 3 WTs and SGs are made. On this basis, an approach is developed in order to reduce the mismatch in the time constants of SGs' governor response and Type 3 WTs' PFR through introducing an artificial filter-based delay in the overspeed or hybrid PFC. The proposed approach provides a guidance for taking full advantage of the frequency regulation capability in wind power penetrated power systems. Finally, simulation results demonstrate that the proposed approach effectively renders a limit on the extra power released from Type 3 WTs and meanwhile guards an allowable rotor speed droop throughout a transient frequency event.