Physical rotor inertia of DFIG wind turbines for short-term frequency regulation in low-inertia grids

Abstract

This paper investigates DFIG wind turbine rotor inertia and proposes reliance of its use for short term primary frequency regulation in low-inertia power systems. Such systems are more susceptible to frequency deviation, and there is question as to whether DFIG wind turbines contribute sufficient physical inertia to frequency regulation. A laboratory DFIG wind turbine emulator is used to evaluate stator frequency regulation immediately following electrical load change. Linearization is used to estimate torque, speed, and frequency deviation moments after transient onset. Evidence shows that the DFIG assembly does provide sufficient physical inertia for short-term primary regulation by inertia alone, and that large transients pose a challenge to accommodate by coordinated protection or control.