Analysis of Doubly Fed Induction Generators Participating in Continuous Frequency Regulation with Different Wind Speeds Considering Regulation Power Constraints

Abstract

Wind turbines (WTs) participate in frequency regulation, which is one of the means to solve the problem of inadequate regulation capacity in power systems with a high proportion of renewable energy. The doubly fed induction generator (DFIG) can reserve part of power to achieve bidirectional regulation capability through rotor over-speed and increasing pitch angle. In this paper, it is pointed out that the available bidirectional regulation power of the WT is constrained by the maximum regulation power under the rotor speed regulation. The regulation power constraints under the pitch regulation considering the time scale are calculated. The adjustment coefficient of WT participating in frequency regulation is designed. Considering the regulation power constraints, the frequency difference interval in which the WT can provide the regulation power according to the adjustment coefficient is analyzed. The rotor speed and pitch coordinated control strategy of DFIG with different wind speeds is designed. Based on 24-hour measured data from a wind farm, the power constraints and their effects of WTs in the wind farm participating in frequency regulation are verified by simulation. The regulation power of the wind farm, frequency quality, and wind power utilization under the different control strategies are analyzed. The results show that the effects of bidirectional power constraints must be taken into account when evaluating the effectiveness of WTs in continuous frequency regulation.

Enhancing Frequency Regulation Support through Several Synthetic Inertial Approaches for WDPS

“…Based on these topologies, wind turbines are divided into four types depending on the type of electrical generator (induction and synchronous) used and its configuration within the EPS [16][17][18]. However, wind turbines based on doublyfed induction generators (DFIG) are the ones that lead the selection and implementation preferences because they have attained most of the market share in the last decade in most EPS [19][20][21][22][23][24]. Such wind turbines have the capabilities to perform their function within a wide range of angular velocities in response to fluctuating wind.…”