Contribution of DFIG wind turbines to Primary Frequency Control

Abstract

In recent years, worldwide power systems are experiencing a steadily growth in wind power penetration. A common concern in the operation of such systems is related to the frequency stability. Modern variable speed wind turbines have a limited capacity in providing ancillary services, such as: fastfrequency response and primary frequency regulation. This thesis aims at developing a new methodology for the analysis of frequency dynamics in largescale power systems with high level of wind energy share. Firstly, a simplified electromechanical model of a doubly fed induction generator (DFIG) based wind turbine has been proposed. In addition, a virtual inertia controller version of the optimized power point tracking method (OPPT) has been adapted for this kind of wind turbines. In this method, the maximum power point tracking curve (MPPT) is shifted to drive variations in the active power injection as a function of the grid frequency deviation, by exploiting the available inertial resources. The proposed methodology integrates the model in a primary frequency control scheme to assess the interaction with the rest of the plants in the power system.