Primary frequency regulation strategy for doubly-fed induction generators based on virtual inertia

Abstract

With the continuous increase of wind power generation capacity, the necessity of wind power generation participating in primary frequency regulation is also increasing. Most traditional doubly-fed induction generators do not have the capability of frequency regulation control. To solve this problem, the primary frequency regulation strategy for doubly-fed induction generators is designed based by using the inertia of wind turbines. The power control principle and frequency response process of doubly-fed induction generators are studied. On this basis, a strategy of primary frequency regulation based on virtual inertia is proposed. The method enhances the ability of the doubly-fed induction generator to adjust transient and steady-state power when the frequency of the power network changes, and realizes the doubly-fed generators to take part in the primary frequency regulation of the power system. The 3-generator 9-bus model is built using MATLAB/Simulink, in which wind power capacity accounted for 20%. Using this model, it is verified that the virtual inertia strategy can make the output power of doubly-fed generator change with the frequency of the power grid, can effectively participate in the primary frequency regulation of the power grid.

Keywords

• frequency regulation
• doubly-fed induction generator
• virtual inertia