Coordinated Nonlinear Control of STATCOM - BESS and Excitation for Transient Stabilization and Voltage Regulation

Nowadays, the generation profile of electric energy systems changes with the increasing integration of renewable energy sources. Wind turbines with Doubly-Fed Induction Generators (DFIG) are replacing bulk synchronous generators. The replacement of these synchronous generators will affect power system dynamics in a large extent. Standard controllers for synchronous generators like governors and exciters traditionally provided power grids with robustness during major disturbances. Without synchronous generators this control capability is not available anymore. On the other hand technologies such as energy storage and FACTS are used for various power network applications. Recently, a lot of research is focused on the development of advanced controllers for these technologies that will enhance the capability of modern power systems to withstand large disturbances. Motivated by the fact that advanced controllers will play a key role in the transformation of today’s power grids into sustainable, reliable and robust future grids, we propose a nonlinear coordinated controller for a STATCOM integrated with a Battery Energy Storage System (BESS) and a generator excitation controller. The proposed coordinated controller guarantees transient stability and voltage regulation of a synchronous generator. The controller is derived based on Multi-Input Multi-Output feedback linearization theory. Our proposed controller is applied on the modified IEEE 14 bus system and its performance compared to a benchmark controller during major contingencies is illustrated through simulation results.