Stability improvement of large-scale power systems in the presence of wind farms by employing HVDC and STATCOM based on a non-linear controller

Abstract

In this paper, a non-linear generalized predictive control (NGPC) has been used for the stability analysis in a hybrid power system consisting of series and parallel compensators in the presence of wind farms. In this system, STATCOM has been used as a parallel compensator for improving reactive power of the wind farm, and HVDC is employed to improve damping of transmission line connected to the power system. The proposed method is based on two internal and external control loops. The internal control loop is used to apply the switching signals suitable for the rotor-side converter in DFIG, HVDC’s converter, and the STATCOM inverter. In the external control loop, a disturbance observer has been employed to estimate the aerodynamic torque and to control the wind turbine’s speed. The aim of designing the observer is to evaluate the robustness of the controller under the changes of internal parameters of the system. The simulations have been implemented in the MATLAB software in different scenarios on a large-scale power system with 16 machines and 68 buses.