Stability Improvement of a Hybrid DFIG-Based and PMSG-Based Offshore Wind Farm fed to a SG-Based Power System Using a STATCOM

Abstract

This paper presents the stability-improvement results of a synchronous generator (SG)-based one-machine infinite-bus (OMIB) system with a hybrid doubly-fed induction generator (DFIG)-based and permanent-magnet synchronous generator (PMSG)-based offshore wind farm (OWF) using a static synchronous compensator (STATCOM). The operating performance of the studied PMSG-based OWF is simulated by an equivalent PMSG driven by an equivalent wind turbine (WT) while an equivalent DFIG driven by an equivalent WT through an equivalent gearbox is used to simulate the operating characteristics of the DFIG-based OWF. The hybrid OWF is connected to the point of common coupling (PCC) of the SG-based OMIB system through an undersea cable and an underground cable. The proposed STATCOM is connected to the PCC to supply the required reactive power to the SG-based power system. A frequency-domain approach based on a linearized system model using eigenvalue technique and a time-domain scheme based on a nonlinear system model subject to various disturbance conditions are both utilized to examine the effectiveness of the proposed control scheme. It can be concluded from the simulation results that the proposed STATCOM is capable of offering adequate damping characteristics to stabilize the studied OMIB system under various operating conditions.