Dynamic stability improvement of four parallel-operated PMSG-based offshore wind turbine generators fed to a power system using a STATCOM

This paper presents the stability-improvement results of four parallel-operated offshore wind turbine generators (WTGs) connected to an onshore power system using a static synchronous compensator (STATCOM). The operating characteristics of each of the four WTGs are simulated by a 5-MW wind permanent-magnet synchronous generator while the onshore power system is simulated by a synchronous generator (SG) fed to an infinite bus through two parallel transmission lines. A damping controller of the proposed STATCOM is designed by using a pole-assignment approach to render adequate damping to the dominant modes of the studied SG. A frequency-domain approach based on a linearized system model using eigenvalue analysis is performed while a time-domain scheme based on a nonlinear system model subject to disturbances is also carried out. It can be concluded from the simulation results that the proposed STATCOM joined with the designed damping controller can effectively improve the stability of the studied SG-based onshore power system under various disturbance conditions.