This paper presents the dynamic-stability analyzed results of an offshore solar-concentrated ocean thermal energy conversion (SC-OTEC) system connected to an onshore power grid through undersea cables. The complete dynamic system equations of the studied SC-OTEC system are established under three-phase balanced conditions. A power system stabilizer (PSS) is designed using modal control theory to offer adequate damping characteristics for the synchronous generator of the studied SC-OTEC system. Steady-state characteristics of the studied system under different operating conditions and dynamic simulations of the studied system subject to different disturbances are both carried out. It can be concluded from the simulation results that the designed PSS can effectively enhance damping of the studied grid-connected SC-OTEC system under various disturbance conditions.