Simulation studies on mitigating subsynchronous resonance with coaxial double fed motor

With the rotor´s AC excitation characteristics, the double fed motor can realize free control of the rotational speed and the torque, so it has advantages on mitigating subsynchronous resonance (SSR). This paper proposes the method of using double fed motor for mitigating SSR for the first time. When double fed motor and generator are installed coaxially, the double fed motor can bring in damping torque to the shaft directly, so as to mitigate SSR. By analyzing the transfer characteristics of the damping torque attached to the shaft by coaxial double fed motor, as well as supplementary subsynchronous damping control strategy, it is indicated that this method can mitigate SSR in the closed-loop control effectively. Based on IEEE SSR first benchmark, simulation model about coaxial double fed motor for SSR mitigation is built. Simulation results show that the proposed coaxial double fed motor for SSR mitigation is effective.