An improved SSSC-based power flow controller design method and its impact on torsional interaction

► An improved method of designing an SSSC-based power flow controller is presented. ► Faster-responding power flow controllers can be achieved with the improved design approach. ► Faster acting constant power flow controllers would be preferable in SSR-susceptible situations. This paper presents an improved method of designing a closed-loop AC power flow controller. The paper further examines the impact of this improved SSSC-based power flow control on the damping of the subsynchronous torsional modes of a turbine-generator. Both the constant power and constant angle modes of power flow control are considered; in each case the influence of the controller design on torsional mode damping is examined over a range of operating conditions.