A simplified nonlinear controller for transient stability enhancement of multimachine power systems using SSSC device

• New formation of SSSC controller is derived using Lyapunov theory.
• High order observer is used to estimate unavailable signals required to implement the control.
• Proposed nonlinear controller can be easily implementable in real-time.
• Impact of DFIG after large disturbances with the presence of SSSC in power system has been investigated.
• Results show that our method gives best damping oscillations.

In this paper, a simplified nonlinear method is proposed to enhance the transient stability of multimachine power system by using a Static Synchronous Series Compensator (SSSC). The rate of dissipation of transient energy is used to determine the additional damping provided by a SSSC. The proposed algorithm is based on the direct Lyapunov method. The simplicity of the proposed scheme and its robustness with respect to large disturbances constitute the main positive features. Simulation results in the case of 3-machines power system show the effectiveness of the proposed method under large disturbances (3-phase and single phase short-circuits).