Comparative analysis of accelerating power input and speed input robust power system stabilizers

The power system stability improvement by a robust Power System Stabilizer (PSS) using accelerating power and speed as inputs is investigated independently in this paper. The objective of the work presented in this paper is to design an accelerating power input robust PSS and a speed input robust PSS to damp low frequency oscillations arising out of small and large disturbances. The robustness of the PSS is ensured by placing all the eigen values within a specified contour in the s-plane. A nonlinear constrained optimization technique has been applied for tuning the PSS parameters with the objective of damping oscillations over a wide range of operating conditions to make the PSS robust. The design of PSS is validated by performing nonlinear simulations for small and large disturbances.