Robust PSS Parameters Design Using a Trajectory Sensitivity Approach

A new model for coordinated optimal design of power system stabilizers (PSSs) is proposed for damping low frequency power oscillation of interconnected power systems and enhancing overall performance of both transient and small-signal stability. In this model, a novel objective function is constructed using rotor speeds of generators in a post disturbed period. Trajectory sensitivity mapping technique is proposed to evaluate the approximate gradients of the objective function relative to the PSS parameters. With the gradients, conjugate gradient method is employed to assess the PSS parameters for minimizing the objective function. Two schemes of gradient formulation and optimization procedure are suggested and compared. The model and effectiveness of the method are verified by eigenvalue assessments and time domain nonlinear simulations on the IEEE four-generator and the ten-generator New England test systems.