Impact of weighting coefficients on the convergence rate of the steepest descent algorithm used for the design of an optimal power system stabilizer (OPSS)

This paper presents the impact of weighting coefficients on the power system stability, and on the convergence rate of the steepest descent algorithm used for the design of an optimal power system stabilizer (OPSS). A simple objective function integrating weighting factors and weighting coefficients takes into account all the critical operating conditions. The steepest descent optimization method based on eigenvalue sensitivity is used for the minimization of the objective function. It was found that the selection of suitable weighting coefficients is not straightforward and that trial and error method is needed. Simulation results show that the selection of weighting coefficients is critical and has a direct impact on the eigenvalue, the damping ratio, and the norm of the gradient of the objective function.