Power-system stabilizer (PSS) design by probabilistic sensitivity indexes (PSIs)

A probabilistic power system stabilizer (PSS) design considering multioperating conditions is proposed in this paper. Under the assumption of normal distribution, the conventional eigenvalue sensitivity analysis is extended to a probabilistic environment by describing the statistical nature of eigenvalues as expectations and variances. Two probabilistic indexes derived from the sensitivities of eigenvalue expectations and variances are introduced to the PSS site and parameter selection. The robustness of the system can be guaranteed because wide range of the load variation has been taken into account in probabilistic representation. The effectiveness of the proposed PSS is demonstrated on a 3-machine system by probabilistic eigenvalue analysis and transient response simulation.