Robustness Evaluation Of H ∞Power System Stabilizer

This paper investigates the effect of damping ratio zeta on the performance of Hinfin power system stabilizer (PSS). The bilinear transformation is used together with the Hinfin optimal control to design the Hinfin-PSS. Various zeta levels are obtained by varying the parameter |p
₁
| of the bilinear transformation as guided by a certain rule-of-thumb. The effect of the variation in the zeta on sensitivity S(s) and Input sensitivity R(s) functions are investigated. Performance comparison is also made between the nominal and worst operating conditions. Results show an improvement in the zeta as |p
₁
| is increased It is shown that |p
₁
| may not be set very high as this may compromise robustness.