Weighting function selection for H∞ based power system stabilizer design

Despite much progress in applying modern control technology to power system stabiliser (PSS) design with many different suggested PSS structures, many utilities still prefer a conventional PSS structure. The reasons may include ease of on-line tuning and lack of assurance on the stability related to some adaptive or variable structure schemes. Previously developed H_∞ and related design methods lead to fixed-structure and fixed-parameter yet robust controllers. Their applications in other areas have showed great potential. In Asgharian (1994) and Chow et al. (1990), some investigations on applying H_∞ methods to the PSS design are also presented. Both papers reported the importance and the difficulties in the selection of weighting functions for such design. In addition, the systems studied in both papers were restricted to single-(or two identical) machine infinite-bus power systems. This gives the author the motivation to study (1) a simple and effective way of selecting weighting functions; and (2) applying H_∞ method for multi-machine power system PSS design. In this, the author reports a study on the first problem for single-machine infinite-bus systems and this can also be extended to multi-machine power systems