This paper presents the development of /spl mu/-power system stabilizer (PSS) based on the active power measurement to enhance damping characteristics of the single-machine infinite-bus system. The standard design procedure of the PSS requires the nominal structured model to be formulated. It is obvious that this linearized model loses some information and the designed PSS cannot ensure good damping of the electromechanical oscillations over a wide range of operating conditions. To avoid this the /spl mu/ synthesis in PSS design is proposed. The difference between the nominal model and real system are taken into account by the unstructured uncertainties. Simulation results have been obtained under various operating conditions to show that the proposed /spl mu/-PSS can provide a better damping of electromechanical oscillations over a wide range of operating conditions than the classical one.