Robust design of fixed-parameter power system stabilisers over a wide range of operating conditions

The approach of M.J. Gibbard (see Proc. IEE, vol.135(4), pt.C, p.276-84, July 1988) for the coordinated design of power system stabilizers (PSSs) in multimachine power systems is further developed. The aim of the approach is to provide, through the action of the stabilizer, an electrical damping torque proportional to speed perturbations, i.e. Δ_di(s)=D_i Δω_i(s). The stabilizer network is designed to compensate for the torque-reference voltage transfer function ΔP_ei(s)/Δν_ri (s). It is demonstrated that this transfer function remains more or less invariant over a wide range of operating conditions. As a result, it is shown that the design approach yields fixed-parameter PSSs which are robust over a wide range of conditions