Co-Ordinated Governor/Exciter Stabilizer Design in Multi-Machine Power Systems

This paper describes the application of multi-variable control design methods to the problem of designing co-ordinated stabilizers in a multi-machine environment. Linear state space methods are used to design co-ordinating stabilizing inputs for the exciter and governor loops, based on a number of local outputs. The dynamics of the multi-machine power system are taken into account by determining a dynamic equivalent model of the power system as seen from the transformer bus of the design generator. This is accomplished using identification techniques as described in a previous paper[2]. The generator equations are linearized and combined with this dynamic equivalent of the remainder of the power system, resulting in a reduced order representation of the combined system. Linear optimal control methods are then used to determine the co-ordinated controller. The effects of nonlinearities are taken into account by experimenting with different cost function weightings. The method is demonstrated by applying it to a generating station in an example 63 bus power system with a total of 59 generators represented.