Damping of power-system oscillations with the application of a GUPFC

FACTS devices might be successfully applied in power-system dynamics; however, appropriate control is a precondition for this. Some attempts were already made in searching of proper control strategies, but mainly according to local parameters and only for simple FACTS devices with only one controllable parameter. In this paper we present a control strategy for a GUPFC with multiple controllable parameters that is based on the energy function of a whole electric-power system and thus considers global parameters. The basis for the implementation of such a strategy that is proposed in this paper is to know the energy function of a power system that includes GUPFCs. Already-known energy functions that proved to be suitable for an electric-power system do not include such a device. Therefore, in this paper an energy function that considers the GUPFC´s action in the form of a supplement to the already-known structure-preserving energy functions was constructed. The application of proposed control strategy was used in numerical example of damping of power-system oscillations after the fault clearing. The results show that the magnitudes of the GUPFC´s series-injected voltages remain set to their maximum values and that only the angles of these voltages change, similar to the ldquobang-bangrdquo control strategies proposed for some other FACTS devices.