Modelling and control of a 180-MW power system

This paper describes the modelling of the power and voltage control loop of a thermal power plant of 180 MW. The modelling is based upon full-scale measurements at the Flevo power plant of the PGEM. A relatively simple 5th order mathematical model of one unit for several working points has been developed. Based on this model an analysis is made of the existing controller structure and an improved voltage control system is designed. The design method is based on state-feedback technique and pole placement. By means of computer simulations in an extended non-linear model of this unit including the grid, the existing and the new-developed control are compared. To guarantee a close relationship with the real system, a two-generator model is built, using the extended Heffron-Phillips model of a synchronous generator. The interaction in both control structures is measured. Field tests have been carried out.