Simulation of the Load Following Capability of a RepoweredPlant During the First Phase of the System Restoration

摘要

The Italian restoration plan after a black out relies traditionally on the black-start capabilities of hydrornpower stations to start-up thermal units. During the last ten years, some of the Italian thermal plantsrnhave been repowered with combined cycles by topping the existing steam sections with gas turbines.rnAim of this paper is to investigate whether and how the black-start capability of power plants gasrnsections could be used to start up the steam sections. This would improve the speed and reliability ofrnthe early restoration procedure. For such a purpose, a numerical simulator has been built using thernLego modular code, which allows getting a deeper insight about all problems concerning the blackrnstart-up procedure. The paper presents the results obtained by means of the simulator, which includesrnan additional control system (load scheduler), designed to operate simultaneously both the gas andrnsteam sections as a single plant, during the initial phases of the restoration process. This additionalrncontrol system can be useful to assist the plant operators, by avoiding untimely trip of generators, asrnwell as by limiting the stress of the components and by speeding the restoration process.