SIMULATION OF THE LOAD FOLLOWING CAPABILITY OF A REPOWERED PLANT 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 hydro power stations to start-up thermal units. During the last ten years, some of the Italian thermal plants have been repowered with combined cycles by topping the existing steam sections with gas turbines. Aim of this paper is to investigate whether and how the black-start capability of power plants gas sections could be used to start up the steam sections. This would improve the speed and reliability of the early restoration procedure. For such a purpose, a numerical simulator has been built using the Lego modular code, which allows getting a deeper insight about all problems concerning the black start-up procedure. The paper presents the results obtained by means of the simulator, which includes an additional control system (load scheduler), designed to operate simultaneously both the gas and steam sections as a single plant, during the initial phases of the restoration process. This additional control system can be useful to assist the plant operators, by avoiding untimely trip of generators, as well as by limiting the stress of the components and by speeding the restoration process.