Development of a model for the simulation of combined cycle power plants during reception tests.

CARLOS SICCATTO,; ERICA CORREA; PABLO ARENA

Buenos Aires, Argentina

Congreso; Escuela de Estudios Energéticos.EdEE; 1999

Development of a model for the simulation of combined cycle power plants during reception tests.

The aim of this work is the development of a simulator of a thermal power plant working with a combined cycle, which is being built in Buenos Aires (Argentina). The simulator will be used as a tool during the reception tests of the cycle, and it represents the physical model of the plant. The main components of the plant are the two turbogas units, two Heat Recovery Steam Generators (HRSG), a three sction steam turbine, and a surface condenser with open-loop refrigeration. The HRSG units have three pressure levels, vertical flow and a reheating unit without post-combustor. Each one of the turbogas has a nominal power of 254 MW when burning natural gas and 262,6 MW when gas oil is used. Before the building of a new plant starts, the designer calculates all the properties of the different flows in the plant (steam, water, air, hot gases, fuel), at different loads and operation conditions. This data, together with the thermal balance of the plant constitute the thermal kit (ABB, 1979), and it is a very useful information source for developing a simulation model. After the building is finished, a set of tests must be performed in order to assure that the technical conditions specified in the contracts have been achieved. The main scope of these tests is that of verifying that the different components behave as expected, and that certain parameters that characterize the plant (e.g. the efficiency, the specific consumption, etc.) reach the values specified at different loads and operation conditions. A simulation model is a very useful and powerful tool that can assist while carrying these tests, because allow the owner to know how the plant should behaves in the conditions the tests are being performed.             For the development of the simulation model, operative data extracted from the thermal kit for each flow at different loads have been used. The numerical code has been written using EES Engineering Equation Solver, Version 4.10. The model is based in numeric equations from Spencer Cotton & Cannon (1974) method for the determination of the performance of the different sections of the steam turbine. For the estimation of the pressure at the steam extractions the Stodola Ellipse has been used. Key words: Simulation, models, reception tests, combined cycle, rational use of energy.