The Analysis And Optimization System For Large Steam Turbine Unit On Peak-load Operation Mode

Analysis and optimization on peak load operation mode for large capacity steam turbine unit are very important to ensure safety, reliability and economics of steam turbine unit during its startup and shutdown. In general, elevated temperature turbine equipment, such as, the high- pressure steam turbine rotor, is subject to a critical steam condition. Its fatigue life expenditure during startup will directly influence the safety and reliability of steam turbine unit. Furthermore, the large life expenditure of a component also increase maintenance cost and outfit cost in full-life of steam turbine unit. In this paper the mathematical model including three parts, safety analysis, economics analysis and optimization, has been established. Based on simplified calculation method of the temperature fields and thermal stress fields under nonlinear change of steam temperature for high-pressure steam turbine, a quantitative cost analysis model considering fatigue life expenditure of steam turbine rotor and consumed fuel during startup is presented. An objective function, orientated with rotor life expenditure cost and direct fuel loss cost, is analyzed and optimized. On the basis of aforementioned mathematical model an analysis and optimization software package for large capacity, which is implemented by means of object-orientated code Delphi steam turbine unit is developed in this paper. In order to verify the software a series of analysis and comparison for 200MW steam turbine units made in China are carried out. A good coincidence between analysis conclusion and practical situation can be observed.