It is nowadays a common understanding that, due to the uneven availability of the increasing renewable energies, operation of power generation plants and especially of combined cycles has to be more flexible and subject to more frequent starts than in the past. This phenomenon translates into an increased number of equivalent operating hours, with negative impact on maintenance intervals and operating costs. In addition, the optimization of start-up time, largely driven by initial components temperature, has become a key performance indicator for the profitability of such plants. 

The case study presented in this paper deals with a combined cycle power plant, commissioned on the early 2000s, currently operating daily for half of the year and occasionally for the other half, collecting about 150 warm and 30 cold starts per year.           

The application to the steam turbine of a Thermal Warming System (TWS) is analyzed in detail by assessing casing and rotor temperature distribution, in transient operation. The control algorithms, that allows maximizing the system effectiveness while safeguarding against possible issues due to uneven temperature distributions, are also discussed. The resulting increase in average starting temperature, as evidenced by online rotor temperature calculation, is then considered with respect to its benefits for maintenance optimization and plant profitability.


Steam Turbine Improved Operation and Maintenance by Thermal Warming System

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

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