Performance modeling and analysis of a single-shaft closed-cycle gas turbine using different operational control strategy

In the last few years, one considerable factor for the viability and interest in closed-cycle gas turbine systems for nuclear or conventional power plant application is its potential to maintain high cycle performance at varying operating conditions. However, for this potential to be realised, more competitive analysis and understanding of its control strategy is importantly required. In this paper, the iterative procedure for three independent control strategies of a 40 MW single-shaft intercooled-recuperated closed-cycle gas turbine incorporated to a Generation IV nuclear reactor is been analysed and their performance at various operating conditions compared. The rationale behind this analysis was to explore the different control strategy and to identify potential limitations using each independent control. The inventory control strategy offered a more viable option for high efficiency at changes in ambient and part-load operations, however, operational limitations in terms of size and pressure of inventory tank, rotational speed for which the centrifugal forces acting on the blade tips could become too high, hence would affect the mechanical integrity and compressor performance. The bypass control responds rapidly to load rejection in event of loss of grid power. And more interestingly the results showed the need for a mixed or combined control instead of a single independent technique, which is limited in practice due to operational limits.