Determination of Optimal Start-up Curve for Steam Turbine Unit Considering Centrifugal Stress

Abstract

This paper concerns the optimal start-up schedule problem of steam turbine unit. Modelling of start-up process synthesizes the energy balance in turbine unit, depiction of control system, calculation of stress and damage. Quantitative analysis is made in the view of model feature, centrifugal stress’s effect, correction to the theoretical schedule and feasible space. Based on the synthetic model of turbine start-up schedule, a nonlinear unitary quadratic function is proposed and solved as the trajectory to improve start-up efficiency. Finally, the cold start-up of a domestic 300MW steam turbine unit is taken as a simulation example to prove the capability of this nonlinear start-up curve. Without violating the stress limit strictly, although the desired time improvement is only 6.35%, it still has important significance in practical thermal engineering, especially in the aspect of energy saving.