Abstract

Today, cyclic operation is typical operational mode for large-capacity steam turbines, which results from the overall situation in the electricity market. Additional life consumption due to creep-fatigue interaction, wear and tear and corrosion in specific components are principle effects of cyclic operation. So far cyclic operation has not been practised in the 500 MW units of V-EG, but preventive analyses of additional life consumption of critical components help to identify weak points and to avoid forced outages. The authors report about their life-consumption analyses of the IP rotor of a 500 MW steam turbine. The presentation adresses collection of operating data and their generalisation in pattern cycles, calculation of thermal and mechanical boundary conditions, FEM modelling of the rotor, analysis of the stresses and their ranges and finally the life assesment. Altough the analysis of the specific turbine showed that no adverse efect with regarg to forced life consumption is expected for cyclic operation, the authors draw precise conclusions with regarg to enhanced creep monitoring.