STRATEGIA DALSZEJ EKSPLOATACJI I OBSŁUGI TURBIN PAROWYCH Z UWZGLĘDNIENIEM ELASTYCZNYCH WARUNKÓW PRACY BLOKU WĘGLOWEGO

In order to ensure the safe operation of the power system in Poland and to maintain energy production from old coal-fired power plants, it is required to develop a strategy for further operation of the units in conditions of increased flexibility. The article focuses on the critical element of the turbine, which is the rotor high-pressure part. The methodology of the forecasting of crack propagation and the increase in fatigue-creep wear was presented, and the probability of failure in the following years was estimated. The development of the identified phenomena depends on the stress level during start-up, therefore it was selected in such a way as to ensure the safety of the turbine's operation during the assumed period of 13 years. For a longer service life of 20 years, the method of selecting the optimal time for preventive maintenance based on a risk analysis was additionally presented. An algorithm for online stress monitoring is also described, taking into account the variability of the heat transfer coefficient. It can be also transformed into a real-time stress level control system. Through the developed tools, it is possible to obtain the desired increase in stresses during start-up. The conducted research allows for the presentation of a strategy for further operation and maintenance of the turbine, which can be adapted to a specific real unit.