Determination of the Permissible Range of Turbogenerators Non-Nominal Operating Modes at Thermal Power Plants

Turbogenerators of Ukraine thermal power plants have practically exhausted their service life, but their complete replacement is impossible in the coming years. The problem is aggravated by the fact that currently these turbogenerators not only produce electricity, but also solve the task of maintaining the nominal parameters of electrical networks during periods of peaks and dips in energy consumption. Such regimes cause their accelerated wear. In order to ensure the reliability of turbogenerators, it is necessary to understand in which non-nominal modes they can work under the condition of minimal additional load on the stator core fastening mechanical elements, in which the most defects were found during operation and repairs. Such studies were carried out for the tightening prisms of the stator core. The influence of the mode change was analyzed by the change in vibration on the body and on the bearing supports of the turbogenerator when its active power was reduced to 70%, 50% and 30% of the nominal one. Using the Solid-Works software complex, the distribution of mechanical stresses in rigid tightening prisms was determined. On the basis of these data, for the modes of reducing the turbogenerators load with a capacity of 200–300 MW, the intervals of permissible unloading are recommended under the condition of minimum mechanical stresses in the stator fastening elements.