Damage to Steam Turbine Rotors Due to Asynchronous Connections of Electric Generators to the Unified Power System

Abstract

The article aims to contribute to the ongoing study of damage to steam turbine rotors resulting from asynchronous connection of electric generators to the unified power system. At the present time, the assessment of the residual life of steam turbine equipment is based on the study of the degradation of the mechanical properties of steels and the analysis of the thermal stress state. The aim of this work was to determine the impact of such vibrations on the mechanical proper-ties of rotors and their damage. This goal was achieved by solving the following tasks: develop-ing a 3D model of the K-1000-60/3000 LMZ turbine unit shaft based on design documentation; calculating the stress-strain state of the shaft resulting from asynchronous connections using fi-nite element analysis; and evaluating the level of metal damage in the rotors due to torsional vi-brations. The developed mathematical model used a classical approach, replacing the working blades and bandage fastenings with concentrated masses and moments of inertia. The most im-portant results are the calculated rotor damages that occur due to asynchronous connection of the turbogenerator to the unified power system with a synchronization angle of 30°. The greatest damage to the rotor metal was found in the shaft section between the steam turbine and the elec-tric generator. The significance of the results obtained is that the use of this data will improve methods for assessing the remaining life of turbogenerators. This, in turn, will improve the relia-bility and safety of power plant operations.

Keywords

• steam turbine
• rotor
• asynchronous connection
• torsional vibrations
• stress-strain state
• damage.