Research On Online Monitoring System For Torsional Vibration Of Turbine Generator Sets

Due to the important task of achieving the strategic goal of "carbon peak and carbon neutrality," a large number of new power system technologies were used in the power industry,leading to a trend of increasing complexity in the overall power system structure.In addition,as the core component of power generation,the single-unit capacity of steam turbine generator sets continued to increase,and the rotor structure of the units became increasingly complex.Due to these factors,the risk of shaft torsional vibration in the units increased.Once torsional vibration failure occurred,it not only caused fatigue damage to the shaft system and affected the stable operation of the unit but also may have led to unplanned shutdowns and brought enormous economic losses.Therefore,researching online monitoring systems for torsional vibration in steam turbine generator sets had significant engineering application value.This article explored and solved relevant technical problems from the perspective of practical engineering applications,with the ultimate goal of developing a torsional vibration online monitoring system to ensure the stable and safe operation of the unit.Firstly,a simplified modeling method based on an equivalent blade group was proposed,which ensured sufficient accuracy while reducing the dimension of the matrix equation as much as possible,avoiding the difficulties caused by solving the multi-parameter finite element matrix and freeing up computational resources.Secondly,torsional vibration faults were classified into two types:impact and resonance,and several typical faults that were prone to serious torsional vibration in the shaft system were studied in detail.The mechanism,performance characteristics,and prevention and suppression methods of these faults were analyzed in-depth,providing a theoretical basis for the classification of torsional vibration fault types and the determination of dangerous cross-sections in the subsequent torsional vibration monitoring system.Then,based on the fatigue damage evaluation method of the shaft system under torsional vibration faults,a set of procedures for calculating the fatigue damage of the shaft system was formulated,mainly including the fitting of the S-N curve,the determination of dangerous cross-sections under different faults,and the fatigue life calculation using the rainflow method.Finally,based on the above research results and combined with a web visualization interface,a complete steam turbine generator unit torsional vibration online monitoring system was designed and developed,which covered shaft system simplified modeling,torsional vibration analysis algorithms,and software and hardware design and installation.It was successfully applied to a domestic 1750MW nuclear power unit,achieving fast and accurate diagnosis of shaft system torsional vibration faults and providing strong support for the safe and reliable operation of the unit.