Dynamic Characteristics Analysis For Key Components Of Large Hydro-generator

With advances in motor design and manufacturing technology, the capacity of largehydro-generator is increasing; meanwhile, the vibration problem of the unit also becomesincreasingly prominent; thus, the design of hydro-generator needs higher requirements. Theshaft stability and dynamic characteristics of unit are important indicators of safe operation ofthe unit; those not only directly affect the operation quality of unit, but also affect the life ofthe unit. In order to avoid resonance phenomena of hydroelectric generation, mechanicalcalculations of megawatt hydro-generator are performed for its stable operation. Because thestability of generator rotor system has a large influence on the reliability of power supply andgrid-connected stability, the generator shaft must have a high bearing capacity and stiffness. Areasonable critical rotational speed must be designed for the rated speed of generator awayfrom the critical speed, to avoid resonance phenomena.This paper outlines the necessity of developing hydro-electric power. To deepen theunderstanding of development history of megawatt hydro-generator, the developmentbackground and domestic and foreign research status of megawatt hydro-generator arepresented. This paper takes the megawatt hydro-generator as the study. Three main factorscaused the unit vibration of hydro-generator are introduced in detail, and they are mechanical,electromagnetic, hydraulic factors, respectively. The phenomena of vibration caused byvarious factors are separately discussed, and the methods of reducing or eliminating thevibration are proposed. The focus of this paper is calculating the dynamic characteristics byusing formula calculation. This paper focuses on mechanical calculations of the shaft,including bearing capacity, all kinds of mechanical stress, safety factor, deflection, criticalspeed, and strength calculation of shaft and results validation. According to the calculationresults, characteristics of shaft are analyzed, to provide theoretical basis for the design andstability analysis of hydro-generator.Compared with standard data, the data of calculation results verifies the rationality of thedesign of hydro-generator shaft and the correctness of the calculation method, whose resultsprovide the basis for the design of the hydro-generator shaft. In addition, in terms of therelationship between the mechanical parameters of the generator, a method of optimizingeffective parameters is put forward for improving generator structure, so as to improve thereliability and stability of rotor system and even power system.