Life estimation of gear transmission unit in a turbine generator set due to short circuits

Abstract

This paper is concerned with the dynamic analysis of a gear transmission system in a turbo generator set and life estimation of the gears due to short circuits in the generator. The dynamic analysis of a turbo generator set is first briefly outlined to determine the torsional natural frequencies and mode shapes. An equivalent three mass system is derived for obtaining the transient response. The description of torque generated due to short circuits in the generator is then briefly presented. The response obtained as a function of time due to a sudden short circuit is then presented. Using a typical turbo generator set, the performance of gears in the transmission unit under normal torque conditions is first studied regarding their satisfactory performance. The transient response of the gear box is then taken into account to determine the number of electrical short circuits the turbo generator set can withstand. The methods used in this analysis are briefly described during the procedure.