Rated speed (n) = 3600 MVA rating of the Generator = 586 MVA Number of masses = 7: (HPa , HPb , Coupling1, LPa, LPb, Coupling2 and Generator) Number of Torsional modes= 6 Mechanical frequencies as calculated by the manufacturer: 23.4, 34.2, 145.53, 183.26, 223.84, 242.30 Hz Example 3: Shaft System of a Single Shaft Combined Cycle Gas Turbine with SSS Clutch Torsional data of the turbine-generator Operation Mode 1: Steam Turbine is Engaged Mass Rotating Mass Inertia Moment of Shaft Damping Power Section No. Constant H Inertia Stiffness constant Fractions MW.s/MVA J Constant of Turbine (s) [ton.m²] K [pu Section(s) between [pu] Masses speed] (i) [pu torque/rad] 1 Gas Turbine 0.6 0.869 0.25 37.25 2 Generator -- 1.428 0.02 31.31 3 SSS Clutch -- 0.7 0.1 27.66 4 Steam T Section 1 .25 1.427 0.2 17.78 5 Steam T Section 2 .15 0.176 0.2
Rated speed (n) = 3600 MVA rating of the Generator = 586 MVA Number of masses = 7: (HPa , HPb , Coupling1, LPa, LPb, Coupling2 and Generator) Number of Torsional modes= 6 Mechanical frequencies as calculated by the manufacturer: 23.4, 34.2, 145.53, 183.26, 223.84, 242.30 Hz Example 3: Shaft System of a Single Shaft Combined Cycle Gas Turbine with SSS Clutch Torsional data of the turbine-generator Operation Mode 1: Steam Turbine is Engaged Mass No. Rotating Mass Section Power Fractions of Turbine Section(s) [pu] (i) Inertia Constant H MW.s/MVA (s) Moment of Inertia J [ton.m²] Shaft Stiffness Constant K between Masses [pu torque/rad] Damping constant [pu speed] 1 Gas Turbine 0.6 0.869 0.25 37.25 2 Generator -- 1.428 0.02 31.31 3 SSS Clutch -- 0.7 0.1 27.66 4 Steam T Section 1 .25 1.427 0.2 17.78 5 Steam T Section 2 .15 0.176 0.2