Influence of a Synchronized Self-Shifting Clutch in a Single-Shaft Plant on the Torsional Behaviour of the Shaft Train in Case of Electrical Faults
Abstract Synchro-self-shifting clutches allow the construction of combined gas- and steam power plants as single-shaft systems, which are economically advantageous due to enhanced efficiency and the use of only one generator for gas- and steam turbines. However, problems occur concerning the question, how to calculate torsional stresses and take into account the operation of the clutch in case of electrical faults. The article presents calculations of shaft and coupling torques as functions of time carried out by different methods in one exemplary case of faulty operation for a 351MW/228MW combined gas and steam single-shaft plant The clutch is modelled by a nonlinear torsional stiffness. The calculations show extremely strong impacts of torque inside the clutch due to intermittend engagement and disengagement processes. However, taking additionally into account damping influences inside the clutch one obtains no significant deviations from the results of a calculation for rigid couplings instead of the clutch.