Turbine-generator shaft torsional vibrations resulting from transmission line transients

In 2007 a working group (#4) was established by the Generator Subcommittee of the Electric Machinery Committee to study and consolidate recent findings related to torsional effects on turbine-generator shaft systems caused by certain types of transmission system transients. This paper will outline some of the findings of that working group. It will provide some background relating to previous studies and experience with turbine- generator torsional vibration but will concentrate on system transients that result in significant torsional impulses on shaft systems. Problems associated with capturing the waveforms of the transients as well as quantifying the magnitude of the resulting torsional stress on the tubine-generator shafts will be discussed. Experience in modeling both turbine-generators and associated transmission systems will be provided.