Shaft models of subsynchronous oscillation in power system

Abstract

Based on a domestic 300 MW turbine generator shaft, finite element model is established with ANSYS and with which modal analysis is conducted to solve the natural frequencies of torsional vibration. Multi-lumped mass model is established with the discretization of continuous turbine generator shaft and simple lumped mass model is obtained with K/M ratio sensitivity method. Natural torsional vibration frequencies of the lumped mass modes are solved by using eigenvalue analysis. Possibility of subsynchronous oscillation is estimated and the accuracy of the three models are compared by natural frequencies of torsional vibration. The results show 175 shaft segments model (multi-lumped mass model) is more practical on account of less computations and easier access to simulation.