Application of superconducting magnetic energy storage unit on damping of turbogenerator subsynchronous oscillation

A systematic approach is used to design a controller for a superconducting magnetic energy storage (SMES) unit to improve the torsional modes damping of a turbogenerator. To suppress the unstable torsional oscillation, a proportional-integral-derivative (PID) controller is employed to modulate the power input/output of the SMES unit according to generator speed deviation. The gains of the proposed PID controller are determined by the pole assignment method based on modal control theory. Eigenvalue analysis of the studied system shows that the PID controller is quite effective over a wide range of operating conditions. Computer simulations using the nonlinear system model are also performed to demonstrate the damping effort of the proposed controller under disturbance conditions