A single-input multiple-output excitation controller via eigenstructure assignment for damping the subsynchronous resonance of a turbogenerator

Abstract

Damping of subsynchronous resonance using a single-input multiple-output (SIMO) excitation controller is investigated in this paper. An eigenstructure assignment technique is applied to design this controller for suppressing various unstable torsional modes. Eigenvalue analyses under different loading conditions and a wide range of series capacitor compensations and digital simulations under a pulsed torque disturbance are performed to demonstrate the effectiveness of the proposed approach. Also, the proposed controller can be easily implemented by a multiple proportional-integral (MPI) controller with only the available speeds of the medium pressure turbine, the two low pressure turbines, and the generator machine as feedback signals. Using these feedback signals, the problems of resetting the reference values of feedback signals for different operating points and inadequate feedback signals introduced by unbalanced system conditions will not occur in a power system with the proposed controller.