Electric Infstructure to Power a Digital Society

Several recent papers have introduced the concept of induced torque coefficients (ITCs). The concept of induced torque coefficients is essentially a generalization of the concept of damping and synchronizing torques to a multimachine, multimodal power system. This generalization allows the interactions between each stabilizing device and each machine in the system to be quantified for the purposes of a more systematic coordination of stabilizers (both PSSs and FACTS damping controllers) on a system-wide basis. In this process, a key feature is the ability to estimate, from the ITCs, the shift in system eigenvalues due to a perturbation in the gain of a stabilizer. Independently, others have developed techniques for the coordination of stabilizers based on the calculation of eigenvalue shifts from the residues. In this paper, it is shown that the eigenvalue shifts estimated by both these techniques are mathematically equivalent; the ITC approach, however, provides additional information.