Assessment of steady state stability of a multi-machine power system with and without a superconducting machine

The steady-state performance of a multi-machine system which includes a superconducting generator is examined. the PQR method for constructing the system matrix, which was developed for a single conventional machine, has been modified and extended to include several generating units, some of which are superconducting. This technique has been applied to obtain the system matrix of a multimachine network which includes hydro, nuclear, steam, and superconducting units. The eigenvalues and dynamic interactions in both the controlled and uncontrolled systems are analyzed. To examine the effects of the superconducting alternators, the results are compared with those obtained by replacing the superconducting generator with conventional machine. The results show that the introduction of a superconducting machine to a multi-machine system increases its steady-state stability limits. However, due to the low inherent damping of this machine, the damping of the rotor oscillatory mode is degraded. It is concluded that the results obtained form a useful guide for introducing the new machine into larger power systems. >