Robust pole placement versus root-locus approach in the context of damping interarea oscillations in power systems

The merits of a robust low-order pole-placement method of damping-control design over a conventional root-locus method are discussed: both being aimed at providing adequate damping against interarea oscillations. The design is based on a weighted and normalised eigenvalue-distance-minimisation method (WNEDM) to obtain damping controllers employing superconducting magnetic-energy-storage (SMES) devices in a study system. The WNEDM-based control guarantees adequate damping in the prefault and postfault cases. The damping performance of the controllers is compared with that obtained by the root-locus technique. The results show that the WNEDM-based control is preferred over root-locus-based control when the control efforts in each are the same.