  This paper addresses Fault Tolerant Control (FTC) of Large Power Systems
(LPS) subject to sensor failure. Hiding the fault from the controller allows
the nominal controller to remain in the loop. We assume specific faults that
violate observability of a subsystem, and we cannot rely on these faulty
subsystems when estimating states. We use a new method for reconfiguration
control of these faults that lead to unobservability of subsystems. The method
proposes augmenting a faulty subsystems with another subsystem(s) until a new
subsystem is achieved that is observable. Next, finding the best subsystems
among available candidates is considered and using structural analysis methods
and grammian definition, a complete algorithm is proposed for FTC of LPS. The
proposed approach is applied to the IEEE 14-bus test case and interactions are
considered in nonlinear form. Simulation results show that the proposed
approach works as intended.
