Fault Tolerant Control of Power Systems in presence of Sensor Failure

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. NOMENCLATURE í µí¼¹ í µí²Š The power angle of the í µí²Š í µí²•í µí²‰ generator, in rad í µí¼” í µí±– The relative speed of the í µí±– í µí±¡ℎ generator, in rad/s í µí¼” 0 The synchronous machine speed, in rad/s í µí°· í µí±– The damping factor, in p.u. í µí°» í µí±– The inertia constant, in í µí± í µí±ƒ í µí±ší µí±– The mechanical input power, in p.u. í µí±ƒ í µí±’í µí±– ,í µí±„ í µí±’í µí±– Active and the reactive electrical power, in p.u. í µí°¸í µí±“í µí±– The equivalent EMF in the excitation coil, in p.u. í µí°¸í µí±ží µí±– ′ The transient EMF in the quadrature axis, in p.u. í µí°¸í µí±ží µí±– The EMF in the quadrature axis, in p.u. í µí±‡ í µí±‘í µí±œí µí±– ′ The direct-axis transient time constant, in í µí± í µí±¥ í µí±‘í µí±– The direct axis reactance, in p.u. í µí±¥ í µí±‘í µí±– ′ The direct axis transient reactance, in p.u. í µí°¼ í µí±‘í µí±– , í µí°¼ í µí±ží µí±– Direct and the quadrature axis current, in p.u. í µí°¼ í µí±“í µí±– The excitation current, in p.u. í µí±¥ í µí±Ží µí±‘í µí±– The mutual reactance between the excitation coil and the stator coil, in p.u. í µí°µ í µí±–í µí±— + í µí±—í µí°º í µí±–í µí±— The mutual reactance between the excitation coil and the stator coil, in p.u.