Wide-area measurement-based fault tolerant control of power system during sensor failure

• An algorithm is proposed for state estimation in power system when a subsystem is unobservable.
• A new method is proposed to find the best subsystem in power system for augmenting with the faulty subsystem to reconstruct the faulty signals.
• The fault-tolerant control switches to the appropriate observer gain using a look-up table immediately after the fault is detected.
• Effectiveness of the proposed method is validated under different fault scenarios in IEEE 14-bus test case.

Wide-area measurement systems (WAMS) have been used in power systems for centralized control purposes. One of the most important factors in the wide-area monitoring and control of power systems is availability of sensor measurements. Sensor failure can be called either a communication lost between sensor and controller or failure of a sensor itself. This paper, addresses fault tolerant control (FTC) of power systems 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 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 robust control of power systems. IEEE 14-bus test case is selected as a benchmark in transient analysis to show effectiveness of the proposed method. Simulation results show that the introduced approach works as intended.