Faults detection and mitigation in excitation control of synchronous machines in large-scale power grids

This paper presents a new decentralised fault detection and mitigation system for excitation control systems used in synchronous generators in power grids. The system detects and diagnoses faults in the basic components of the excitation control systems with high accuracy and in almost real time using fuzzy set theory. Once a fault is diagnosed, a mitigation action follows, where the signal out of the faulty component is replaced by an alternative signal generated by the fault mitigation system. The mitigation action ensures that the field excitation voltage and thus the terminal voltage of the affected generator are controlled in a way that pre-fault stability of the grid is maintained. The accuracy and effectiveness of the proposed scheme are verified through case studies performed on the IEEE 30 bus test system.