PREDICTING TRANSIENT INSTABILITY OF POWER SYSTEMS BASED ON HYBRID SYSTEM REACHABILITY ANALYSIS

This paper shows a novel method for predicting transient instability of power systems based on reachability analysis of hybrid systems. The analysis is performed by computing reachable sets of unsafe sets in nonlinear hybrid automata that represent both continuous electro-mechanical dynamics of generators and discrete operations by relay devices. The unsafe sets here are subsets of system states in which power systems show unacceptable operations such as stepping-out of generators. Then the transient instability of power systems can be estimated by investigating whether a system state exists in the reachable sets or not. The estimation is possible at any onset of accidental faults such as line and plant trips. This paper demonstrates the proposed method through an analysis of single-machine infinite bus system.