Electromechanical Wave Propagation for Disturbance Arrival Time Assessment in Power Systems

Rotor angle instability in a power system can yield cascading failures and, eventually, blackouts. In the literature, recent studies investigate the propagation pattern of the Electromechanical Waves (EMWs) throughout the transmission system produced by rotor angle deviations. Interestingly, they show that the EMWs propagate with a velocity much smaller than the speed of light. Consequently, the EMW arrival time to buses should be considered as one of the disturbance analysis criteria and accounted for in the design of the power system control. However, in these studies, the EMWs are modeled under the assumptions of a uniform distribution of the generator inertias, and the voltages, the length of lines, and the line parameters in the entire power system are respectively equal to each other. This paper relax some of these assumptions in that it analyzes the EMW propagation by considering a nonuniform distribution of the generators' inertias throughout the transmission system while the generators' internal reactances and line reactances are accounted for. Simulations performed on the New England 39-bus 10-Machine system revealed that the EMW velocity is significantly reduced when the generator reactances are accounted for when the inertia distribution is based on the line admittances. Also, it shows the dependency of the EMW propagation on the disturbance frequency.