  In this paper, the simulation of the disturbance propagation through a large
power system is performed on the WSCC 127 bus test system. The signal frequency
analysis from several parts of the power system is performed by applying the
Wavelet Transform (WT). The results show that this approach provides the system
operators with some useful information regarding the identification of the
power system low-frequency electromechanical oscillations, the identification
of the coherent groups of generators and the insight into the speed retardation
of some parts of the power system. The ability to localize the disturbance is
based on the disturbance propagation through the power system and the
time-frequency analysis performed by using the WT is presented along with
detailed physical interpretation of the used approach.
