  In this article, we present a new methodology to identify if forced
oscillation sources are generated in excitation systems or in turbine
governors. In this context, we propose to harness the information that the
dynamic state estimation (DSE) provide to be able to apply a dissipating energy
flow (DEF) method. The measurements that the phasor measurement units (PMUs)
provide are used to estimate the internal states of different generators
connected to the same bus. Here, it will be considered that the PMU at the
point of connection is only capable of measuring the voltage phasor and the
total current phasor. Therefore, the current injection of the generator that is
causing the FO is an unobservable variable. To overcome this issue, event
playback is applied to simulate the model's response and a comparison between
the DSE of multiple generators is made. Finally, when the faulty generator is
identified, we compute energy functions for the mechanical control loop and for
the excitation control loop. The sign and rate of these energies determine the
source of the oscillation, allowing that the FO can be located. Simulated
signals are used to show that the proposed method provides a systematic
methodology for identification and location of power systems forced
oscillations than even could be non-stationary signals.
