Identifying inter-area oscillations using Hilbert-Huang trasformation for improving damping through PSS

Hilbert-Huang transform (HHT) is applied to wide area measurement system (WAMS) data in order to identify inter-area oscillations present in the system. HHT is used to extract instantaneous frequency of multicomponent signal using Empirical Mode Decomposition (EMD) and Hilbert transform. Upon identification of oscillatory modes, these oscillations are damped through power system stabilizers (PSS) connected to the exciters of the generators. Conventional PSS uses a local signal like generator speed deviation or real power output deviation. Here, two signals have been considered for PSS. The first signal is local signal that is the speed deviation of the generator at which PSS is connected. The second signal is a global signal. Several global signals have been tested. The global signals used are the remote rotor speed deviations, tie-line real power and voltage magnitude. The proposed method has been applied to two-area test system and the simulation results are presented.