Identification of inter-area oscillations using wavelet transform and phasor measurement unit data

This paper presents a method for identification of the inter-area oscillations in power system by employing continuous wavelet transform (WT) with complex Morlet function. WT is implemented to decouple multi-component signals into the mono-component signals. The mono-component signals are represented as complex-valued signals. The corresponding parameters of oscillations such as the frequency and damping can be identified using the instantaneous amplitudes and phase angles of the complex-valued signals. The optimal values of Morlet parameters are obtained by minimization of the WT entropy. The performance of the proposed method is demonstrated by applying it to several simulated test cases and real power system data. The simulated test cases include a non-stationary test signal and two-area test system. The proposed method also implemented on measured data of Malin-Round Mountain tie-line power flow oscillation during 10 August 1996 event, and the results are compared with Prony method.