IAO mode coherence estimation utilizing enhanced-EMD technique and Correlation analysis

This paper presents an alternative method for estimating coherence of Inter-Area Oscillation(IAO) mode using Enhanced Empirical Mode Decomposition(E-EMD) technique and Correlation analysis(CA). It firstly extracts the components associated with the objective inter-area modes from each tie-line active power signal by utilizing the E-EMD techniques. Then the cross-correlation coefficients resulted from correlation analysis of these time-domain components are used to determine the coherence indexes among groups or generators for the IAO modes. This proposed method is more intuitive than spectral correlation analysis for demonstrating the phase relationship. A random time-varying load model is established by the Python programming tool of PSS/E in order to simulate the operating environment in the real world. The case studies have been carried out on New England 39-bus system and a simplified system of Southeastern Australian power system, and the results show that the proposed algorithm is effective.