Analysis of the inter-area mode oscillations using normal form method

In the deregulated power industry, the increasing number of power marketers and independent power generators increases the variability of power flow patterns in the transmission system, thereby reducing the ability of transmission planners and operators to predict the critical operating conditions and limits. Conventional linear analysis cannot account for many complex dynamic behaviors. As recognized by many researchers, the very nature of inter-area phenomena is not well understood and may include nonlinear interaction of the system oscillation modes. This paper presents some advances on the development of normal form method for the analysis of inter-area oscillations in complex power systems. Second-order analysis indicates that more frequencies of oscillation may have significant influence on the system response. This method is used to extend linear concept of participation factor to include 2nd-order modal affects on system dynamic behavior. The analysis and the procedure developed are tested on some IEEE test systems.