Assessment of nonlinear interaction between nonlinearly coupled modes using higher order spectra

A. R. Messina, Vijay Vittal

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Higher order spectral analysis techniques are used to identify nonlinear interaction involving the electromechanical modes of oscillation in complex power systems. First, the presence and extent of nonlinear interactions between frequency components in oscillatory processes following large perturbations are identified using bispectrum and bicoherence analysis methods. Then, the strength and distribution of nonlinear couplings between frequency components is investigated using the phase relationships between spectral components. A case study with a 377-generator model of the Mexican interconnected system is used to illustrate nonlinear aspects arising from the nonlinear interaction of the different low-frequency inter-area modes. The results of the numerical simulations show that low-frequency modes may interact nonlinearly producing intermodulation components at the sum and/or difference frequency of the fundamental modes of oscillation. Such an identification can be used as a benchmark for validation of nonlinear analysis methods, and to reduce the burden associated with these methods.

Original languageEnglish (US)
Pages (from-to)375-383
Number of pages9
JournalIEEE Transactions on Power Systems
Issue number1
StatePublished - Feb 2005
Externally publishedYes


  • Nonlinear systems
  • Power system dynamic stability
  • Spectral analysis
  • Statistics

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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