Inclusion of higher order terms for small-signal (modal) analysis: Committee report - Task force on assessing the need to include higher order terms for small-signal (modal) analysis

Juan J. Sanchez-Gasca, Vijay Vittal, M. J. Gibbard, A. R. Messina, D. J. Vowles, S. Liu, U. D. Annakkage

Research output: Contribution to journalArticle

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This paper summarizes the work done by the Task Force on Assessing the Need to Include Higher Order Terms for Small-Signal (Modal) Analysis. This Task Force was created by the Power System Dynamic Performance Committee to investigate the need to include higher order terms for small signal (modal) analysis. The focus of the work reported here is on establishing and documenting the practical significance of these terms in stability analysis using the method of Normal Forms. Special emphasis was placed on determining and describing conditions when higher order terms need to be included to accurately describe modal interactions. Test cases were developed on a standard test system to demonstrate the application of appropriate indices to detect the occurrence of nonlinear interaction and hence the need for higher order terms in stability analyzes. The use of the higher order terms in the site selection for a damping controller is also documented.

Original languageEnglish (US)
Pages (from-to)1886-1904
Number of pages19
JournalIEEE Transactions on Power Systems
Issue number4
StatePublished - Nov 1 2005



  • Method of normal forms
  • Modal analysis
  • Modal damping
  • Modal frequency
  • Nonlinear modal interaction

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

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