Slow coherency based cutset determination algorithm for large power systems

Guangyue Xu, Vijay Vittal

Research output: Contribution to journalArticlepeer-review

157 Scopus citations


This paper provides an integrated algorithm to identify a cutset for a large power system for the application of a slow coherency based controlled islanding scheme. Controlled islanding is employed as a corrective measure of last resort to prevent cascading outages caused by large disturbances. The large scale power system is represented as a graph and a simplification algorithm is used to reduce the complexity of the system. Generators belonging to the same slowly coherent group are collapsed into a dummy node, and a graph partition library is used to split the graph into a given number of parts. Some extra islands formed by the partition library are merged into their adjacent large islands and the original cutset of the actual power system is recovered from the highly simplified graph. A software package was developed to test the efficiency of the algorithm, and dynamic simulations were run on the WECC system to verify the effectiveness of the cutset obtained. The WECC system has more than 15000 buses and 2300 generators. Detailed steps to develop an islanding strategy for a specified contingency for a large system are described in this paper.

Original languageEnglish (US)
Article number5325878
Pages (from-to)877-884
Number of pages8
JournalIEEE Transactions on Power Systems
Issue number2
StatePublished - May 2010


  • Controlled islanding
  • Cutset identification
  • Dynamic simulation in the WECC system
  • Slow coherency

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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