Justification of effective reactive power reserves with respect to a particular bus using linear sensitivity

Y. H. Choi, S. Seo, S. Kang, B. Lee

Research output: Contribution to journalArticlepeer-review

39 Citations (Scopus)


A constant reactive power (Q) reserve (CQR) is measured by the difference between the maximum reactive power generation and its current. However, all reactive power sources must not affect the entire power system when severe contingencies occur. Thus, generators must be evaluated as to whether or not they will have an impact on the maximum permissible loading of buses. This definition considers some generators to still have reactive power reserves when the system faces voltage collapse. This remaining reactive power reserve, although available, cannot be used in an arbitrary manner. This paper proposes the concept of an effective reactive power reserve and it is calculated on the basis of a sensitivity analysis. The computed reactive power reserve is analyzed using static and dynamic simulations in bulk power systems.

Original languageEnglish
Article number5783533
Pages (from-to)2118-2124
Number of pages7
JournalIEEE Transactions on Power Systems
Issue number4
Publication statusPublished - 2011 Nov

Bibliographical note

Funding Information:
Manuscript received July 01, 2010; revised October 27, 2010 and February 22, 2011; accepted April 14, 2011. Date of publication June 02, 2011; date of current version October 21, 2011. This work was supported by KESRI, which is funded by Ministry of Knowledge Economy. Paper no. TPWRS-00528-2010. The authors are with the Department of Electrical Engineering, Korea University, Seoul 136-713, Korea (e-mail: leeb@korea.ac.kr). Digital Object Identifier 10.1109/TPWRS.2011.2151212


  • Effective reactive power (Q) reserve (EQR)
  • particular bus
  • reactive power reserve
  • sensitivity
  • voltage stability

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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