A comparison of the AC and DC power flow models for LMP calculations

Thomas J Overbye, Xu Cheng, Yan Sun

Research output: Contribution to journalConference articlepeer-review


The paper examines the tradeoffs between using a full ac model versus the less exact, but much faster, dc power flow model for LMP-based market calculations. The paper first provides a general discussion of the approximations associated with using a dc model, with an emphasis on the impact these approximations will have on security constrained OFF (SCOFF) results and LMP values. Then, since the impact of the approximations can be quite system specific, the paper provides case studies using both a small 37 bus system and a somewhat larger 12,965 bus model of the Midwest U.S. transmission grid. Results are provided comparing both the accuracy and the computational requirements of the two models. The general conclusion is that while there is some loss of accuracy using the dc approximation, the results actually match fairly closely with the full ac solution.

Original languageEnglish (US)
Article numberCSMDE01
Pages (from-to)725-734
Number of pages10
JournalProceedings of the Hawaii International Conference on System Sciences
StatePublished - 2004
EventProceedings of the Hawaii International Conference on System Sciences - Big Island, HI., United States
Duration: Jan 5 2004Jan 8 2004

ASJC Scopus subject areas

  • Computer Science(all)

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