Determination of an accurate dynamic security constraint with applications in market dispatch

This paper proposes the inclusion of transient stability constraints in generation dispatch algorithms used in electricity markets to ensure dynamic security. The proposed security constraint is derived by applying a non-linear surface fitting technique to a database generated off-line. The technique used has two key features that enables the derivation of an accurate transient stability constraint with a relatively short computing time compared to other comparable methods. One feature is that it uses a linear estimation technique to estimate a non-linear function by means of a non-linear transformation. The second important feature is that it employs an implicit technique to gain significant reduction in computing burden. The potential of the proposed method is demonstrated using the New England 39 bus system and a larger power system with 470 buses. The security constraint derived for the New England 39 bus system is used in an Optimal Power Flow (OPF) program for market clearance. The Locational Marginal Prices (LMP) obtained from the OPF are further analyzed to determine the component of LMP due to Dynamic Security.