Assessment of the congestion cost and the risk of curtailment associated with available transfer capability (ATC)

This paper presents a probabilistic method of assessing the congestion cost and the risk associated with available transfer capability (ATC). The goal is to provide accurate and realistic ahead-of-time information on the ability of interconnected networks to reliably increase power transfer between geographical zones or commercial entities. Existing methods determine online transfer capability for one set of system conditions and apply analytical safety margins. The proposed method is based on a DC optimal power flow (OPF) coupled with Monte-Carte simulation of uncertainty on forecasted system conditions. It assesses, for incremental levels of simultaneous transfers, the probability of transaction curtailment and the congestion cost in each zone and for each transaction using the concept of locational marginal pricing. Case study results illustrate the impact of uncertainty on ATC and on the associated cost and risk, providing essential information to system operators and marketers. In future work, extension to active-reactive power transfers is being considered