Effects of model uncertainty on security assessment in deregulated power systems

In this paper we address the issue of quantifying transmission security in a deregulated power market. In particular, we are interested in effects of model uncertainties on characterization of system security. The paper addresses two types of uncertainties: 1) structural uncertainties (e.g., line outages) are modeled by contingency scenarios (by utilizing the matrix inversion lemma in the constraint sets), and 2) perturbation of model parameters (by utilizing first-order perturbation matrix theory in the optimization criterion and the constraint sets). The paper embeds these considerations in an optimization procedure that checks if transmission security is maintained, and, when necessary, generates minimal corrections in existing contractual transactions that ensure security. Given our interest in real-time applications, we consider problem formulations based on convex optimization, thus assuring the solution existence and uniqueness. The paper proposes a convex form of a linearized AC power flow model to describe the transmission network. Model is applied on example standard 68-node New England/New-York interconnected power system.