BP 743, La Marsa, Tunisie

e-mail: hafedh.ateb@ept.rnu.tn

Department of Electrical Engineering

Michigan State University

East Lansing, Michigan, USA

This paper presents a stability assessment method for a power system differential-algebraic model, which takes into account the discontinuous effects of hard limits and equipment outages-induced transitions. Hard limits are associated with actions of operator control and protective devices. These hard limits do not cause immediate enablement or disablement of a particular control, and thus a time delay is associated with them. The taxonomic approach for systems with discontinuities in [1], not only neglects these time delays, but also requires a full time simulation based stability assessment.

A new Epoch Based Trajectory Stability Assessment Method along with a diagnostic procedure for systems with discontinuities are proposed. The Epoch Based Stability Assessment Methodology is aimed at assessing asymptotic stability within time intervals free of hard limits transitions where the stability assessment requires testing for quasi equilibria , limit cycles and trajectories within each epoch without time simulation, rather than attempting to study stability of the entire trajectory. The Epoch Based Stability Assessment Method is based on a trajectory simulation method implemented by [2] that does not require time simulation in , but only computes the quasi equilibria for each epoch for [3].

The methodology presented in this paper takes into account the effects of discontinuities, requires almost no time simulation, and yet may ultimately provide the diagnostic information obtained by repeated mid-term simulation of the contingency or operating change.