Initial Concepts for Applying Sensitivity to Transfer Capability

The available transfer capability indicates how much interarea power transfers can be increased without compromising system security. That is, the available transfer capability is the total transfer capability minus the base case transfer together with adjustments to allow some margin of safety. Much of the experience in computing transfer capabilities concerns line #ow limits and uses DC load #ow power system models. However, in some cases the total transfer capability is limited by voltage magnitude or voltage collapse and this paper mainly addresses these voltage limits. Accurate determination of these voltage limits requires nonlinear power system models and the continuation computation described below. Once the total transfer capability is computed under one set of operating conditions or assumptions, it is useful to determine the effect on the total transfer capability of varying the operating conditions or assumptions. We suggest sensitivity methods for quickly estimating the effect on the transfer capability of varying the operating conditions, assumptions or data.