An efficient method of calculation for transient stability ATC in longitudinal power systems

Recently, in the process of deregulation, fast evaluation of ATC (Available Transfer Capability) has been one of the most important problems in regards to the effective use of networks. Especially, in Japanese power systems which have small capacity of tie-lines. Fast and accurate evaluation of the tie-line ATC is one of objectives that should be achieved for wide-area power transactions. Therefore, we propose an efficient calculation method for the tie-line ATC with transient stability constraints. In this paper, we first focus our attention on characteristics of ATC and try to reduce calculation times dramatically. Secondly, we propose a new index for distinguishing critical cases fast using transient energy functions, and a screening method for ranking unstable cases using stepping-out times. We confirm the validity of the proposed approach by running simulations using an IEEJ EAST 10 machine 47 bus system.