Dynamic available transfer capability computation using a hybrid approach

In a restructured electricity market, accurate evaluation of available transfer capability (ATC) with dynamic constraints is a challenging task. An approach to determine dynamic ATC, utilising the benefits of a direct method as well as time-domain simulation method, has been developed. Structure-preserving energy function model, which retains the topology of the network, along with transient stability limit, has been used to compute dynamic ATC for bilateral as well as multilateral transactions in an electricity market. Constant impedance as well as composite models for real power loads have been considered. A new contingency severity index, which takes into account the impact of transactions on the severity of the contingencies, has been proposed to reduce the list of credible contingencies to be considered in determining the ATC. To demonstrate the effectiveness of the proposed method, it has been tested on 10-machine, 39-bus New England system and a practical 60-machine, 246-bus Indian system.