Two-level multi-area TTC calculation by updating power transfer distribution factors

This paper presents a method of calculating the total transfer capability (TTC) in a multi-area power system, where control areas do not share their network data amongst them. A quadratic approximation is developed for the nonlinear power transfer distribution factors (PTDFs) by using the Taylor series expansion. This approximation is used to update PTDFs, which are then used to calculate nonlinear TTC in each control, area while a central entity coordinates these results to determine the final system-wide TTC value. The developed procedure is successfully applied to calculate the TTC for the IEEE 118 bus test system. Comparative numerical results obtained by using the integrated and the multi-area procedure are presented to validate the proposed method.