Total transfer capability considering FACTS and security constraints

This paper presents a discussion of the effects of flexible ac transmission system (FACTS) devices on total transfer capability (TTC). TTC indicates the power transfer capability among different systems or different subsystems. FACTS devices can redistribute load flow and regulate bus voltages. Development and use of methods for proper implementation of FACTS can help improve TTC to a certain extent. TTC is limited not only by the violation of system thermal and voltage limits, but also restricted by transient stability limits. In this paper, an algorithm to incorporate stability constraints to calculate TTC is proposed. Based on this algorithm, a software package with graphical user interface (GUI) is developed to facilitate comprehensive and flexible analysis of TTC. The WSCC-9 bus system is used as the test system to demonstrate the methodology.