The Unified Power Plow Controller (UPFC) is a flexible AC Transmission Syst
em (FACTS) device capable of controlling line flows and terminal voltage. I
n order to analyze its true effects on power systems, it is important to mo
del its constraints due to various ratings and operating limits.
Innovative techniques are introduced in this paper for fast power flow conv
ergence with various UPFC control modes and simultaneous multiple limits en
forcement, while the line side bus remains explicitly accessible. An effici
ent algorithm is developed for applying the line side voltage limits, which
avoids the possible hunting between shunt and series converters of UPFC.
Control models with similar constraints are also developed for stability st
udies. Simulations are performed using EPRI's Power Ssystem Analysis Packag