Simulation Study of Unified Power Flow Controller

Abstract

The increasing complexity of AC power networks requires a high performance power flow control system in order to obtain a desired power flow and enhance static and dynamic stability. One of the most effective power electronic systems to satisfy these requirements is a UPFC (Unified Power Flow Controller) employing self-commutated converters.
This paper presents basic control strategies and simulation results for the UPFC using EMTP (Electro-Magnetic Transients Program). The simulations were carried out for start and stop operations, power flow change operations in normal system conditions, as well as operations during system fault conditions. Thyristor based bypass switches are used for the protection of the series compensator of the UPFC from system fault currents, and satisfactory protection capability was confirmed.