Power flow studies of a large practical power network with embedded FACTS devices using improved optimal multiplier Newton-Raphson method

In this paper, an improved optimal multiplier Newton-Raphson (OMNR) power flow, method is presented for power flow studies of ill-conditioned large power system with embedded Flexible AC Transmission Systems (FACTS) devices. Power injection models (PIMs) of two typical FACTS devices, Phase Shifter (PS) and Unified Power Flow Controller (UPFC), are derived in rectangular form. After detailed analysis, a defect of the original OMNR method is identified and an improved version is presented. Incorporating the derived FACTS power injection models into the improved OMNR power flow program, the impacts of FACTS devices on power system control have been fully tested on the U.K. National Grid Company (NGC) system. The results clearly illustrate the effectiveness of the proposed approach.