Enhancement of first-swing stability using a high-speed phase shifter

The static phase shifting transformer (SPST) is one of the potential options of the recently presented concept of flexible AC transmission systems (FACTS). An application of the SPST is presented for solving the transient stability problem of a generator connected to a power system. The control algorithm of the SPST is conceptualized to prevent loss of synchronism by extending the capability of a generator to produce sufficient decelerating energy to counterbalance the accelerating energy gained during a fault. The results of simulation studies confirm the validity of the theory on which the control algorithm is based. Phase shifting control not only prevents loss of synchronism but also damps the subsequent swings.>