Investigations of an advanced form of series compensation

This paper provides a comprehensive investigation of an advanced form of series compensation. The basic model consists of a series capacitor connected in parallel with a thyristor-controlled reactor (TCR). Proper selection of the thyristor firing angle increases the equivalent series compensation by developing a “loop flow” current through the series capacitor. The mathematical equations describing the voltages and currents through the capacitor, inductor, and thyristors are developed, analyzed, and later verified using the EMTP analysis program. Additionally, a model circuit was constructed to verify the analytical and computer results. The analysis revealed that the ASC circuit approaches its steady state compensation level gradually, approximately 8–10 cycles at higher levels. The analysis also revealed the significant effect of the reactor size on the ASC operating characteristics and on component sizing.