SSSC - Static synchronous series compensator: Theory, modeling, and applications

This paper describes the theory and the modeling technique of a Flexible Alternating Current Transmission Systems (FACTS) device, namely, Static Synchronous Series Compensator (SSSC) using an Electromagnetic Transient Program (EMTP) simulation package. The SSSC, a solid-state voltage source inverter coupled with a transformer, is connected in series with a transmission line. An SSSC injects an almost sinusoidal voltage, of variable magnitude, in series with a transmission line. This injected voltage is almost in quadrature with the Line current, thereby emulating an inductive or a capacitive reactance in series with the transmission line. This emulated variable reactance, inserted by the injected voltage source, influences the electric power now in the transmission line.