SSSC-static synchronous series compensator: theory, modeling, and application

This paper describes the theory and the modeling technique of a Flexilile Alternating Current Transmission Systems (FACTS) device, namely, Static Synchronous Series Compensator (SSSC) using an Electromagnetic Transient Program (EMTP) simullation package. The SSSC, a solid-state voltage source inverter coupled with a transformer, is connected in series with a transmission Line. A0 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 flow in the transmissioni line.