Fault current limiting and power system stabilization by static synchronous series compensator

In this paper, a control scheme of the static synchronous series compensator (SSSC) for fault current limiting and power system stabilization has been proposed. The apparatus injects a voltage of variable magnitude in series with a transmission line. This injected voltage is in quadrature with the line current. Under normal condition, it is controlled in order to compensate for reactance of the transmission line. When a disturbance occurs, injected voltage from the phase shifter is applied to damping control of generator swing. As a result, the proposed controller is expected to improve steady-state stability. This apparatus is also expected to be a promising fault current limiter by using the leakage reactance of a series transformer. The effectiveness of the proposed controller is evaluated from the viewpoints of current limiting and steady-state stability improvement based on numerical analyses.