Control algorithm for a SSSC

The power grid in most of the countries is aging and under increasing stress. The modern industrial infrastructure demands increasing amounts of affordable and reliable electricity. Solutions based on flexible AC transmission systems (FACTS) can be used to control power flow on the grid. Shunt VARs compensators provide grid voltage support, while series VARs compensators are required to control active power flow. The synchronous static series compensator (SSSC) controls the active power flow by altering the impedance of the power lines or changing the angle of the voltage applied across the line. This paper presents a control algorithm for a SSSC which injects a voltage in series with the line in order to control the power flow. The amplitude and angle of the injected voltage is calculated as a function of the compensation rate and in order to control the DC bus voltage of the converter. A predictive synchronization algorithm is used to obtain the phase of the line current.