Modeling and State Feedback Controller of SSSC Based Current Source Converter

Static synchronous series compensator (SSSC) is a series connected FACTS devices. It is able to providing the reactive power compensation of power system. The SSSC injects a series ac voltage to transmission line through a transformer, which leads or lags the line current by 90°, thus emulating a controllable inductive or capacitive reactance. SSSC can be used to reduce the equivalent line impedance and thus enhance the active power transfer capability of the transmission line. SSSC is conventionally realized with a voltage-source converter. In this paper, an SSSC based on the current-source converter topology is proposed. The injected voltage is controlled according to the desired reactive power compensation. The decoupled state-feedback control for the injected voltage with a separated dc current control is applied to the proposed system. The advantages of the proposed scheme include fast dynamic response and high quality of current and voltage waveforms. The proposed SSSC has been simulated using the MATLAB software. The simulation results show that excellent current and voltage waveforms as well as very short response times can be obtained while operating at a low switching frequency. This makes the proposed scheme suitable for high power applications.