Charging techniques for energy-storage capacitors of static series compensator

The injecting capability of the static series compensator (SSC) to mitigate voltage dips is limited by its energy storage size. Among the existing energy storage devices, capacitors are considered the most feasible solution for high power applications. This paper proposes and describes two control techniques to charge such capacitors. One technique uses a shunt diode rectifier, which is placed either on the load side or the grid side (both configurations are studied). The other technique exploits the voltage source converter of the SSC with a proper control algorithm. A design guide for the energy storage capacitor is given. The proposed techniques are validated by PSCAD/EMTDC simulation.