Control of static series compensator for mitigating grid voltage disturbance and load current harmonics

This paper proposes a coordinated control method, for static series compensator (SSC) equipped with shunt passive filters, to compensate grid voltage disturbance (sag, swell, voltage interruption and flicker) and load current harmonics. To effectively extract the positive-sequence component of the grid voltage, digital all-pass filters are implemented. These filters can deliver a preferred phase shift and no magnitude drop, unlike conventional low or high-pass filters. According to the extracted positive-sequence component, the angle of the grid phase and the reference voltage for compensation are obtained. This technique can improve the grid voltage stability and mitigate the load current harmonics as well. PSCAD/EMTDC simulations show the usefulness of the proposed technique.