Distribution Grid Voltage Control Using Cascaded Multi-level Inverter-based Static Synchronous Compensator

In this article, the voltage control performance of the cascaded multi-level inverter based static synchronous compensator was studied, specifically, a 21-level cascaded multi-level inverter based static synchronous compensator was considered. The switching angles of the cascaded multi-level inverter based static synchronous compensator have been determined by an optimization methodology based on the sequential quadratic programming technique for minimizing the total harmonic distortion of the static synchronous compensator output voltage. To achieve satisfactory performance of the static synchronous compensator voltage controller, two different fuzzy logic control schemes, namely, indirect and direct control systems, have been developed. The performances of these two developed control schemes for controlling the bus voltage were investigated with detailed non-linear fault simulation studies in a practical power distribution system using PSCAD/EMTDC (Manitoba HVDC Research Center, Winnipeg, Manitoba, Canada) software and have been found satisfactory. Furthermore, the performances of the proposed fuzzy controllers have also been found to be superior to that obtained with an indirect proportional-integral controller.