Multi-step static VAr compensators analysis

Since the concept of FACTS was introduced, a new family of power electronic equipment has emerged for controlling and optimizing the performance of power systems, e.g. STATCOM, SSSC and UPFC. The use of voltage-source inverter (VSI) has been widely accepted as the next generation of reactive power controllers to replace the conventional VAr compensation. This paper aims to present the analysis of operating characteristics of the static synchronous compensator (STATCOM) based on multi-step voltage-source inverters. A detailed analysis of both six-pulse and twelve-pulse is presented and the equations that describe the performance of each circuit are derived. Finally a comparison between digital simulations using the PSCAD/EMTDC and analytical results is shown.