A 3×6 pulse NPC-VSC based 100 MVAr STATCOM modeling and applications

In a combination of multi-pulse and multi-level voltage source converter (VSC) topology employed in high power rating Static Synchronous Compensator (STATCOM), when the pulse-order is increased, there is a corresponding increase in the requirement of converter units and magnetics, which increases the complexity of controllability and cost. This paper is aimed to achieve a lower-pulse order high power rating STATCOM enabling to obtain a reasonably acceptable harmonics and operational performance at optimum cost. A three-level 18-pulse STATCOM employing three numbers 6-pulse neutral point diode clamped (NPC) GTO-VSCs operated under fundamental frequency switching (FFS) modulation, in combination with typical magnetics architecture and angle control is modeled and simulated in MATLAB platform demonstrating performance equivalent to a 36-pulse STATCOM for power system applications. The simulation results for voltage control and unity power factor correction in a transmission system during steady state and dynamic system conditions are well supporting to validate the model.