Three-Level 12-Pulse STATCOM with Constant DC Link Voltage

In this paper, an operation methodology of a STATCOM (static synchronous compensator) is proposed with constant dc link voltage. For achieving this objective, two sets of three-level 12-pulse VSCs are used which are operated at the fundamental frequency switching. The reactive power is controlled by the phase angle difference between the two sets of three-level 12-pulse VSCs. Detailed analysis is made to find out the optimum value of conduction angle to get minimum THD (total harmonic distortion). The converter utilization in the proposed configuration of STATCOM is improved as it is working at a constant dc link voltage. The proposed model of the STATCOM is connected to a 33 kV, 50 Hz system and simulation results are presented for demonstrating its steady state and dynamic performance.