Analysis of DC Voltage Fluctuation for Series - Connected STATCOM with IGBT Presspack Modules Compensation of Unbalanced Loads

With the series-connected press-pack modules of insulated gate bipolar transistor (IGBT), static synchronous compensator (STATCOM) can be connected to 10-35kV distribution system. For compensation of unbalance loads, the output power and dc voltage of STATCOM would be fluctuated at 100Hz, which affects the operation of STATCOM safely. In this paper, based on the series-connected IGBTs STATCOM (SCI-STATCOM) in positive and negative sequence for unbalanced loads compensating, the simplified dc voltage fluctuation model was discussed, the influence of key components and operating parameters were analyzed, and a delineated method of safe operation area of SCI-STATCOM was proposed. Finally, the simulation results were provided to verify correctness of the proposed delineated method.