Simulation of three-level 24-pulse voltage source converters-based static synchronous compensator for reactive power control

The proposed STATCOM (static synchronous compensator) consists of two sets of three-level 24-pulse VSC (voltage source converter) gated at the fundamental frequency. The dc-link voltage of VSC is maintained at a constant value unlike the common operation of the STATCOM with a variable dc-link voltage. The phase angle between the ac voltages produced by two sets of three-level 24-pulse VSCs is varied for controlling the magnitude of the converter ac voltage which in turn controls the reactive power of the STATCOM. The proposed STATCOM has the advantage of maximum utilisation of the converter as it is operated at a constant dc-link voltage. The dynamic and steady-state performances of STATCOM are evaluated by varying the reference reactive power, the reference terminal voltage and switching on inductive and capacitive loads.