H-Bridge Multi Level STATCOM under Different Loads

Voltage control and fast reactive power compensation are two main application area of Static Synchronous Compensator (STATCOM), which is a shunt connected voltage source converter (VSC) based FACTs controller using power semiconductor devices (particularly IGBT, GTO etc.).However, the total Statcom circuitry has complex and coupled system dynamics which require advanced controllers to achieve well performance. In our paper, we have represented a sixty pulse VSC for producing higher pulse number by combining a twelve pulse converter with a five level VSI in order to obtain the overall performance of the said VSC in a three phase system. As the number of levels increases in the VSI of the Statcom, it will produce a staircase wave with lower value of THD. The simulation results are presented and it is observed that the STATCOM shows excellent response to step change in the reactive current reference & the value of THD is also within the acceptable limit. A new efficient control strategy is proposed, in order to reduce the voltage fluctuations like sag and swell conditions and also to isolate current and voltage harmonics in the transmission system. The multilevel STATCOM which can be used at the point of common coupling (PCC).The static synchronous compensator (STATCOM) is used in power system network for improving the voltage of a particular bus and compensate the reactive power. It can be connected to particular bus as compensating device to improve the voltage profile and reactive power compensation.