Power Flow-Improvement in Transmission System by Using Hysteresis Current Control 84 Pulse Statcom

The Static Synchronous Compensator (StatCom) is one of the most useful FACTS devices, since it can synthesize the reactive power from small storing elements. When it is operated within the linear region, it is seen by the system as a synchronous voltage source. By regulation of the Statcom‟s output voltage magnitude, the reactive power Exchange between the device and the transmission system may be controlled to improve the power system voltage profile. This paper describes a strategy to generate the 84-pulse VSC, assembled with the combination of one 12-pulse converter with a sevenlevel converter, as well as one reinjection transformer to attain the required performance. The extra components are: 8 switches, 4 DC voltage sources, and 4 diodes for the seven-level converter. A reinjection transformer is needed which is able to work properly within a wide range of its turn ratio. This constitutes an attractive array in terms of costs. Since stat com is a shunt device, hysteresis current control is choosen as a best pulses generator, and the simulation is done in Matlab software.