Three-Phase 4-Wire DSTATCOM Based on H-Bridge VSC with a Star/Hexagon Transformer for Power Quality Improvement

In this paper, a H-bridge VSC (voltage source converter) with a star/hexagon transformer as three phase four-wire DSTATCOM (distribution static compensator) is proposed for power quality improvement in three-phase four-wire distribution systems. The proposed DSTATCOM is employed for the compensation of reactive power for the voltage regulation or power factor correction along with elimination of harmonic currents, load balancing and neutral current compensation at the point of common coupling (PCC). The conventional four leg VSC as three-phase four-wire DSTATCOM has eight switches where as there are only four switches in the proposed DSTATCOM. The b-Bridge VSC is able to compensate the power quality problems in the current and the dc bus voltage is regulated to reference value. The winding of star/hexagon transformer provides a path to the zero sequence fundamental as well as harmonics currents. The performance of the proposed DSTATCOM system is validated through simulations using MATLAB software with its Simulink and power system blockset (PSB) toolboxes.