Three-Phase Four-Wire DSTATCOM with Reduced Switches for Power Quality Improvement

Asian Power Electronics Journal 2.


In this paper, a two-leg VSC (voltage source converter) integrated with a star/hexagon transformer is used for the power quality improvement in three-phase four-wire distribution system. The primary winding of the transformer is star connected and it provides a path to the zero sequence fundamental as well as harmonics neutral currents. The secondary windings of the transformer are connected in hexagon manner and it provides isolation to the two-leg VSC. In order to optimise the voltage rating of the two-leg VSC, the secondary winding of the transformer is suitably designed. The proposed DSTATCOM (Distribution Static Compensator) provides the voltage regulation or power factor correction by reactive power compensation, harmonics elimination, load balancing and neutral current compensation in three-phase four-wire distribution system. This topology has the advantages of the use of 'off the shelf' two-leg VSC, reduced size and cost. The rating of the transformer remains same when it is compensating the neutral current due to unabalance in the load. The performance of the proposed DSTATCOM system is validated through simulations using MATLAB software with its Simulink and Power System Blockset (PSB) toolboxes.

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