THREE-PHASE TRANSFORMER UNIT Russian patent published in 2007 - IPC H01F30/12 H01F30/02 H01F29/02 

FIELD: electrical engineering; transformer units for feeding rectifiers of high-power converter substation in aluminum industry.

SUBSTANCE: proposed three-phase transformer unit has main three-phase group of primary bushings and at least two active parts of which first one is made in the form of autotransformer incorporating at least first winding and second winding. Starting lead of each second-winding phase is connected to respective bushing of main three-phase group of primary bushings. Second active part is made in the form of transformer that has primary, secondary, and phase-shifting windings. The latter is connected to transformer primary winding so that its first-phase coil is connected in series with third-phase coil of transformer primary winding. Its second-phase coil is connected in series with first-phase coil of mentioned winding. Its third-phase coil is connected in series with second-phase coil of mentioned winding. Starting lead of first-phase coil of first winding is connected to starting lead of second-phase coil of second winding. Finishing lead of second-phase coil of second winding is connected to finishing lead of third-phase coil of first winding. Finishing lead of first-phase coil of first winding is connected to finishing lead of third-phase coil of second winding. Voltages applied to phase coils of primary winding are shifted in phase relative to respective supply-mains voltages.

EFFECT: simplified design and circuit arrangement of windings, reduced size and mass, enhanced throughput capacity.

6 cl, 2 dwg