Transformers TMG 21 are three-phase oil transformers. Transformers are manufactured with a combination of 6 / 0.4 kV, 6.3 / 0.4 kV, 10 / 0.4 kV, 10.5 / 0.4 kV, 35 / 0.4 voltages with diagrams and winding connection groups D / Yn-11 and Y / Yn-0.

The low voltage winding of transformers of this series is made not of aluminum wires, but of aluminum foil, which combines ease of winding with a high level of reliability.
The width of aluminum tape is equal to the height of the low voltage winding – this significantly reduces the axial dynamic forces in transformer.

DDP paper was used as an interlayer insulation, which is sintered during the drying process of the windings. In this way, a dense, holistic design is created, with increased resistance to radial forces.