Compensation winding

Compensating winding is an additional winding made up of three strands on a three-phase transformer, which enables symmetrical magnetization of the three legs of the transformer even under unfavorable operating conditions .

In contrast to large transmission transformers, which are usually evenly loaded, smaller distribution transformers can experience asymmetrical or even single-phase loading, for example if the center point is not connected to the neutral conductor in the star connection or it is loaded on one side.

As a result of these so-called unbalanced loads , the current flows back through the less loaded strings on the input side. As a result, the magnetic flux in the associated legs can rise to the saturation range .

This prevents the equalizing winding. The winding of each leg has the same properties (number of turns, wire size, etc.). All three are connected in series and thus short-circuited. If the transformer is unevenly loaded, a compensating current flows, thus avoiding the above-mentioned return flow and undesired saturation can no longer occur. If the load is constant, however, the sum of the voltages is zero, so there is no equalizing current.

literature

• Paul E. Klein: Mains transformers and chokes. 5th revised edition, Franzis Verlag, Munich, 1979, ISBN 3-7723-1065-6
• Günter Springer: Expertise in electrical engineering. 18th edition, Verlag - Europa - Lehrmittel, Wuppertal, 1989, ISBN 3-8085-3018-9

Web links

Operating behavior of three-phase transformers (PDF; 300 kB) at fh-stralsund.de