In the electric system, distribution transformers are used for the final transformation of voltage to the level required by the final user. Powers of such transformers are usually between 50 and 1600 kVA, while voltage ratio in modern systems is 20/0.4 kV. It is typical of these transformers to have a switch integrated that allows changing of voltage ratio between the primary and the secondary side of transformer in de-energized state, but only to some extent (+- 2 x 2.5%). Furthermore, these transformers cannot adapt to the current voltage conditions in the grid, which results in a certain level of voltage oscillation for the user. This problem is solved with a regulating transformer that contributes to better quality of electrical energy for the final user.
The trend in development is application of smaller regulating switches with dimensions adjusted to the dimensions of transformers. Moreover, they enable more levels with integration of an additional adjustable autotransformer in each phase of the existing transformer, but that requires different type of transformer windings. A long lasting cooperation with the Maschinenfabrik Reihhausen company enabled a step further in the direction of production of regulating distribution transformers to Kolektor Etra, the Kolektor subsidiary.
As the result of common expert knowledge, a prototype of distribution transformer for the application in smart grids was developed. For optimal operation of the system, exact analysis of operation of power grids as the basis for defining the location of regulating transformer application is required.