For regulating transformers, there are a variety of types and designs. These have the advantage that they can work directly from the medium-voltage system on the electrode voltage.
Essentially, two types of control are distinguished: Firstly, the control of the induction. Here the voltage is changed by phase lead. And on the other hand, the direct voltage regulation by contact tap on the secondary side. This system is used in each case as a single-phase and three-phase system.