The normal tap changer model of a transformer can adapt the voltage at the LV- or HV-side. The control is applied when the voltage of a certain terminal is violating the upper or lower voltage limit.

For certain applications, for example when the maximum and minimum voltage limits of a whole supply area of a transformer shall be kept, advanced control strategies can be implemented by using a QDSL (Quasi-Dynamic Simulation Language) model.

In the attached example, a QDSL model for a transformer is implemented, where the voltage of all terminals within a pre-defined feeder is investigated. When the minimum or maximum voltage limit within the feeder is violated, the tap position of the transformer is changed to keep the voltage at all terminals within the defined limits.