Attached, you can find three examples showing different approaches to implement a tap changer and shunt control.

1. Direct control via signal:
   The project "SIM TapControl nntapin.pfd" shows a tap controller directly accessing the tap position controller signal nntapin.
2. Control via tap events:
   The project "SIM TapControl event.pfd" uses DSL parameter events to change the tap position. In the model, the transformer LV terminal voltage is monitored; if the controlled voltage is higher than umax and exceeds Tdelay seconds, then the associated transformer's tap position is increased. If the controlled voltage is lower than umin for more than Tdelay seconds, then the associated transformer's tap position is decreased.
   Both approaches, via signal and using events, are equivalent. The user can select the method that best suits their needs. The same frame could be used for more sophisticated controllers.
3. The third project, "SIM SwitchedControllers.pfd," also includes an event-based controller for three applications: a 2-winding transformer, a 3-winding transformer, and a shunt element.
   The tap/step positions can be set either manually or via an external file; this is controlled by the parameter “ManualMode” in the ShntController.ElmDsl. The external file (TapSet.txt) should be stored in the C:\Temp folder, or the user must relocate it to the "TapSettings" object within the project.