It is not possible to change the voltage set point of an external grid during a simulation. The work around is to replace the external grid by an AC voltage source (ElmVac) and then use one of the following approaches:

- define the parameter event for the ElmVac using the available input signal Ul0 [kV] to change the line-line voltage set point.

- it is not possible to change some signals of the voltage source using a simple parameter event, in that case you would have to build a composite model that attaches a simple pass-through model (out = in) to the input of the ElmVac, and then use a parameter event to change it. This applies for signals u0, U_A, U_B, U_C, dphiu, phiu_B, phiu_C inputs of the voltage source.