The variations of the stator voltage are reflected in the active and reactive power consumed by the alpha-beta load, which are proportional to the voltage at the load terminal.
Initial equations are provided on the generator differential variables to ensure a steady state initialization by OpenModelica. It had to be written here and not directly in Dynawo.Electrical.Machines.OmegaRef.GeneratorSynchronous because the Dynawo simulator applies a different initialization strategy that does not involve the initial equation section.