.Modelica.Electrical.Polyphase.Interfaces.TwoPort .Modelica.Electrical.Polyphase.Interfaces.TwoPortSuperclass of elements which have four electrical plugs. It is assumed that the currents flowing into plug_p1 are identical to the currents flowing out of plug_n1, and that the currents flowing into plug_p2 are identical to the currents flowing out of plug_n2.