An external grid can have different phase impedances modelled by using a line element defined by a tower type. The tower type is configured such that the user can enter the 3x3 impedance matrix. The conductor type is used to set the rated voltage and current of the line. The GMR, DC-Resistance parameter is not used if the input mode is set to electrical parameter. In the load flow page of the tower type object, the user can set the impedance matrices. An example is attached to demonstrate this application.