Due to the parallel course of three-phase circuits and other infrastructures, such as railway circuits, gas pipelines and communication lines, undesirable electromagnetic interference can occur. Particularly in current discussions about increasing the operating currents in normal operation by using high-temperature conductor cables or overhead line monitoring, new questions arise for existing lines with regard to compliance with permissible limit values in terms of electromagnetic interference. The IAEW has a procedure with which a quasi-stationary interference investigation can be carried out on the basis of the operating currents and voltages in normal operation or in the event of a fault to check compliance with permissible limit values. The basis of the procedure is the mapping of the capacitive and inductive influence via coupling capacitances or inductors. These are determined on the basis of the geometric arrangement of the various conductors and the electrical and magnetic properties of the three material areas conductor, air and ground.