2 comprises three elementary transformers 11 12 and 13 each of which has a voltage transformation ratio of 1 1 a transmitter s which has an output voltage of for example 3 2u 500 v is connected to the input terminals 6 and 7 of the primary winding of the line transformer 2 a load l is connected to the output terminals 8 and 9 the input terminal 7 and the output terminal 9 are connected to ground the primary windings of the elementary transformers 11 and 12 are connected in parallel and this combination is connected in series with the primary winding of the elementary transformer 13 as shown the primary windings of the elementary transformers 11 and 12 thus transmit the voltage u 2 and the primary winding of the transformer 13 transmits the voltage u the secondary windings of the transformers 11 and 12 are connected in series and this series combination is connected in parallel with the secondary winding of the transformer 13 on the secondary side thus the transformers 11 and 12 each transmit voltages of u 2 and the transformer 13 transmits the voltage u so that the overall voltage at the secondary side is u the cable impedance z 0 of the three elementary transformers 11 12 and 13 is respectively selected so that the impedance of the primary side is z which is approximately equal to 3 2 z 0 and the impedance of the secondary side is z 2 u2248 2 3 z 0 fig2 illustrates a practical embodiment of the.