METHOD AND DEVICE FOR MEASURING AN INSULATION RESISTANCE OF A DC VOLTAGE SOURCE CONNECTED TO A SPLIT INTERMEDIATE CIRCUIT IN MAINS PARALLEL OPERATION

To measure an insulation resistance of a DC voltage source connected to a split intermediate circuit, a midpoint potential of the DC voltage source is shifted by different operation of two voltage converters by way of which two poles of the DC voltage source are each connected to one of two parts of the split intermediate circuit. A change in a residual current across all lines that carry a current flowing across the intermediate circuit from the DC voltage source, resulting from the shifting of the midpoint potential of the DC voltage source, is measured.