Patent ID: 8749246

Claim:
A method for determining a maximum leakage current in unearthed power supply networks with a plurality of live conductors, wherein the method comprises the steps of: (a) feeding a measurement signal U P with a measurement frequency f Puls into a conductor arrangement formed in the unearthed power supply networks; (b) setting the measurement frequency f Puls ; (c) measuring a line-to-line voltage U L-E for each conductor of the plurality of live conductors; (d) determining a maximum occurring line-to-line voltage U L-Emax from the plurality of measured line-to-line voltages U L-E obtained by measurement in step (c); (e) determining a voltage U Ze across a measurement resistance R M taking into account the measured line-to-line voltages U L-E for each conductor of the plurality of live conductors; (f) calculating a leakage impedance Z E using the voltage U Ze determined in step (e) across the measurement resistance R M ; (g) calculating a maximum leakage current THC using the calculated leakage impedance Z E and using the maximum occurring line-to-line voltage U L-Emax ; and (h) repeating the previous steps (a) thru (g), wherein the measurement frequency f Puls is changeable during the measurement of step (c), and the setting of the measurement frequency f Puls in step (b) takes place automatically by means of an interference frequency analysis.