measuring method for measuring the schleifenwiderstandes of electricity with nulleitern

摘要

Means for measuring resistance of a power supply loop comprising a three phase, neutral pus earth cable but which also has a device for protection against power faults. The procedure comprises supply of as large a current as possible between one of the three phase conductors (L1-L3) and neutral (N) and measurement of voltage change between earth (PE) and the phase conductor with the extra supplied current and network current present. The procedure is repeated but with the current between one of the phase conductors (L1-L3) and earth (PE), so that the protection device (SS) is not triggered, while the change of voltage between neutral (N) and earth (PE) is measured with extra supplied and network current present. The loop resistance is calculated from the sums of the resistances measured from the voltage changes measured by supply of the extra current.