DEVICE FOR MEASUREMENT OF GROUNDING PARAMETERS Russian patent published in 1998 - IPC

FIELD: electric power engineering. SUBSTANCE: device has signal former the frequency of which is lower than frequency of first harmonic of supply mains. Device has also frequency-selective measuring circuit with synchronous detector and analog-to-digital converter connected between device potential input and digital indicator. Signal former output is connected to current output of device through current pickup. Reference input of analog-to-digital converter is connected to current pickup output through reference-voltage forming unit. Control input of synchronous detector is connected to current pickup output via phase-shifting circuit. Signal former is provided with synchronous input which is connected to external lead of device, for example to potential input lead. In this case, interference across external lead of device caused by extraneous currents of mains frequency synchronizes signal former. EFFECT: extended dynamic range of output current. 3 cl, 2 dwg