ELECTROMAGNETIC MEASURING CURRENT RELAY WITH COMPENSATOR Russian patent published in 2009 - IPC H02H3/00 

FIELD: electrical engineering.

SUBSTANCE: relay contains, between a measuring current transformer and its winding, a compensating element, which is in form of two transductors, primary current windings of which are connected to each other in series, while both secondary windings are connected to separate diodes through small current-limiting resistors such that, each diode is in conducting state only in a single direction of primary current. The diodes are earthed through heteropolar electrodes, while other electrodes of diodes through their ballast resistors are connected to the common point of a capacitor and inductor of a parallel oscillatory circuit, the other common point of elements of which is earthed. The inductor used a relay winding, and the circuit is tuned to mains frequency with possibility of setting the Q-factor using a parallel circuit of an active resistor.

EFFECT: more reliable operation.

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