PROTECTION RELAY WITH POWER TRANSFORMER LATCHING CURRENT OFFSET Russian patent published in 2009 - IPC H02H7/04 

FIELD: electricity.

SUBSTANCE: protection relay consists of a primary current converter implemented as a miniature current transformer or current transformer with gap or transductor with ballast resistance coupled with two-semiperiod rectifier. The current source is generated on the rectifier output and feeds parallel oscillatory circuit at maximum factor of merit, which is defined by the permissible time of protection action. The high-resistant relay driver connected to the time exposition unit is also available in the relay. The integrating resistive-capacitive circuit or electronic integrating unit is connected between common points of inductivity and circuit capacitor and relay driver input. Variable resistance setting the designed factor of merit without circuit inductivity break is connected parallel to the circuit.

EFFECT: increased sensitivity and possible adjustment of dead time.

3 dwg