POWER DIRECTION RELAY Russian patent published in 2003 - IPC

FIELD: electrical engineering. SUBSTANCE: power direction relay includes intermediate voltage transformer, intermediate current transformer, double-threshold comparator and actuator connected in series, first and second threshold units with zero threshold level, first and second AND gates, reversible counter which addition input is connected to output of first AND gate, which subtraction input is connected to output of second AND gate and which output is connected to information input of double-threshold comparator, one-shot multivibrator and clock pulse generator connected in series, two series networks, each comprising AND gate, counter and storage register, first pulse former by trailing edge of signals across its input which input is coupled to output " more " of first mentioned threshold unit, second pulse former by trailing edge of signals across its input which input is connected to output " more " of mentioned second threshold unit and first and second OR gates. Relay displays high precision as there is provided adjustment of values of operation thresholds of double-threshold comparator in compliance with present frequency of input signal. EFFECT: increased functional precision of relay. 4 cl, 1 dwg