Directional relay for AC networks with two supplies - has differential quotient of clipped AC current triggering indicating relays

摘要

The directional relay, for a.c. networks with two supplies, has the a.c. voltage and current and the 180 deg. phase-shifted a.c. current clipped by zener diode circuits into trapezium-shaped current waveforms. The positive differential quotient of the trapezium current waveform during the positive half wave triggers the direction indicating relays. The advantage of the circuit is its direct processing of the a.c. voltage and a.c. current which allows the whole directional relay circuit to be manufactured more economically than existing types because the number of electronic components is less.