Why reverse power relay is used?

Answer Posted / s.m imran alam

  A reverse power relay using semiconductor components is
provided to sense the phase relationship between current
and voltage in an electric circuit and to trip a circuit
breaker controlling that circuit in the event of reverse
power conditions. The reverse power relay comprises an
amplifier and current multivibrator circuit, an amplifier
and potential multivibrator circuit, a comparator circuit,
and a timing and output circuit. Current and voltage
condition signals from the two multivibrator circuit are
compared in the comparator circuit and, if a reverse power
condition exists, an output signal from the timing and
output circuit operates a trip coil which trips the circuit
breaker. The reverse power relay is powered from the same
power supply as a known type of overcurrent trip device.

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