To obtain an apparatus for detecting the individual operation of a dispersed power supply, precisely irrespective of whether the overall length of a distribution line is long or short.
This detecting apparatus for an individual operation is provided with a current injection device 32 and a supply-stop detecting device 42. By the current injection device 32, a harmonic current Im which is synchronized with the fundamental- wave voltage of a distribution system and whose intermediate order is at a nonintegral multiple of less than 2.7 times the funamental-wave voltage is injected into a lead-in wire 18 in a customer installation 14 provided with a dispersed power supply 30. The supply-stop detecting device 42 is provided with an admittance computing circuit an a judgment circuit. The admittance computing circuit computes an admittance at the intermediate order of the distribution system as viewed from a receiving point A, and it calculates a conductance and a susceptance. The judgment circuit outputs a supply-stop detection signal S when the susceptance is changed by a prescribed value or higher in a capacitive direction, and it outputs the supply-stop detection signal S when the conductance is changed by a prescribed value or higher in the positive direction even in a case other than it.
NISHIMURA SOJI
MINOWA YOSHIBUMI
NISSIN ELECTRIC CO LTD
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