PURPOSE: To detect the grounding accident point in the distribution lines 1a-1 for road illumination laid in parallel along both sides of a road.
CONSTITUTION: The terminals 2 of distribution lines 1a and 1b are connected with each other, and a zero-phase current I0f1 and I0f2 flowing in each distribution line 1a and 1b and the zero-phase voltage V0 on power source side are detected, and the reactance amounts X1 and X2 of vector values V0/I0f1 and V0/I0f2 are sought, and the accident point where the double length 2d of the distribution lines 1a and 1b is divided at the ratio of X1 to X2 is detected as an accident point. It is so arranged that the accident current may turn into the grounding accident point by making parallel two circuits, connecting the terminals of the distribution lines 1a and 1b with each other, whereby the grounding accident occurrence point can be specified automatically based on the current and voltage information at the power source ends of the distribution lines 1a and 1b.
TSURUKAWA SATORU
TSUNODA TAKANORI
