LOW VOLTAGE DISTRIBUTION LINE PHASE DETECTING SYSTEM

摘要

PURPOSE:To make possible the accurate phase detection from over the insulation covering with simple constitution by performing the discrimination of earth phase and the discrimination of the advance and lag of the other two phases by way of detecting electrodes. CONSTITUTION:When a detecting electrode P1 is contacted with an earth line W2, there is no output from a circuit 1 which generates square waves corresponding to phase voltage and this is detected in a detecting circuit 5 by the change-over connection of terminals A and D and a transistor 8 does not conduct through a flickering period adjusting circuit 6 and audio frequency oscillating part 7, whereby the discrimination of the earth phase is accomplished. Thence, when the detecting electrodes P1, P2 are contacted with the remaining two wires W1, W2, the square waves corresponding to the respective phase voltages are generated from the circuits 1, 2 and the output of the circuit and the differentiated output of a differentiating circuit 3 corresponding to the output rise from the circuit 2 are subjected to AND treatment in an AND circuit 4. Hence, the output of the circuit 4 becomes high and low levels according to the advance and lag of the phases between the two phases W1 and W2, thus the accurate phase detection from over the insulation covering may be done by the simple constitution.