| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve a problem wherein if branch paths L5 branched from feed paths L1, L2 and a voltage detection circuit 14 for detecting a contact welding in a relay 10 from a current flowing in the branch paths L5 are provided, the magnitude of a current I1 flowing in the feed paths L1, L2 from a power supply to an electric vehicle B and the magnitude of a current I2 flowing back in the feed paths L1, L2 from the electric vehicle B to the power supply are always different by the magnitude of a current I3 in the branch paths L5, thereby causing a zero-phase-sequence current transformer ZCT to wrongly detect the difference in current as a leakage. <P>SOLUTION: The branch paths L5 are made to pass through the zero-phase-sequence current transformer ZCT in a direction in which the current I3 flows in the same direction as a direction of the current I2 flowing back in the feed path L1 or L2 from the electric vehicle B to the power supply. Consequently, the zero-phase-sequence current transformer ZCT detects an unbalance of a combined current of the currents in the feed paths L1, L2 and the branch paths L5, and thereby can correctly detect a leakage. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
