| 摘要 |
PROBLEM TO BE SOLVED: To prevent wrong measurement due to wrong connection and perform repair in its early stages, by judging the connection state of a power supply wire connecting between a three-phase power meter, a current transformer and a voltage transformer. SOLUTION: The line voltages of distribution lines 1-3 are converted into voltage digital values by 1- and 3-side voltage converting circuits 13, 14. Respective 1- and 3-side load currents of the distribution lines 1 and 3 are converted into current digital values by 1- and 3-side current converting circuits 11 and 12. With the voltage and current digital values and power values computed by a multiplication circuit 15 multiplying the line voltages by the load currents, positive- and negative-phase-sequence connection or wrong connection is determined by a CPU 16 and the judged result is displayed by a display circuit 17.
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