| 摘要 |
PURPOSE:To enable the free concentration between a measuring device and a three-phase power line, by comparing voltage and current values to be inputted into a power measuring device to estimate the voltage and current value in the measuring device in the correct connection. CONSTITUTION:Three voltage data at an input section 11 brought in from a voltage input section 11, digitized by an A/D conversion means 13 and stored in an actual input voltage register 14 are discriminated in the phase sequence by a voltage phase sequence discrimination means 16. When normal sequence is judged from the results, the data of the register 14 is stored intact into a correction register 17 while when a sub sequence is judged, it is corrected to opposite porality to be stored. On the other hand, a current value is inputted into a current input section 12 from a current transformer 4 and stored into an actual input current register 15 through a means 13. Then a correction voltage phase is found with a voltage phase discriminating means 20 form data of the register 17 and the register 15 and as a result, a three-phase voltage is calculated with a power calculating means 23 from the correction voltage phase data and an actually input current data. This enables connection between the measuring device and the three-phase power line very easily.
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