| 摘要 |
PURPOSE:To provide a highly durable and accurate reactive power meter which is designed to meter the amount of reactive power by means of a purely digital metering system. CONSTITUTION:The voltage and current of a power system to be measured are detected by a voltmeter 1 and an ammeter 2 respectively and given to A-D converters 3, 4 and also the output of the voltmeter 1 is given to a phase synchronizing pulse generator 5. Upon receipt of each pulse from the pulse generator 5, A-D converters 3, 4 convert input signals into sample values, and the output of a shift register 6 to which the output of the A-D converter 3 is given becomes a sample value of which phase is delayed by 90 deg. from that of the voltage of the voltmeter 1. The output of the shift register 6 is multiplied by the output of the A-D converter 4 by a multiplier 7 and the result is integrated by an adder 8 and the amount of reactive power is displayed on a digital display unit 9. By this method, the amount of reactive power can be obtained at a high accuracy. |
