| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an apparatus and method capable of measuring advance/delay for phases of a current and a voltage of measured power in simple configuration. <P>SOLUTION: The present invention relates to an apparatus which is used together with a digital power-factor indicator for measuring a power factor of measured power from a voltage and a current and discriminates advance/delay for phases of the current and the voltage, including: a means for detecting digital data in a predetermined term for a period of a predetermined length; a first multiplier for sequentially calculating a first product of multiplying new voltage data and former current data at a predetermined time point in a memory sequentially storing data from the detection means; a second multiplier for sequentially calculating a second product of multiplying new current data and former voltage data at a predetermined time point among data in the memory; an arithmetic circuit for integrating and averaging the first product and the second product, respectively, to determine a first arithmetic value and a second arithmetic value; a subtractor for determining a polarity of a difference of the second arithmetic value from the first arithmetic value; and a discriminator for discriminating advance/delay of the phases of the voltage and current from the polarity of the difference. <P>COPYRIGHT: (C)2012,JPO&INPIT |
