| 摘要 |
<p>A method for measurement of a.c. power, in particular for transient and subtransient events, in which first input signals which are proportional to instantaneous values of a voltage as well as second input signals which are proportional to instantaneous values of a current are derived and multiplied with each other, and product signals of positive and negative polarity are obtained which are proportional to the product of the current and voltage instantaneous values and thus to the forward power and return power, and in which these product signals are summated by adding the product signals taking into consideration the positive and negative signs in order to determine the effective power, characterised in that for determining the apparent power the product signals proportional to the forward power and the return power are added, wherein the reference line on which the measurement is based is lowered to the lower peaks of the envelope curve of the product signals proportional to the return power.</p> |
