| 摘要 |
TITLE INSTRUMENT TO MEASURE THE ERRORS OF APPARENT POWER METERS INVENTORS Réjean J. Arseneau Piotr S. Filipski John J. Zelle An instrument to determine, under actual field conditions, which type of VA demand meters are most appropriate for a particular consumer. The type of electrical load that the consumer places on an electrical supply system can introduce harmonics and phase distortion in the system resulting in VA meters producing incorrect readings. These VA meters are intended to measure the true apparent power S which is defined as S = Vrms X Irms but, are generally designed to operate according to one of the following approximate formula: (1) S' = Vrect X Irect X (1.11)2 and (2) S" = where P is the active power and Q the reactive power. The instrument contains a circuit to measure the rms values of the voltage and current waveforms from which the true apparent power S can be obtained as well as circuits to determine the value S' and S" according (Cont.) to the two approximate formula from which error signals e1 and e2 can be determined to indicate the type of errors that can be expected from VA meters designed to operate according to the two approximate formula and, as a result, determine which type of VA meter is most appropriate for a particular consumer. |
