MI 2792A PowerQ4 Plus Ang Ver 1.0 20 752 082

MI 2792A PowerQ4 Plus

Total power factor (vector):

PFtot



Pt

St

.

Theory and internal operation

(16)

Figure 5.2: Vector representation of total power calculus

5.1.7 Energy

Standard compliance: IEC 61557-12 (Annex A)

Energy counters are linked to RECORDER functionality. Energy counters measure energy only when RECORDER is active. After power off/on procedure and before start of recording, all counters are cleared.

Instrument use 4-quadrant measurement technique which use two active energy counters (eP

+

, eP

-

) and two reactive (eQ

+

, eQ

-

), as shown on bellow.

Le ad

Le ad

La g

La g

Figure 5.3: Energy counters and quadrant relationship

Instrument has 3 different counters sets:

1. Total counters TOT EN are intended for measuring energy over a complete recording. When recorder starts it sums the energy to existent state of the counters.

2. Last integration period LST.IP

counter measures energy during recording over last interval. It is calculated at end of each interval.

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