Cewe Prometer 100 - Page 62

Page 62 of 72
Prometer 100 User Manual
BGX501-943-R01
Active and reactive power
Active and reactive power is calculated as the sum of harmonic component power up to 31st harmonic. The
calculation is made with plus and minus signs, where negative power represents export direction and positive
represents import direction.
P
Total active power
1P
Active power in L1
Q
Total reactive power
1Q
Reactive power in L1
321 PPPP ++=
321 QQQQ ++=
For 2-element meters, two elements are added instead of three.
Apparent power
S
Total apparent power
1S
Apparent power in L1
22
QPS +=
22
111 QPS +=
Energy
Energy is calculated by integrating power (P, Q and S) over time.
Definition of quadrants
The term phase angle is described under its own heading below.
Quadrant I: phase angle 1–90°
Quadrant II: phase angle 90–180°
Quadrant III: phase angle -180–(-90)°
Quadrant IV: phase angle (-90)–0°
Active energy
Active energy is calculated for import and export. The direction is controlled by the sign for active power
(+ import, – export).
Active energy import: quadrant I and IV
Active energy export: quadrant II and III
Reactive energy
Reactive energy is calculated for four quadrants. The quadrant is controlled by the sign for active and reactive
power (e.g., active power >= 0 and reactive power >= 0 corresponding to quadrant I).
Reactive energy import: quadrant I and II
Active energy export: quadrant III and IV
Reactive energy inductive: quadrant I and III