Energy Calculations; Measurement Formulas - AEMC PEL 102 User Manual

A.1.2.8 Energy Calculations
Energies are calculated every second.
The "Total" energy is the demand during the recording session.
The "Partial" energy can be determined during an integration period with the following values: 1 h, 1 day, 1 week, 1 month.
The partial energy index is available only in real-time. It is not recorded.
However, the "Total" energy is available with the recording session data.
A.2 Measurement Formulas
PEL measures 128 samples per cycle (except 400 Hz with 16 samples) and calculates the voltage, current and active
power quantities on a cycle.
PEL instruments measure or calculate the following quantities on a cycle (128 samples per cycle, except 400Hz with 16
samples). Then the PEL calculates an aggregated value for 10 cycles (50Hz), 12 cycles (60Hz) or 80 cycles (400Hz).
The 10/12 cycles quantities (50Hz) are aggregated for 50/60 cycles ("1 second" quantities).
Quantities
AC RMS Line-to-neutral
voltage (V )
L
DC voltage (V )
L
AC RMS Line-to-line
voltage (U )
L
AC RMS Current (I
DC Current (I )
L
Voltage crest factor (V-CF)
Current crest factor (I-CF)
Unbalance (u )
2
(real-time only)
Active Power (P )
L
Reactive Power (Q
Apparent Power (S
Power Factor (PF
88
)
L
with
)
L
)
L
)
L
Formula
Power & Energy Logger Model PEL 102 and PEL 103
Comments
vL = v1, v2 or v3 elementary sample
N = Number of samples
L = v1, v2 or v3 elementary sample
N = Number of samples
ab = u , u or u elementary sample
12 23 31
N = Number of samples
iL = i1, i2 or i3 elementary sample
N = Number of samples
iL = i1, i2 or i3 elementary sample
N = Number of samples
CF is the ratio of average crest values and rms
VL
value of 10/12 periods
CF is the ratio of average crest values and rms
IL
value of 10/12 periods
L = I1, I2 or I3 elementary sample
N = Number of samples P [1s]= P
T
+ P [1s]
3
Reactive power includes harmonics.
"sign[1s]" is the reactive power sign
Total reactive power calculation Q
Total apparent power S [1s] is an arithmetic
T
value
[1s] + P [1s]
1 2
[1s] is vector.
T