Compensated Watts And Vars (Line And Transformer Loss Compensation) - Novatech Bitronics M660 User Manual

6.7 Compensated Watts and VARs (Line and Transformer Loss Compensation)

The total Watt and Var losses can be calculated using five user entered parameters
and measured current and voltage values. These losses are added or subtracted
to/from the measured Total Watts and Total Vars when accumulating Energy.
Loss compensation on the M66X takes the following general form:
Where:
P
Compensated three-phase total watts. Note the accumulators for +kWh and –
COM
kWh in the M66X are calculated by integrating the P
P
Uncompensated three-phase total watts measured at the point where the meter
UNC
is connected.
Q
Compensated three-phase total VARs. Note the accumulators for +kVARh and –
COM
kVARh in the M66X are calculated by integrating the Q
time.
Q
Uncompensated three-phase total VARs measured at the point where the meter
UNC
is connected.
I
RMS line current measured at the point where the meter is connected.
V
RMS line-line voltage measured at the point where the meter is connected.
Meter setting that accounts for the sum of the full-load-watt-losses from all
A
sources.
Meter setting that accounts for the transformer's no-load-watt-losses.
B
Meter setting that accounts for the sum of the full-load-VAR-losses from all
C
sources.
Meter setting that accounts for the transformer's no-load-VAR-losses.
D
Meter setting that accounts for any "system" losses, proportional to the
E
uncompensated power.
Configuring the meter to perform loss compensation simply requires the user to
calculate the coefficients A, B, C, D, and E defined above, and enter them in the
appropriate fields in the M66X's webserver interface on the Settings/Input page as
shown in the screen shot below
The sign of the settings A, B, C, D, and E determines whether losses will be added to
or subtracted from the uncompensated measurements in order to determine the
compensated power and energy. To add losses, be sure the settings are all positive.
To subtract losses, be sure the settings are all negative. Settings should always have
the same sign.
Making all of the settings equal to zero turns off loss compensation.
System losses (E) are a fixed percentage, mutually agreed upon between two electric
utilities, about an interchange point that lies on a branched line. As such, E is not a
physical property of any particular line, transformer or the meter, so no further
ML0042 October 15, 2019
P = P
2
+ A·I + B·V
COM UNC
Q = Q
2
+ C·I + D·V
COM UNC
- 95 -
2
+ E·P
UNC
4
+ E·Q
UNC
measurement over time.
COM
measurement over
COM
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