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From the Metering Menu, select Metered Data and select the
first choice, V,A,PF, and Freq.
The following screen appears:
On this screen, the current for each phase is shown in Amps.
The voltage between any two lines and from each line to
ground is shown in Volts. Also shown are the per phase power
factors and whether each is leading (LD) or lagging (LG). The
frequency is a calculated value in Hertz and may differ slightly
from the system frequency. In the example above, the fre-
quency was calculated to 60.0 Hz.
The SB Energy-Comm trip unit calculates the averages of the
metered parameters every second and calculates the Watt,
VAR, and VA values. The frequency calculation task is per-
formed once per second.
The conventions for power flow and power polarity are shown
in Figure 8.1 and Figure 8.2, respectively.
Export
Reverse
Negative
(kW/kVAR supplied
by the load)
Import
Forward
Positive
(kW/kVAR consumed
by the load)
Figure 8.1 Power Flow Conventions
V Source
Load
+kVAR (Reactive Power)
-kW (Reverse)
+kVAR (Forward)
-PF (Leading)
II
Ø=180º
III
PF=-1
-kW (Reverse)
-kVAR (Reverse)
+PF (Lagging)
Figure 8.2 Power Polarity Conventions
To view the calculated values, select Metering Data from the
Metering Menu and then select the second choice, W, VAR,
VA, and CF.
The following display appears:
The forward real power (kW), reactive power (kVAR), and
apparent power (kVA) are shown first, followed by the real
energy (kWhr) values. Finally the crest factor is shown for each
phase (A, B, and C).
Metering
Ø=90º
+kW (Forward)
PF=0
+kVAR (Forward)
+PF (Lagging)
Ø
I
+kW (Real Power)
Ø=0º
IV
PF=1
+kW (Forward)
-kVAR (Reverse)
Ø=270º
-PF (Leading)
PF=0
41
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