PlusTM and
PM™
Units
3.
Mode
Total Apparent Power
The value displayed for total apparent power, as
illustrated in Figure
53,
represents the aggregate
total apparent power in volt-amperes flowing
through all three phases. The value is displayed from
0 to 999 kVA, then automatically switches units to
display 1 .00 to 999
MV
A.
METER
' , ,
�
'·-· '
MVA
Figure
53.
Trip Unit display for aggregate apparent power.
Power Demand
Power demand is the average of total power over the
selected interval
(5,
10,
. . . , 55,
60 minutes) . This dis
play is updated every minute. The power demand
display is illustrated in Figure 54.
' , .�
..
-
f.L _I
MN METER
DEMAND
Figure
54.
Trip Unit display for power demand.
Peak Power Demand
Peak power demand is stored in nonvolatile mem
ory. Every minute, the power demand is calculated
and compared against the stored peak power
demand. If the new power demand is greater than
the stored peak demand, the Trip Unit stores the
new power demand as the peak value. The display of
peak power demand is identical to the display illus
trated in Figure 54, except that the units segment (in
this case,
MW)
flashes.
Peak demand is stored in nonvolatile memory. The
value in the display can be reset through the Trip
Unit keypad. To reset the peak demand to the pres-
29
ent demand, hold down the
VALU E
key and press the
SELECT
key.
Frequency
This display, illustrated in Figure
55,
shows the fre
quency of the line current. Either line voltage or
current must be present for this display to appear.
The frequency is calculated from the current and
voltage signals. If both are present, the voltage fre
quency is displayed. If neither are present, this dis
play does not appear.
The frequency is displayed in steps of 1 Hz .
.
�
.,
0
,_,
\31
Hz
METER
Figure
55.
Trip Unit display for frequency.
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