Power Meter Bulletin No. 3020IM9503R6/98
Chapter 8—Metering Capabilities December 1998
58 1998 Square D All Rights Reserved
• kVA Phase A, Phase B, Phase C, 3-Phase Total
• THD/thd Current Phase A, Phase B, Phase C
• THD/thd Voltage Phase A, Phase B, Phase C
You can view these values using the power meter display, and reset them
using the Reset mode (see Performing Resets in Chapter 7).
Using POWERLOGIC application software you can:
• view all min/max values
• upload min/max values from the power meter and save them to disk
• reset min/max values
For instructions on viewing, saving, and resetting min/max data using
POWERLOGIC software, refer to the instruction bulletin included with the
software.
POWER FACTOR MIN/MAX CONVENTIONS
All running min/max values, with the exception of power factor, are arith-
metic minimums and maximums. For example, the minimum phase A–B
voltage is simply the lowest value in the range 0 to 3,276,700 V that has
occurred since the min/max values were last reset. In contrast, power factor
min/max values—since the meter’s midpoint is unity—are not true arithmetic
minimums and maximums. Instead, the minimum value represents the
measurement closest to –0 on a continuous scale of –0 to 1.00 to +0. The
maximum value is the measurement closest to +0 on the same scale.
Figure 8-1 shows the min/max values in a typical environment, assuming a
positive power flow. In figure 8-1, the minimum power factor is –.7 (lagging)
and the maximum is .8 (leading). It is important to note that the minimum
power factor need not be lagging, and the maximum power factor need not be
leading. For example, if the power factor values ranged from –.75 to –.95, then
the minimum power factor would be –.75 (lagging) and the maximum power
factor would be –.95 (lagging). Likewise, if the power factor ranged from +.9
to +.95, the minimum would be +.95 (leading) and the maximum would be
+.90 (leading).
See Changing the VAR Sign Convention in Appendix E for instructions on
changing the sign convention over the communications link.
To Next Page
Loading...
Need help?
General
