Schneider Electric PM810 Manual De Usuario

Descargar
Página de 122
© 2011 Schneider Electric. All Rights Reserved.
PowerLogic
TM
 Series 800 Power Meter
63230-500-225A2
Chapter 4—Metering Capabilities
3/2011
28
Min/Max Values for Real-time Readings
When certain one-second real-time readings reach their highest or lowest value, the power 
meter saves the values in its non-volatile memory. These values are called the minimum 
and maximum (min/max) values.
The power meter stores the min/max values for the current month and previous month. 
After the end of each month, the power meter moves the current month’s min/max values 
into the previous month’s register space and resets the current month’s min/max values. 
The current month’s min/max values can be reset manually at any time using the power 
meter display or PowerLogic software. After the min/max values are reset, the power meter 
records the date and time. The real-time readings evaluated are:
NOTE: Min/Max values for Vng and In are not available from the display. Use the display to 
read registers (see “Read and Write Registers” on page 26
) or use PowerLogic software.
For each min/max value listed above, the power meter records the following attributes:
NOTE: Phase of recorded min/max only applies to multi-phase quantities.
NOTE: There are two ways to view the min/max values. 1- Use the power meter display to 
view the min/max values since the meter was last reset. 2- Use PowerLogic software to 
view a table with the instantaneous min/max values for the current and previous months.
Power Factor Min/Max Conventions
All running min/max values, except for power factor, are arithmetic minimum and maximum 
values. For example, the minimum phase A-B voltage is the lowest value in the range 0 to 
1200 kV that has occurred since the min/max values were last reset. In contrast, because 
the power factor’s midpoint is unity (equal to one), the power factor min/max values are not 
true arithmetic minimums and maximums. Instead, the minimum value represents the 
measurement closest to -0 on a continuous scale for all real-time readings -0 to 1.00 to +0. 
The maximum value is the measurement closest to +0 on the same scale. 
Figure 4–1 shows the min/max values in a typical environment in which a positive power 
flow is assumed. In the figure, the minimum power factor is -0.7 (lagging) and the maximum 
is 0.8 (leading). 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
-0.75 to -0.95, then the minimum power factor would be -0.75 (lagging) and the maximum 
power factor would be -0.95 (lagging). Both would be negative. Likewise, if the power factor 
ranged from +0.9 to +0.95, the minimum would be +0.95 (leading) and the maximum would 
be +0.90 (leading). Both would be positive in this case.
Min/Max Voltage L-L
Min/Max Reactive Power Total
Min/Max Voltage L-N
Min/Max Apparent Power Total
Min/Max Current
Min/Max THD/thd Voltage L-L
Min/Max Voltage L-L, Unbalance
Min/Max THD/thd Voltage L-N
Min/Max Voltage L-N, Unbalance
Min/Max THD/thd Current
Min/Max Total True Power Factor
Min/Max Frequency
Min/Max Total Displacement Power 
Factor
Min/Max Voltage N-ground
(see the note below)
Min/Max Real Power Total
Min/Max Current, Neutral
(see the note below)
Date/Time of minimum value
Date/Time of maximum value
Minimum value
Maximum value
Phase of recorded minimum value
Phase of recorded maximum value