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63230-300-212 Chapter 4—Metering Capabilities
April 2001 Demand Readings
57
© 2001 Schneider Electric All Rights Reserved
Demand power is the energy accumulated during a specified period divided
by the length of that period. How the circuit monitor performs this calculation
depends on the method you select. To be compatible with electric utility billing
practices, the circuit monitor provides the following types of demand power
calculations:
• Block Interval Demand
• Synchronized Demand
The default demand calculation is set to sliding block with a 15 minute
interval. You can set up any of the demand power calculation methods from
the display or from
SMS. For instructions on how to setup the demand
calculation from the display, see “Setting Up the Metering Functions of the
Circuit Monitor” on page 16. See the
SMS online help to perform the set up
using the software.
In the block interval demand method, you select a “block” of time that the
circuit monitor uses for the demand calculation. You choose how the circuit
monitor handles that block of time (interval). Three different modes are
possible:
• Sliding Block. In the sliding block interval, you select an interval from 1 to
60 minutes (in 1-minute increments). If the interval is between 1 and 15
minutes, the demand calculation
updates every 15 seconds
.Iftheinterval
is between 16 and 60 minutes, the demand calculation
updates every 60
seconds
. The circuit monitor displays the demand value for the last
completed interval.
• Fixed Block. In the fixed block interval, you select an interval from 1 to 60
minutes (in 1-minute increments). The circuit monitor calculates and
updates the demand at the end of each interval.
• Rolling Block. In the rolling block interval, you select an interval and a
subinterval. The subinterval must divide evenly into the interval. For
example, you might set three 5-minute subintervals for a 15-minute
interval. Demand is
updated at each subinterval
. The circuit monitor
displays the demand value for the last completed interval.
Figure 4–3 below illustrates the three ways to calculate demand power using
the block method. For illustration purposes, the interval is set to 15 minutes.
Demand Power
Calculation Methods
Block Interval Demand