3 demand metering – GE Industrial Solutions Entellisys System User Manual User Manual
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Metering
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Watts and watt-hours are positive when the current is flowing from line to load and negative
when the current is flowing from load to line. Vars and var-hours are positive when the current is
lagging the voltage and negative when the current is leading the voltage.
The power factor is positive (i.e., lagging) when watts and vars have the same sign and negative
when watts and vars have the opposite sign. Minimum and maximum comparisons are done
based on magnitudes (e.g., a power factor of –0.866 is greater than a power factor of 0.707).
4.3 Demand metering
Demand metering is an optional feature in Entellisys. Demand metering can be enabled for
each circuit breaker, up to the maximum number of purchased demand metering options. When
the demand metering option is enabled, Entellisys provides the following quantities:
• All quantities available with the expanded metering option
• Previous interval kilowatt (kW) demand
• Maximum kW demand
• Previous interval kilovar (kvar) demand
• Maximum kvar demand
• Previous interval kVA demand
• Maximum kVA demand
• Demand logging – kWh, kvarh, kW demand, kvar demand, power factor
Per phase quantities are only available for wye connected systems.
Demands are averages over a demand interval. Entellisys supports both block and rolling
demand intervals:
Table 4-1 Demand interval and subinterval combinations supported in Entellisys
Subintervals per
interval
Subinterval length, minutes
1
2
3
4
5
6
10
15
20
30
60
1 (block demand)
X
x
x
x
x
x
x
x
x
x
x
2
x
x
x
x
x
x
x
x
3
x
x
x
x
x
x
4
x
x
x
x
5
x
x
x
x
x
6
x
x
x
x
10
x
x
x
x
12
x
x
x
x
x