Nexus 1250 - Demand Integrators

Doc# E107706 2 - 12
2: Meter Overview
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Electro Industries/GaugeTech
The Leader In Power Monitoring and Smart Grid Solutions
Watt hour (Wh): N = number of samples
VAR hour (VARh): N = number of samples
2.7: Demand Integrators
Power utilities take into account both energy consumption and peak demand when
billing customers. Peak demand, expressed in kilowatts (kW), is the highest level of
demand recorded during a set period of time, called the interval. The Nexus® 1250/
1252 supports the following most popular conventions for averaging demand and
peak demand: Block Window Demand, Rolling Window Demand, Thermal Demand,
and Predictive Window Demand. You can program and access all conventions
concurrently with the Communicator EXT
TM
software (see the Communicator EXT
TM
4.0 and MeterManager EXT Software User Manual).
Block (Fixed) Window Demand:
This convention records the average (arithmetic mean) demand for consecutive time
intervals (usually 15 minutes).
Example: A typical setting of 15 minutes produces an average value every 15 minutes
(at 12:00, 12:15. 12:30. etc.) for power reading over the previous fifteen minute
interval (11:45-12:00, 12:00-12:15, 12:15-12:30, etc.).
Rolling (Sliding) Window Demand:
Rolling Window Demand functions like multiple overlapping Block Window Demands.
The programmable settings provided are the number and length of demand subinter-
vals. At every subinterval, an average (arithmetic mean) of power readings over the
subinterval is internally calculated. This new subinterval average is then averaged
Wh
W
t
sec hr
t
N
¦
()
/
3600
1
VARh
VAR
t
sec hr
t
N
¦
()
/
3600
1