MIL-HDBK-1133
Nameplate Capacity (kVA) = total installation
transformer capacity
Division factor
= 2.0
The diversity factor (ratio between the individual maximum
demands and the coincident maximum demand) is applied at a value
of 2.0 to all transformers based on the National Electric Code
diversity factor allowances (The National Electrical Code
Handbook: Based on the 1999 Edition of the National Electrical
Code, Earley et al., 1999).
2.6.2.2
Load Variations. Variations in electrical consumption
can exist hourly (within a 24-hour day), seasonally (primarily
summer/winter), and by electrical feeder loading. These load
variations affect actual losses and should be accounted for, if
known. Seasonal, monthly, or feeder variations can be accounted
for by calculating the various loading factors needed for this
analysis for each season, month, or feeder. The 24-hour
variations are generally constant for most energy use except
cooling and are impractical to calculate for each separate day.
Therefore, another factor (FLD) accounts for the effects of daily
load variations and the I2R nature of the resistive loss, using
the average and peak loads that are easily acquired from utility
and installation sources. Equation 3 gives the formula for
calculating this load factor. The equation is based on data
developed in Gnen (1986).
Average Load ( kW )
F LD = Load Factor =
Peak Load ( kW )
(3)
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