MIL-HDBK-1133
been calculated at various military installations (Griffis Air
Force Base Integrated Resource Assessment, Volume 2: Baseline
Detail, Dixon et al., 1993; Vandenberg Air Force Base Integrated
Resource Assessment, Volume 2: Baseline Detail, Halverson et al.,
1993; Robins Air Force Base Integrated Resource Assessment,
Volume 2: Baseline Detail, Kelleret al., 1993; Fort Irwin
Integrated Resource Assessment, Volume 2: Baseline Detail,
Richman et al., 1994). This can be a relatively small number
compared to other energy uses. However, if an accurate value is
desired, the methodology presented here can provide an estimate
with a minimum of required data.
2.6.1
Transformer Losses. Most transmission and distribution
system energy losses are due to transformer losses. Transformer
energy loss consists of no-load and load power losses. No-load
loss is the energy consumed by the transformer's magnetic field
during periods when the transformer is energized. This loss is
dependent on the device configuration and design, materials used,
and power voltage and frequency. These characteristics remain
constant during the loading cycle and, therefore, do not change
with transformer load measured in kilovoltamperes (kVA). Load
losses, on the other hand, are produced from resistance in the
conductor windings. These losses are a function of the total
transformer current and vary as a function of the square of the
transformer load.
2.6.2
Transformer Loss Calculations. Transformer loss
calculations include both the peak power demand and the annual
energy consumption. This distinction is particularly important
to assess the impact to the overall electrical consumption,
because both demand and energy are billed separately. The peak
transformer demand includes the no-load and load losses. Because
transformer loss is a function of load, the maximum transformer
loss is almost always coincident with the peak load consumed by
the installation.
20
Previous Page
