TM5-811-1/AFJMAN
32-1080
CHAPTER 4
MAIN ELECTRIC SUPPLY STATIONS/SUBSTATIONS
4-1. Provisions.
to the new project than a modified existing station.
Conjunctive billing is required if there is more
At existing installations, new stations will be
than one point of service.
provided either when it is not possible or when it
(1) Locations near installation boundaries. At
is impractical to modify an existing station to
an existing installation any new station should be
serve both the existing facilities and the new
located as near as practical to the installation
projects. The decision to modify an existing station
boundary and be served by a single three-phase
or construct a new station will be made at the
utility line from the existing station if the utility
earliest practical stage of project planning.
source is adequate to serve both the existing and
a. Existing stations. Existing stations will be
new loads. New utility lines will be considered
modified when the estimated life cycle cost of the
only when the existing source (or sources) is
required modification is less than the estimated
inadequate; when a new line is required to comply
life cycle cost of a new station. This decision will
with the reliability, availability, or maintainabil-
be subject to review and approval by the Using
ity requirements of the Using Agency; when a new
Agency in coordination with the utility company
line is more cost effective than alternate methods;
or other owners, operators, and users of the sta-
or when there are other justifications. Multiple
tion. Factors to be considered in the decision to
power sources and two or more metering points
modify an existing station will include:
generally should be avoided.
(1) Availability of surplus capacity in the ex-
(2) Locutions remote to installation boundaries.
isting station and lines.
Location of a new station remote to the installa-
(2) Space available for required station modifi-
tion's boundary or the need for more than one new
cations.
main electric supply station/substation requires a
(3) Age and condition of existing equipment.
waiver from the Host Command for Air Force
(4) Location of the existing station with re-
projects. The request and justification for such a
spect to the new load.
waiver will be furnished to that office by the field
(5) Quantity, sizes, and rights-of-way for new
operating agency responsible for the design of new
transmission and distribution lines.
projects. Justifications will be based on cost effec-
(6) Adequacy of transmission and distribution
tiveness or other factors noted above and may
capacity.
include a discussion of the importance of new
(7) Need for voltage regulation or reclosing.
projects to national interests; probable conse-
(8) Megavolt amperes (MVA) interrupting and
quences and expenses over the life of the project
withstand ratings of station and line equipment.
for lost production or lost manufacturing efforts
(9) Protective device coordination for both ex-
associated with less reliable electrical services; or
isting and new equipment.
other reasonable causes that fully substantiate the
(10) Serving utility rate schedule.
more costly design addressed in the waiver re-
(11) Site-peculiar features that affect design,
quest.
construction, operations, and maintenance costs.
c. Rates. Based on the estimated demand and
(12) Capability of the modified station to meet
the using agency's requirements for safe, reliable,
usage, all electrical service rate schedules applica-
available, and maintainable electrical service.
ble to the project will be evaluated to ensure an
b. New stations. When a new station is contem-
adequate supply of electrical power at the lowest
plated at an existing installation served by a Main
available cost. Care will be taken to see that the
Electric Supply Station or Substation (a station is
chosen schedule compares favorably with that of
to be designated a "Main Electric Supply Station"
any other utility serving the area, and that the
when there is no power transformer and a "Main
rates are no higher than those paid by other
Electric Supply Substation" when power trans-
customers for similar service. The possibility of
formers constitute a station element), the total life
recovering any connection charges, by deducting a
cycle cost of station modifications with new distri-
certain percentage of each monthly bill by a fixed
bution facilities will be compared against the cost
annual or monthly refund should be investigated.
of a new, dedicated station with less extensive
Utility rates, contract coordination, and negotia-
distribution facilities, located in closer proximity
tions will be coordinated with the U.S. Army
4-1
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