5. ELECTRICAL UTILITY SYSTEM
a. Description. Electrical utility systems consist of main power plants, substations,
switch-gear, transformers, vaults, manholes, utility and power poles, overhead and underground
conductors, and all associated hardware. Power is supplied by either station power plants, or
obtained from local civilian sources, and distributed throughout the station via substations,
switch-gear, and utility lines.
A variety of voltages are found throughout the Navy, ranging from 4kV to 60kV, with
conductors from #6 AWG to 800 MCM. Three basic types of distribution systems exist; (1)
the radial, (2) the loop, and (3) the network.
The radial system is a basic independent feeder line that branches out to several
distribution centers without intermediate connections between feeders. This is the simplest and
cheapest to construct, but also the least efficient.
The loop system starts at the substation and is connected to, or encircles, an area that
serves one or more distribution transformers or load centers; the conductors of the system
return to the same substation. This system is more reliable than the radial system, but costs
more and is more labor intensive to maintain.
The network system uses the independent feeder system of the radial system to supply
power to the distribution transformers, and parallels the secondaries that use the loop concept,
which allows for optimum flexibility and efficiency. A part or all of these three systems will
be found through out the Navy System.
b. Nonrepairable Components. Nonrepairable items compose the larger portion of the
electrical distribution system which will probably receive damage in the event of hostile attack.
These items normally require replacement or alternate items to be used. The following is a list
of the items which probably will not be repairable:
(7) Lightning Protection
(8) Power Plant
(6) Switch Gear
Electrical lines and conductors, and cables are normally the extent of the repairable items
of an electrical utility system, although some switch-gear and miscellaneous hardware may be
repairable, depending upon the extent of damage. For the purpose of expedient repair, this
publication primarily deals with repair of overhead and underground power lines and conductors.
Complete expedient ABFC-type stand-alone facilities are available for use as a substitute system
(see chapter 4).
c. Repairable Components. Within the electrical distribution system only a few items
will be of repairable nature. Depending on the amount of destruction received on station, and
on the amount of available resources, the following is a list of the most probable items which
(3) Grounding Wires
will be repairable:
(2) Guy Wires