of facilities to be constructed. Facilities having
a relatively-low power demand (e.g., 2,500 kVA or
less) generally require protection of: an incoming
aerial distribution line or underground
medium-voltage feeder; low-voltage feeders to
individual items of equipment, or to power
distribution equipment; and branch circuits. More
complex projects such as facilities with generating
capacity, large motors, or larger load demands, will
require more detailed and extensive coordinated
power system protection.
Independent of the type or types of facilities or
load demands, the coordinated power system
protection will be based on: economics, simplicity,
and the electrical power availability dictated by
the Using Agency or Service, or by the functional
use of the facilities or utilities; required to
provide maximum power service with a minimum of
power interruptions; and the operating speed of
protective devices required to minimize damage to
electrical components or items of equipment and to
prevent injury to personnel and nuisance tripping.
Unless otherwise approved, a dc power source will be
shown and specified to ensure proper closing and
tripping of protective devices which require a
reliable power source during outage of the normal
alternating-current power source.
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Analyses shall be prepared to demonstrate that the equipment selected and
system constructed meet the contract requirements for equipment ratings,
coordination, and protection. They shall include a load flow analysis, a
fault current analysis, and a protective device coordination study. The
studies shall be performed by a registered professional engineer with
demonstrated experience in power system coordination in the last three
years. The Contractor shall provide a list of references complete with
points of contact, addresses, and telephone numbers. The selection of the
engineer is subject to the approval of the Contracting Officer.
2.14.1
Scope of Analyses
The fault current analysis, and protective device coordination study shall
begin at: [the source bus and extend down to system buses where fault
availability is 10,000 amperes (symmetrical) for building/facility 600 volt
level distribution buses.] [the source bus and extended through the
secondary side of transformers for medium voltage distribution feeders.]
[the source bus and extend through [outgoing breakers] [outgoing medium
voltage feeders, down to the individual protective devices for medium
voltage radial taps] [outgoing medium voltage feeders, through the
secondary side of transformers] [as indicated] for main electric supply
substations.] [the nearest upstream device in the existing source system
and extend through the downstream devices at the load end.]
2.14.2
Determination of Facts
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NOTE: Require the Contractor to obtain an available
SECTION 16311A
Page 65
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