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; requirement 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 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 [3] [_____]
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
fault capacity at the power source or provide a
fault capacity on which to base the analysis.
Delete the unused option.
SECTION 16475A
Page 28
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