on the transformer] [secondary-selective type] [distributed-network type]
[spot-network type]. Substations shall be subassembled and coordinated by
one manufacturer and shall be shipped in complete sections ready for
connection at the site. Complete sections shall include incoming,
transformer, and outgoing sections and, where practicable, shall be shipped
as one unit.
2.9.1.1
Incoming Section
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Note: For normal reliability systems, the primary
distribution will be radial, and the incoming
section will be a single metal-enclosed, fused,
load-interrupter switch. Where greater reliability
is required and there are two incoming primary
feeders, a selector switch or a duplex switch will
be specified.
A selector switch contains a non-loadbreak
incoming-line selector switch unit in series with a
separate interrupter unit. The interrupter unit
must be open before the selector unit may be
changed; the entire metal-enclosed switch assembly
is contained in one vertical section of switchgear.
A duplex switch contains 2 fully rated interrupter
switches connected together at their load side, and
requires 2 vertical sections of switchgear.
At installations where space is very tight, the
selector switch should be specified, otherwise the
duplex switch is preferable and should be specified.
Voltage ratings are listed in IEEE C37.20.3, Table
1. See TM 5-811-1/AF AFJMAN 32-1080 for guidance.
Specify current ratings based upon short-circuit
study.
Delete reference to SF6 insulating dielectric when
not required.
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Metal-enclosed interrupter switchgear consisting of fused, [air-insulated]
[vacuum-insulated] [SF6-insulated], interrupters in series with automatic,
visible blade disconnects shall be provided for protection of incoming
circuits. [SF6 gas shall conform to ASTM D 2472]. Metal-enclosed
interrupter switchgear shall comply with IEEE C37.30 for load-interrupter
switches, NEMA SG 2 for power fuses, and shall be of the outdoor no-aisle
type that meets or exceeds the requirements of applicable publications
listed. Switch construction shall be of the manually-operated,
"OPEN-CLOSED," [air-insulated][vacuum-insulated][SF6-insulated], load
interrupter type equipped with a stored energy operator for quick-make
quick-break to make operating speeds independent of manual switch
operations. Where indicated, suitable bus or lug connections shall be
provided to mount field-installed, slip-on, medium-voltage cable
terminations for cable entering via conduit from below [and a flanged
throat suitable for direct connection to the associated transformer] [and a
bus throat suitable for connection to the associated metal-enclosed bus].
[Surge protection shall be provided in accordance with paragraph SURGE
ARRESTERS.] [Switches shall be of the 2-position type, open-closed.]
SECTION 16375A
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