transformers, lines, cables, single-shunt capacitor
banks, and line-connected or tertiary connected
shunt reactors. Group-operated air-insulated
switches are available for voltages from 15 through
345 kV. Group-operated SF6-insulated switches are
available for voltages ranging from 15 thru 230 kV.
Refer to TM 5-811-1 for guidance regarding
Group-Operated Line Switches.
**************************************************************************
Group-operated line switches shall be [air-insulated] [SF6 insulated] with
[manual] [and] [motor] -type operators. Group-operated line switches shall
comply with ANSI C37.32, IEEE C37.30, IEEE C37.34, and NEMA SG 6, and shall
be three-pole, single-throw, provided with a mechanism which opens the
three phases simultaneously. Group-operated switches shall be [manually
operated] [and] [motor operated] [as indicated].
a.
Air-Insulated:
Air-insulated switches shall be of the [vertical-break] [or] [side-break]
[or] [indicated-break] type, with either tilting or rotating insulators,
for [horizontal upright] [or] [vertical] [or] [horizontal underhung]
mounting [as indicated]. Contact surfaces shall be silver. The switching
capability required shall be of the [load interrupter] [or] [disconnecting]
type. Switches shall be provided with replaceable contacts, arc horns, and
other moving parts which have a limited life expectancy.
b.
SF6-Insulated:
Switches shall be puffer-type SF6 interrupters. The interrupter shall be
factory filled with SF6 gas and then permanently sealed. The interrupters
shall be driven by a single, stored-energy mechanism located at ground
level in an operator. The mechanism in the operator shall have
instantaneous trip-free capability (should the switch be inadvertently
closed into a fault).
c.
Load Interrupter Type, Air-Insulated:
Load interrupter switches shall be capable of interrupting load currents
equal to their continuous current ratings, which meet the requirements of
IEEE C37.30.
d.
Disconnecting Type, Air-Insulated:
Disconnecting switches shall be provided with quick-break arcing horns
rated for interrupting transformer exciting currents or line charging
currents, dependent upon the application. A switch used to protect a power
transformer shall be key-interlocked with its associated transformer's tap
changer for de-energized operation (TCDO) and its load side circuit breaker
disconnect, so that the manual TCDO can be operated only when the
transformer is de-energized, and so that the switch can be only opened or
closed after its associated circuit breaker has been placed in the open
position. A permanent warning sign having letters at least 50 mm 2 inches
high and reading as follows: "WARNING - DISCONNECTING SWITCH - DO NOT OPEN
UNDER LOAD" shall be mounted on the switch operating mechanism.
e.
Manually-Operated Type, Air-Insulated:
The switch operating handle shall be located approximately 1.1 m 3 feet 6
SECTION 16311A
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