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Equipment Description
Power/Vac® Metal-Clad Switchgear 5kV & 15kV
01.4IB.67000
devices. Copper rods are bolted in the location
normally occupied by vacuum interrupters.
The stationary structure is the same as for a
circuit breaker. When the device is fully racked
in, it connects the top set of metal-clad primary
disconnects to the bottom set.
An interlock system, consisting of a side
extension identical to the positive interlock
extension of a standard circuit breaker
when the breaker is closed, ensures that the
dummy element cannot be racked in or out
unless all sources to which it may connect are
deenergized.
A key lock is provided on the dummy element.
It takes a key which becomes available only
when all sources to which the dummy might
connect are deenergized. When the key is
available, the key interlock can be operated
to withdraw the positive interlock extension.
The dummy element now looks like an open
breaker and it can be racked in or out. As
long as the positive interlock extension is
withdrawn, the key is captured and it cannot
be released unless the dummy element is in
the CONNECTED or TEST position or completely
withdrawn. Hence, the sources to which the
dummy element may connect cannot be
re-energized until the dummy element is in
one of these three positions.
The key for the dummy element interlock will
usually be obtained from a transfer block at
which all the source keys are accumulated and
captured before the dummy element key can
be obtained.
Q. GROUND AND TEST DEVICE
This device is designed to make either the
upper or lower primary conductors in the
breaker unit readily accessible. The type PVV
manual ground and test device provides a
convenient means of grounding the cables
or the bus in order to safeguard personnel
who may be working on the cables or the
equipment. The device can used for applying
power for high-potential tests or for fault
location. It can be used to measure insulation
resistance (megger). By using voltage
transformers, it can also be used for phasing
out cables. Refer to the instruction bulletin
provided for this device. If “hotsticks” are used,
they should be insulated.
Note that the main switchgear bus is
connected to the lower studs when the device
is installed in an upper compartment and to
the upper studs when the device is installed in
a lower compartment.
In addition to the device described in this
section, there is a deluxe power-operated
type GMV device available which has a
self-contained bus or line selector switch and a
separately controlled, power operated,
three-phase grounding switch. The GMV
device is a dead-front design with mechanical
and electrical interlocks, provisions for remote
control and plug-type cable testing and
phasing. The primary conductors required for
grounding are self-contained, with no external
cable connections required.
The GMV device is designed for maximum
safety to personnel while accomplishing all
the basic required grounding and testing
functions. Refer to the specific ground and test
device instruction bulletin for more details.
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