16
15kV Class Padmount VisoVac™
instruction manual
MN024004EN April 2021
ote:
N
It may not be possible to complete steps 3 and
4 without de-energizing the upstream device. In
this case, step 3 and 4 can be skipped.
4. Open the Ground mechanism.
5. Close the Isolation mechanism.
6. Close the vacuum interrupter.
It is recommended not to remove any covers from the
VisoVac interrupter while the assembly is in service. If any
fasteners are loosened, the quality of the enclosure will be
compromised. If any repair is necessary, it is recommended
that the assembly be taken out of service and moved into
a controlled maintenance environment. If any cover is
removed for maintenance, new gasketing is required for
reassembly. The following list provides a list of cleaning,
testing and maintenance tasks for the vacuum interrupter
and related equipment.
●
Operation of breakers: After step 1 above, clean VCPT as
per the linked manual.
https://www.eaton.com/content/dam/eaton/products/
electrical-circuit-protection/medium-voltage-vacuum-
circuit-breakers/mv-vcp-t-vacuum-circuit-breakers/vcp-t-
vcp-tr-instruction-book-ib131016en.pdf
●
Heaters/thermostats: Heathers and thermostat shall be
cleaned after opening of interrupter.
●
Dielectric testing: Once the unit has left the factory
and been placed in service, subsequent dielectric tests
performed during maintenance should be performed at
75% of the rating per IEEE recommendation.
●
Follow these steps to perform the Pre-Startup inspection:
●
Inspect the equipment visually.
●
Make sure all connections are tightened and all covers
are closed before moving to next step.
●
Make surroundings neat and clean to prevent trip-and-
fall injuries.
Safety features
There are several safety interlocks built into the VisoVac
assembly to ensure the proper sequence of operations.
1. Vacuum interrupter to Isolating mechanism interlock
(V3 designs only)
a. The vacuum interrupter is mechanically interlocked
with the Isolating mechanism.
b. The vacuum interrupter will not close unless the
isolating rods are in the fully connected position.
c. If a tool is placed on the isolating rod mechanism,
the vacuum interrupter will trip open before any
electrical contact is broken.
2. Isolation mechanism to ground mechanism
a. The isolating mechanism is mechanically
interlocked with the ground mechanism.
b. When the isolating rods are in the connected
position, the ground rods are blocked from moving
and remain blocked until the isolating rods are in
the fully open position.
c. When the ground rods are in the connected
position, the isolating rods are blocked from
moving and remain blocked until the ground rods
are in the fully open position.
3. Ground mechanism to upstream device
a. It is imperative that there be no voltage present on
the cable bushings before closing the ground rods.
b. Since this requires opening the upstream device
that may be blocks or even miles away, it is
recommended that the user deploy their Lock-out/
Tag-out and/or operational procedures to ensure no
voltage is present before closing the ground rods.
4. Arc reduction maintenance system (ARMS)
(Digitrip 1150V only)
a. When the Arcflash Reduction Maintenance System
is enabled, the internal digital logic is bypassed by
a “faster than instantaneous” analog trip circuit
based on user preset values. In this mode, the
Digitrip is set to hair trigger and issues subcycle
tripping. Total clear is estimated within 4 cycles.
b. Eaton’s Arcflash Reduction Maintenance System
technology is based on the realization that when
working on energized electrical equipment, a fault
that occurs within the gear or downstream needs
to be cleared as quickly as possible. While this
seems obvious, in actual installations, intentional
delays are included in upstream devices to ensure
selective coordination with downstream devices.
This means that if a fault were to occur inside the
equipment the downstream breaker may never
clear the fault regardless of how much delay is or
isn’t programmed in the upstream device. While
other Eaton Arcflash technologies are available, the
Arcflash Reduction Maintenance System comes
standard with the Digitrip 1150 V. This patented
technique provides “faster than instantaneous”
clearing times.
See the following link for literature on the Digitrip 1150V
ARMS functionality:
https://www.eaton.com/content/dam/eaton/products/
electrical-circuit-protection/medium-voltage-vacuum-circuit-
breakers/mv-vcp-t-vacuum-circuit-breakers/digitrip-1150v-
with-maintenance-mode-il66a7535.pdf
