Installation; Tests Before Installation; Vacuum Test Procedure - ABB OVR-15 Instruction, Operation And Maintenance Manual

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7 Installation

The OVR-15, 27 and 38 recloser can be installed in a
substation frame or pole-mounting frame, or it can
be mounted into a customer-supplied structure.
Regardless of the frame or structure, all mounting
methods require the recloser to be vertical, leveled
and securely fastened. Follow your company
guidelines and applicable codes for setting the
height of the recloser, securing the frame to the
pole or foundation and making connections.
Before shipping from the factory, the OVR-15,
27 and 38 recloser HV unit is tested as a system
with its dedicated LV control cabinet. The HV unit
and LV control cabinet that were tested together
must be installed together. These units can be
properly matched by the serial number indicated
on each unit's rating plate.
• All metal mounting frames and structures
must be commonly grounded to the
grounding grid at the installation site.
• For proper operation of the electronic
components, the total impedance of the
grounding grid on site must be less than
one ohm (1 Ω).
• It is also mandatory to ensure that all
grounding connections to the welded star
grounding pad inside the LV cabinet are
always intact and secured.
• Be careful not to bend the cable beyond
a radius of 12 inches to avoid damage
to the cable.

7.1 Tests before installation

7.1.1 Vacuum test procedure

It is recommended to conduct a one-minute
power frequency voltage withstand test on each
interrupter to verify that there has been no loss
of vacuum during transportation or handling.
Experience indicates that a vacuum interrupter
with vacuum seal intact will withstand 40 kV AC
(80% of 50 kV) for OVR-15, 45 kV AC (80% of 60 kV)
for OVR-27 and 56 kV AC (80% of 70 kV) for OVR-38
across the open contacts. The same interrupter
with leaked vacuum (open to normal atmosphere)
will flashover at the gap at a much lower voltage.
Radiation warning
High voltage applied across an open gap in a
vacuum can produce X-ray radiation. However,
no radiation is emitted when the recloser is
closed because no gap exists. Also, X-ray
radiation at one meter is below the concern
level when the recloser is open to the specified
contact spacing during testing (within
specified voltages) or in normal service
conditions. Danger could exist at voltages
above those specified on the rating plate.
For testing, with recloser in open position, connect
all the three upper terminals together with jumpers.
Connect all three lower terminals together with
separate jumper, and ground them to cabinet
housing. Connect the high voltage to the top
terminals.
During testing, it is mandatory that:
• HV and LV cabinets are connected properly
with the control cable.
• Both HV and LV cabinets are securely grounded.
• LV cabinet is placed at least three meters away
from HV cabinet.
• Personnel must stand at least three meters away
from the apparatus before energizing the high
voltage source.
• Do not apply voltage for more than 60 seconds.
If internal flashover occurs, isolate the phases,
and test each one independently to identify
the defective interrupter. Any defective pole
assembly must be replaced prior to the recloser
being installed and placed into service.