Inspection And Maintenance; Activities Before Performing Any Maintenance Of The Recloser Lv Unit; Additional Activities Before Performing Any Maintenance Of The Recloser Lv Unit; Removal Of Sel-751 Relay - ABB OVR-15 Instruction, Operation And Maintenance Manual

I N S TA L L AT I O N , I N S P E C T I O N A N D M A I N T E N A N C E
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7 Inspection and maintenance

The OVR-15, 27 and 38 LV unit will require minimal
maintenance if handled properly. The frequency
of operation and local environmental conditions
should be considered when determining a
maintenance schedule.
To a large extent, the safety and successful
functioning of any apparatus or system connected
with the recloser depends on the proper
installation, commissioning, programming and
configuration of the unit.
To provide long, reliable service, the LV unit should
be inspected at regular intervals. Operating
experience, environmental conditions, the number
of operations and any unusual service conditions
should guide you in establishing a maintenance
schedule.
Maintenance work must only be carried out by
trained personnel who know and respect all safety
regulations. In addition, it is recommended that
ABB service personnel should be called in to check
the service performance and for repair work.
7.1 Activities before performing any maintenance
on the recloser LV unit
(Perform this in conjunction with instructions in the
HV unit instruction manual.)
1. OPEN the recloser with the emergency manual
trip (K69) handle. This enables the mechanical
as well as electrical block close (recloser cannot
be closed unless the K69 handle is manually
reset).
2. Confirm the recloser OPEN status on the SEL-751
relay HMI and on the mechanical ON/OFF
indicator on the HV cabinet.
3. Switch OFF all MCBs to disconnect AC auxiliary
power and battery backup. This will connect the
capacitors to the discharge circuit.
4. Wait until the capacitors are discharged to a
safe level (when the RED LED on the discharge
circuit stops glowing).
5. Thus, all the electrical controls/measurements
and protections/communications of the
recloser are switched OFF, and the recloser LV
cabinet is ready for maintenance.
7.2 Additional activities before performing any
maintenance on the recloser LV unit
1. Complete all activities described in section 7.1.
2. Ensure that the main circuit is properly
grounded.
3. Follow all safety practices required by national
and local codes as well as company policies.
7.3 Removal of the SEL-751 relay
Once the SEL-751 relay is powered OFF, open the
inner door. Remove the connector with wiring.
Loosen the four screws from the back of the relay.
Gently remove the relay and gasket.

7.4 Removal of batteries

Adhere to the mandatory safety procedures as
outlined in section 1.0 of this document. Follow
the steps outlined below if required to remove
the batteries.
Before physically removing the batteries from the
LV unit, ensure that the battery MCB is OFF and the
battery connections are completely removed from
battery terminals.
1. Switch off the battery MCB.
2. Disengage male/female in the battery circuit.
3. Remove the M6 hex head screws A, B and C.
4. Remove the battery temperature sensor by
disengaging the male/female connectors.
5. Remove the entire battery assembly and then
remove the clamps by removing M6 hex head
screws D and E.
6. Remove batteries B1 and B2 in the direction
shown in figure 11.
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