Alstom MiCOM P846 Technical Manual Download

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Maintenance

P846/EN MT/D

MiCOM P846

(MT) 11-5

of the Commissioning section (P846/EN CM), inclusive of this section.

1.3.1.2

Replacing printed circuit boards and other internal components of protective relays must be

by Service Centers approved by Alstom Grid. Failure to obtain the

s for capacitors to discharge. It is also strongly recommended

son,

1.4

Re-calibration is not required when a PCB is replaced

unless it happens to be one of the

e input module;

the replacement of either directly affects the calibration.

refore

Each relay has a battery to maintain status data and the correct time when the auxiliary

maintained includes event, fault and disturbance records and

event of a low battery condition.

but do not replace

ty and technical data sections and the ratings on the equipment's

Open the bottom access cover on the front of the relay.

cket. If necessary, use a small, insulated screwdriver to

ng care to ensure that the polarity markings on the battery agree with those

nd safety approvals such as UL (Underwriters Laboratory), CSA

Once reinstallation is complete the relay should be re-commissioned using the instructions in
sections 1 to 8

Replacing a PCB

undertaken only
authorization of Alstom Grid After Sales Engineers prior to commencing work may invalidate
the product warranty.

Before removing the front panel to replace a PCB the auxiliary supply must be
removed, and wait 5
that the voltage and current transformer connections and trip circuit are isolated.

Alstom Grid Automation Support teams are available world-wide, and it is strongly
recommended that any repairs be entrusted to those trained personnel. For this rea
details on product disassembly and re-assembly are not included here.

Re-calibration

1.4.1

P846 relay

boards in th

Although it is possible to carry out re-calibration on site, this requires test equipment with
suitable accuracy and a special calibration program to run on a PC. It is the
recommended that the work be carried out by the manufacturer, or entrusted to an approved
service center.

Changing the relay battery

1.5

supply voltage fails. The data
the thermal state at the time of failure.

This battery will periodically need changing, although an alarm will be given as part of the
relay’s continuous self-monitoring in the

If the battery-backed facilities are not required to be maintained during an interruption of the
auxiliary supply, the steps below can be followed to remove the battery,
with a new battery.

Before carrying out any work on the equipment, the user should be familiar with the
contents of the safe
rating label.

Instructions for replacing the battery

1.5.1

Gently extract the battery from its so
prize the battery free.

Ensure that the metal terminals in the battery socket are free from corrosion, grease and
dust.

The replacement battery should be removed from its packaging and placed into the battery
holder, taki
adjacent to the socket.

Note:

Only use a type ½AA Lithium battery with a nominal voltage of 3.6V
a
(Canadian Standards Association) or VDE (Vereinigung Deutscher
Elektrizitätswerke).