Alstom MiCOM P846, Technical Manual

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Troubleshooting P846/EN TS/D
MiCOM P846
(TS) 12-7
TS
6. ERROR CODE DURING OPERATION
The relay performs continuous self-checking. If an error is detected then an error message
will be displayed, a maintenance record will be logged and the relay will reset (after a 1.6
second delay). A permanent problem (for example due to a hardware fault) will generally be
detected on the power up sequence, following which the relay will display an error code and
halt. If the problem was transient in nature then the relay should reboot correctly and
continue in operation. The nature of the detected fault can be determined by examination of
the maintenance record logged.
There are also two cases where a maintenance record will be logged due to a detected error
where the relay will not reset. These are detection of a failure of either the field voltage or
the lithium battery, in these cases the failure is indicated by an alarm message, however the
relay will continue to operate.
If the field voltage is detected to have failed (the voltage level has dropped below threshold),
then a scheme logic signal is also set. This allows the scheme logic to be adapted in the
case of this failure (for example if a blocking scheme is being used).
In the case of a battery failure it is possible to prevent the relay from issuing an alarm using
the setting under the Date and Time section of the menu. This setting ‘Battery Alarm’ can be
set to 'Disabled' to allow the relay to be used without a battery, without an alarm message
being displayed.