Areva MiCOM P225, Technical Manual

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P225/EN FT/B11 User Guide
Page 50/52 MiCOM P225
The operator can acknowledge the alarms using the
"
key. Keying in the password is not
necessary. The operator can acknowledge each message one at a time, or acknowledge all
the messages by going to the end of the list and acknowledging all the messages by
pressing the
"
key.
N.B.: If an alarm has not been acknowledged, it will not be possible to view
the default display programmed by the operator.
4.13.2 The HARDWARE ALARM messages
The safety and availability of the MiCOM P225 relay can be improved by a cyclic autotest
procedure of both hardware and software. Each time the P225 relay is switched on, auto-
diagnostic tests are initiated: these tests deal with the output relays (engaging/triggering
tests), the microprocessor, the memories (EEPROM checksum calculation, RAM tests) and
the acquisition circuit of each analogue input.
The hardware faults are split into 2 groups:
•
Minor faults: these are faults classified as non serious (communication fault, analogue
output fault, 3.6V battery, RTD or thermistor failure and internal clock).
•
Major faults: these are serious faults (RAM fault, EEPROM data fault, EEPROM
calibration fault, analogue signal acquisition fault, watchdog fault).
Any major fault recorded is immediately the subject of an alarm and provokes the activation
of the WATCHDOG relay (relay WD, terminals 35-36-37), as well as the switching off of the
other output relays.
The acknowledged alarms are all written to memory in the order of their appearance. The
display of the alarms is ensured in reverse chronological order (the most recent alarm first,
the least recent last). Each message is numbered and the total number of messages is
indicated in the top left hand corner of the display.
The operator can read all of the alarm messages using the
!
key, without any necessity to
key in the password.
The acknowledgement of the relay hardware alarm messages is IMPOSSIBLE. Only the
disappearance of the cause of the alarm will provoke their acknowledgement.
The display of a hardware fault (equipment fault) takes priority over the other alarms (non
equipment fault).
N.B.: In the case of major hardware alarm and when the trip output relay
RL1 has been configured latched, this relay drops out too.