Operation Guide P341/EN O/B11
Commissioning and CHAPTER 3
Maintenance Page 23/80
MiCOM P341
8. MAINTENANCE
8.1 Maintenance period
It is recommended that products supplied by ALSTOM T&D Ltd. receive periodic
monitoring after installation. As with all products some deterioration with time is
inevitable. In view of the critical nature of protective relays and their infrequent
operation, it is desirable to confirm that they are operating correctly at regular
intervals.
ALSTOM protective relays are designed for a life in excess of 20 years.
MiCOM P341 Interconnection Protection Relays are self-supervising and so require
less maintenance than earlier designs of relay. Most problems will result in an alarm
so that remedial action can be taken. However, some periodic tests should be done
to ensure that the relay is functioning correctly and the external wiring is intact.
If a Preventative Maintenance Policy exists within the customer’s organisation then the
recommended product checks should be included in the regular programme.
Maintenance periods will depend on many factors, such as:
• the operating environment
• the accessibility of the site
• the amount of available manpower
• the importance of the installation in the power system
• the consequences of failure
8.2 Maintenance checks
Although some functionality checks can be performed from a remote location by
utilising the communications ability of the relays, these are predominantly restricted to
checking that the relay is measuring the applied currents and voltages accurately,
and checking the circuit breaker maintenance counters. Therefore it is recommended
that maintenance checks are performed locally (i.e. at the substation itself).
BEFORE CARRYING OUT ANY WORK ON THE EQUIPMENT, THE USER
SHOULD BE FAMILIAR WITH THE CONTENTS OF THE SAFETY AND
TECHNICAL DATA SECTIONS AND THE RATINGS ON THE EQUIPMENT’S
RATING LABEL.
8.2.1 Alarms
The alarm status LED should first be checked to identify if any alarm conditions exist.
If so, press the read key [&] repeatedly to step through the alarms. Clear the alarms
to extinguish the LED.
8.2.2 Opto-isolators
The opto-isolated inputs can be checked to ensure that the relay responds to their
energisation by repeating the commissioning test detailed in Section 4.2.5 of this
chapter.
8.2.3 Output relays
The output relays can be checked to ensure that they operate by repeating the
commissioning test detailed in Section 4.2.6 of this chapter.
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