SETTING AND COMMISSIONING
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NA10 - Manual - 04 - 2022
7.4 MAINTENANCE
The Pro-N relays do not require any particular maintenance; all circuits use high quality static com-
ponents, the subassembly products undergo dynamic checks on their functioning before the final
assembling of the complete equipment. The dedicated circuits and the firmware for the self-test
function continuously check the relay operation; the continuously operating auto-zeroing function
dynamically corrects the measuring errors due to offset, heat dependent drifts, aging of compo-
nents, etc. The processor is equipped with a watch-dog circuit which restores the correct operation
of the firmware in case of fault.
If the following criteria are properly implemented:
• comprehensive functional tests at commissioning,
• absence of significant modification on the protection system,
• activation and permanent remote control of self-test alarms through supervision,
• control of self-test undetectable failures (comparing of measures with the external instruments,
auxiliary voltage control, etc ..)
• analysis of the stored information (faults and events, and oscillographic records),
periodic checks can be avoided. In the absence of some of the criteria listed above, it is advisable to
perform periodic checks every five years.
7.5 REPAIR
No repair of possible faults by the client is foreseen; if following to any irregularity of operation, the
above tests confirm the presence of a fault, it will be necessary to send the relay to the factory for
the repair and the consequent settings and checks.
7.6 PACKAGING
The Pro-N devices must be stored within the required temperature limits; the relative humidity should
not cause condensation or formation of frost.
It is recommended that the devices are stored in their packaging; in the case of long storage, espe-
cially in extreme climatic conditions, it is recommended that the device is supplied with power for
some hours before the commissioning, in order to bring the circuits to the rating conditions and to
stabilize the operation of the components.
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