The normal maintenance practices of the user should be followed. However, ABB's
recommendation is as follows:
Every second to third year
• Visual inspection of all equipment.
• Removal of dust on ventilation louvres and IEDs if necessary.
• Periodic maintenance test for protection IEDs of object where no redundant
protections are provided.
Every four to six years
• Periodic maintenance test for protection IEDs of objects with redundant protection
system.
First maintenance test should always be carried out after the first half year
of service.
When protection IEDs are combined with built-in control, the test interval
can be increased drastically, up to for instance 15 years, because the IED
continuously reads service values, operates the breakers, and so on.
7.1.2.1 Visual inspection
Prior to testing, the protection IEDs should be inspected to detect any visible damage that
may have occurred (for example, dirt or moisture deposits, overheating). Should burned
contacts be observed when inspecting the IEDs, a diamond file or an extremely fine file
can be used to polish the contacts. Emery cloth or similar products must not be used as
insulating grains of abrasive may be deposited on the contact surfaces and cause failure.
Make sure that all IEDs are equipped with covers.
7.1.2.2 Maintenance tests
To be made after the first half year of service, then with the cycle as proposed above and
after any suspected maloperation or change of the IED setting.
Testing of protection IEDs shall preferably be made with the primary circuit de-energized.
The IED cannot protect the circuit during testing. Trained personnel may test one IED at
a time on live circuits where redundant protection is installed and de-energization of the
primary circuit is not allowed.
Section 7 1MRK 505 293-UUS A
Commissioning and maintenance of the fault clearing system
120
Commissioning manual
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