Every four to six years• Periodic maintenance test for protection IEDs of objects with redundantprotection system.First maintenance test should always be carried out after the firsthalf year of service.When protection IEDs are combined with built-in control, the testinterval can be increased drastically, up to for instance 15 years,because the IED continuously reads service values, operates thebreakers, and so on.13.2.1 Visual inspection SEMOD56525-5 v3Prior to testing, the protection IEDs should be inspected to detect any visibledamage that may have occurred (for example, dirt or moisture deposits,overheating).Make sure that all IEDs are equipped with covers.13.2.2 Maintenance tests SEMOD56534-1 v1SEMOD56528-5 v5To be made after the first half year of service, then with the cycle as proposedabove 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 personnelmay test one IED at a time on live circuits where redundant protection is installedand de-energization of the primary circuit is not allowed.ABB protection IEDs are preferably tested by aid of components from theCOMBITEST testing system described in information B03-9510 E. Maincomponents are RTXP 8/18/24 test switch usually located to the left in eachprotection IED and RTXH 8/18/24 test handle, which is inserted in test switch atsecondary testing. All necessary operations such as opening of trip circuits, short-circuiting of current circuits and opening of voltage circuits are automaticallyperformed in the right order to allow for simple and safe secondary testing evenwith the object in service.13.2.2.1 Preparation SEMOD56528-10 v2Before starting maintenance testing, the test engineers should scrutinize applicablecircuit diagrams and have the following documentation available:Section 13 1MRK 505 378-UEN ACommissioning and maintenance of the fault clearing system278 Line differential protection RED670 2.2 IECCommissioning manual
