15.3.2.1 Preparation
Before starting maintenance testing, the test engineers should scrutinize applicable
circuit diagrams and have the following documentation available:
•
Test instructions for protection IEDs to be tested
• Test records from previous commissioning and maintenance tests
• List of valid settings
• Blank test records to fill in measured values
15.3.2.2 Recording
It is of utmost importance to carefully record the test results. Special test sheets
covering the frequency of test, date of test and achieved test values should be used.
IED setting list and protocols from previous tests should be available and all results
should be compared for differences. At component failures, spare equipment is
used and set to the requested value. A note of the exchange is made and the new
measured values are recorded. Test records for several years of testing should be
stored in a common file for a station, or a part of a station, to give a simple
overview of the period of testing and achieved test values. These test records are
valuable when analysis of service disturbances shall be done.
15.3.2.3 Secondary injection
The periodic maintenance test is done by secondary injection from a portable test
set. Each protection shall be tested according to the secondary injection test
information for the specific protection IED. Only the setting values adopted shall
be checked for each protection function. If the discrepancy between obtained value
and requested set value is too big the setting should be adjusted, the new value
recorded and a note should be made in the test record.
15.3.2.4 Alarm test
When inserting the test handle the alarm and event signalling is normally blocked.
This is done in the IED by setting the event reporting to Off during the test. This
can be done when the test handle is inserted or the IED is set to test mode from the
local HMI. At the end of the secondary injection test it should be checked that the
event and alarm signalling is correct by activating the events and performing some
selected tests.
15.3.2.5 Self supervision check
Once secondary testing has been completed, it should be checked that no self-
supervision signals are activated continuously or sporadically. Especially check the
time synchronization system, GPS or other, and communication signals, both
station communication (61850/SPA/LON, and so on) and remote communication,
for example, the line differential communication system.
Section 15 1MRK 504 088-UEN C
Commissioning and maintenance of the fault clearing system
216
Installation and commissioning manual
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