Important components of FT test system are FT1, FTx, FT19, FT19RS, FR19RX switches
and assemblies as well as FT-1 test plug.
14.2.2.1 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
14.2.2.2 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.
14.2.2.3 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.
14.2.2.4 Alarm test
When inserting the test handle of RTXP or using FT plugs, the alarm and event signalling
is normally blocked. This is done in the IED by setting the event reporting to Disabled
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.
1MRK 504 165-UUS - Section 14
Commissioning and maintenance of the fault clearing system
Transformer protection RET670 2.2 ANSI 299
Commissioning manual
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