1. Check that the IED settings are appropriate, for example the PUFrequency, VMin,
and the tDelay.
2. Supply the IED with three-phase voltages at rated values.
3. Slowly decrease the magnitude of the applied voltage, until the BLKDMAGN signal
appears.
4. Note the voltage magnitude value and compare it with the set value VMin.
5. Slowly decrease the frequency of the applied voltage, to a value below
PUFrequency.
6. Check that the PICKUP signal does not appear.
7. Wait for a time corresponding to tDelay, make sure that the TRIP signal does not
appear.
11.7.1.2 Completing the test
Continue to test another function or end the test by changing the TESTMODE setting to
Disabled. Restore connections and settings to their original values, if they were changed
for testing purposes.
11.7.2 Overfrequency protection SAPTOF (81)
Prepare the IED for verification of settings outlined in Section
"Preparing the IED to
verify settings".
11.7.2.1 Verifying the settings
Verification of PICKUP value and time delay to trip
1. Check that the IED settings are appropriate, for example the pickup value and the
time delay.
2. Supply the IED with three-phase voltages at their rated values and initial frequency.
3. Slowly increase the frequency of the applied voltage with a 40 mHz step, applying
it for a period that is 10% longer than tDelay.
4. Note the trip value and compare it with the set value.
5. Decrease the frequency to rated operating conditions.
6. Check that the PICKUP signal resets.
7. Set the frequency to 20 mHz under the trip value.
8. Increase the frequency with a 40 mHz step, applying it for a period that is 10% longer
than tDelay.
9. Measure the time delay for the TRIP signal, and compare it with the set value. Note
that the measured time consists of the set value for time delay plus minimum trip
time of the pickup function (80 - 90 ms).
Section 11 1MRK 504 165-UUS -
Testing functionality by secondary injection
224 Transformer protection RET670 2.2 ANSI
Commissioning manual
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