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Frequency protection Chapter 11
Verifying settings by secondary
injection
5. Slowly decrease the frequency of the applied voltage, to a value be-
low
StartFrequency.
6. Make sure that the START signal not appears.
7. Wait for a time corresponding to tTrip, and make sure that the TRIP
signal not appears.
8.1.2 Completing the test
Continue to test another function or end the test session by changing the test mode setting to off.
Restore connections and settings to their original values, if they were changed for test purposes.
8.2 Overfrequency protection (PTOF, 81)
Prepare the terminal for verification of settings as outlined in section 1 "Overview" and section 2
"Preparing for test" in this chapter.
8.2.1 Verifying the settings
Verification of Start-value and time delay to operate
Procedure
1. Make sure that you have appropriate settings in the terminal, espe-
cially the Start-value and the definite time delay.
2. Supply the terminal with three-phase voltages at their rated values.
3. Slowly increase the frequency of the applied voltage, until the
START signal appears.
4. Note the operate value and compare it with the set value.
5. Decrease the frequency to rated operating conditions.
6. Make sure that the START signal resets.
7. Instantaneously increase the frequency of the applied voltage to a
value about 20% higher than the operate value.
8. Measure the time delay for the TRIP signal, and compare it with the
set value.
Extended testing
Procedure
1. The test above can be repeated to check the time to reset.
Verification of the low voltage magnitude blocking
Procedure
1. Make sure that you have appropriate settings in the terminal, espe-
cially the
StartFrequency, IntBlkStVal, and the tTrip.
2. Supply the terminal with three-phase voltages at their rated values.
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