6.5.3 Rate-of-change frequency protection SAPFRC (81)
Prepare the IED for verification of settings as outlined in
5.1 "Preparing the IED to verify
settings".
Values of the logical signals for SAPFRC (81) are available on the local HMI under Main
menu/Tests/Function status/Frequency/SAPFRC(81,df/dt)/SAPFRC:X. The Signal
Monitoring in PCM600 shows the same signals that are available on the local HMI.
6.5.3.1 Verifying the settings
PICKUP value and time delay to operate
1. Check that the appropriate settings are available in the IED, especially the PICKUP
value and the definite time delay. Set PickupFreqgrad, to a rather small negative
value.
2. Supply the IED with three-phase voltages at their rated values.
3. Slowly decrease the frequency of the applied voltage, with an increasing rate-of-
change that finally exceeds the setting of PickupFreqgrad, and check that the
PICKUP signal appears.
4. Note the operate value and compare it with the set value.
5. Increase the frequency to rated operating conditions, and zero rate-of-change.
6. Check that the PICKUP signal resets.
7. Instantaneously decrease the frequency of the applied voltage to a value about 20%
lower than the nominal value.
8. Measure the time delay for the TRIP signal, and compare it with the set value.
Extended testing
1. The test above can be repeated to check a positive setting of PickupFreqGrad.
2. The tests above can be repeated to test the RESTORE signal, when the frequency
recovers from a low value.
6.5.3.2 Completing the test
Continue to test another function or end the testing by setting the parameter TestMode to
Disabled under Main menu/Tests/IED test mode/TESTMODE:1. If another function is
tested, then set the parameter Blocked to No under Main menu/Tests/Function test
modes/Frequency/SAPFRC(81,df/dt)/SAPFRC:X for the function, or for each
individual function in a chain, to be tested next. Remember to set the parameter Blocked to
Yes, for each individual function that has been tested.
1MRK 505 293-UUS A Section 6
Testing functionality
85
Commissioning manual
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