ABB REG670 Commissioning Manual page 97

1MRK 502 073-UUS A
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062
Commissioning manual
Calibrating injection based 100% stator earth fault protection
6. Apply for example 10kΩ fault resistance.
6.1. Make sure that it is correctly measured.
6.2. Try to change the Viewed quantity to Fault resistance as 10kΩ is
relatively small.
You should be able to measure approximately 10kΩ here. If you choose to
view fault conductance, the measurement corresponds to approximately
-4
1×10 Mho.
7. Apply another known fault, say 1kΏ and verify that it is measured correctly.
8. Apply a short circuit and monitor the measurement: the measured resistance shall
be close to 0Ω; the value of this measurement is an offset that will affect all
performed measurements. If this value deviates from zero more than 10% of the
Trip setting, a new calibration shall be performed with a better calibration
resistance at the second step: that may increase the accuracy of measurements.
9. When you are completely sure that the function measures correctly, stop the
measurements and remove any applied faults.
Previously it was verified that the function measures correctly by applying known
faults and observing the graph during monitoring. Besides measuring the fault
size a trip indication is required when a large fault is measured to prevent that a
damage to the generator occurs. To allow the specific function to issue a trip
indication, it must first be enabled:
9.1. Select the Enable Function Tripping button in the ICT toolbar.
9.2. Choose Yes in the pop-up message.
ICT now writes this to IED.
9.3. By default the trip level is set to 1kΩ. In other words, if the fault resistance
is lower, then the function issue trips.
10. Verify the measurements by applying various faults.
Trip indication shall be visible in the ICT toolbar.
11. Verify that TRIP and ALARM signals are connected to tripping/alarming/
signaling/communication in accordance with the scheme design.
It is very important that the Function Tripping is Enabled under the
following situations:
• After completion of the calibration step
• Before leaving the ICT Tool
Section 7
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