Due to the fact that no fault theoretically equals infinite fault resistance and
viewing this only plots unreliable values, it is better to view the fault
conductance, which is zero in this case.
As no fault is applied, the measured fault conductance must be close to zero.
Confirm this by viewing the graph.
It may be necessary to zoom in or out to properly view the measurements. For
instructions on this, see
Editing features in graph.
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
1×10
-4
Mho.
7. Apply another known fault, say 1kΏ and verify that it is measured correctly.
8. 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:
8.1. Select the Enable Function Tripping button in the ICT toolbar.
8.2. Choose Yes in the pop-up message.
ICT now writes this to IED.
8.3. By default the trip level is set to 1kΩ. In other words, if the fault resistance
is lower, then the function issue trips.
9. Verify the measurements by applying various faults.
Trip indication shall be visible in the ICT toolbar.
10. 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
7.7 Auditing
During installations, calibrations and commissions the ICT generates reports for each
of the steps and collects them under the Auditing tab. See the procedures below on
how to view and delete reports as well as generate logs from reports.
Section 7 1MRK502053-UEN B
Calibrating injection based 100% stator earth fault protection
80 Generator protection REG670 2.0 IEC
Commissioning manual
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