Logger feature
Currently measured
impedance and its
average
Selectable quantity for
plotting
Selectable graph
update period
Currently used reference
IEC11000050-1-en.vsd
GUID-DCE099B6-4DBA-4A52-9566-0E20B8AF7712 V1 EN-US
Figure 25: Monitoring tab
2.
Set the graph update period to one second by typing 1 into the Graph update period
field.
3.
To start continuously plotting values on the graph with one second interval, select Start
reading values from IED.
By default the measured absolute impedance is plotted, however there are several items
that can be viewed when monitoring. To see these ones, select the available quantities
under the Viewed quantity drop-down menu under the Monitoring tab.
4.
Observe the fault conductance while applying known faults.
Both the calibration factors and the reference that is used can be verified this way. In
some cases though, it is desired to be able to measure/view other quantities.
5.
Select Fault conductance in the Viewed quantity drop-down menu.
The fault conductance is equal to 1/fault resistance, and is more suitable to view when no
faults or very high values of fault resistance are applied/measured.
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
.
6.
Apply for example 9kΩ fault resistance.
6.1. Make sure that it is correctly measured.
6.2. Try to change the Viewed quantity to Fault resistance in order to verify the value of
the applied test resistance.
You should be able to measure approximately 9kΩ here. If you choose to view fault
conductance, the measurement corresponds to approximately 1.11×10
-4
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.
1MRK 502 067-UEN B
Section 7
Calibrating injection based 100% stator earth fault protection
71
Commissioning manual
