Symmetrical Current Tests, Address Block 4100 - Siemens 7UT51 Instruction Manual

18
Field Testing and Commissioning
On branch points, a low-voltage test source can be
used. Alternatively, load current test is possible.
Backup protection must be in service if current tests
are only possible under voltage.
The test current must be at least 2% of the rated relay
current.
When the 7UT513 is used on a protected object with
three terminals (three-winding transformers,
three-terminal branch points) or when a virtual object
is included, the test currents are always fed over two
sides: first Side 1 to Side 2, then Side 1 to Side 3.
Current tests are initiated by a measurement request
by the operator. The measured test values are stored
but not continuously actualized to ensure comparable
results. If the test arrangement is changed, a new
measurement request will be necessary.
Figure 18.2 Primary Current Test Arrangement Example
-
for a Three
During test operation, the differential protection or
restricted earth fault protection is not operational even
when they are switched On. When no activities are
carried out during more than 60 minutes such as no
measurement request or any change in the
Address Block 4100, the relay terminates the test
operation automatically. Of course, it is possible to
terminate test operation at any time.
198
Winding Transformer
18.3 Symmetrical Current
Tests,
Address Block 4100
The test can be initiated directly from the relay panel
or via WinDIGSI. These tests are located in
Address Block 4000. The commissioning
measurements for the differential protection in
Address Block 4100.
All measurement values are stored immediately after
the operator has started measurement request and
are available for readout. They are not actualized in
order to ensure comparable results. When the test
conditions have been changed, a new measurement
request must be started. For starting a measurement
request via the relay panel, the password is required.
The following tests refer to the relay front panel;
however, the same tests are easily performed using
WinDIGSI. To initiate this test with WinDIGSI, go to the
Test menu, choose Commissioning Test, and then
choose the required measurement. See Figure 18.3
for the WinDIGSI measured current test screen.
Go to Address Block 4000 and page to Address 4101
to test the differential current:
Address Test
4000 Tests
4100 Commission Test
4101
Test Diff? Enter Yes. Measurement is processed
The relay measures all currents and phase angle of
this test Address 4101. As soon as the first measured
value appears in the display, the test current can be
switched off. The values can be read out be
repeatedly depressing the No key, the Back Space key
allows reads the preceding value.
After start, the relay first checks whether
measurement can be carried out. If a protection
function has picked up before, measurement is
rejected. When the measured quantities are too small,
a corresponding message is given. In these cases,
Address 4101 must be left (by going back to 4100)
and the test arrangement must be rechecked.
Increase the test current if necessary. Finally go back
to Address 4101 and repeat the procedure.
7UT51 v3
PRIM-2330C