Repeat the test with the reset time (b) reduced to 50 % of the previous value. Ensure that the second operate
time (c) is 50 % of the first (a) operate time.
Check correct indication, trip output, alarm contacts, waveform record.
50G/51G Measured Earth Fault
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions to avoid ambiguity. Calculated EF, Measured EF, Sensitive EF & Restricted EF protec-
tions can be Enabled/Disabled individually or as groups in the Function Config menu.
Measured EF elements can be separated from Calculated EF and Sensitive EF by secondary injection
of current through the CT4 input circuit only.
If any of these elements are defined as directional the correct voltage phase direction will be required to
produce an operation of those elements.
Directional Polarity (67G)
See 10 Technical Data for testing details.
MTA Forward Reverse
Lag (point C) Lead (point A) Lead (point B) Lag (point D)
Pick-up Drop-off Pick-up Drop-off Pick-up Drop-off Pick-up Drop-off
MTA -85 MTA +85 MTA -85 MTA -85
Measured
EF
Definite Time Overcurrent (50G)
If DTL setting is small, gradually increase current until element operates.
If DTL is large apply 0.9 times setting, check for no operation, apply 1.1 times setting, check operation.
Apply 2 times setting current if possible and record operating time.
Check correct indication, trip output, alarm contacts, waveform record.
Note that these elements can be set to directional.
Phase
Dir. I
set
(Amps) DTL (sec) P.U. Current
Amps
Op. Time 2 ⋅
I
set
Notes
CT4
If VTS action is set to Block, this option should be tested. Apply balanced voltage and current. Reduce a-
phase voltage to cause a VTS condition. Increase a-phase current and check that the element does not
operate.
If VTS action is set to Non-Directional, this option should be tested. Apply balanced voltage and current.
Reduce a-phase voltage to cause a VTS condition. Increase a-phase current and check that the element oper-
ates at its normal setting. Reverse the voltage phase direction whilst checking that the element does not reset.
Inverse Time Overcurrent (51G)
It will be advantageous to map the function being tested to temporarily drive the relevant pickup output in the
Pickup Config sub-menu in the Output Config menu as this will allow the Pickup LED to operate for
the function.
Gradually increase current until Pickup LED operates.
Apply 2 times setting current and record operating time.
Apply 5 times setting current and record operating time.
Compare to calculated values for operating times.
9.10.12
Functional Tests
9.10 Protection Functional Tests
Reyrolle 7SR5, Transformer Protection Device, Device Manual 433
C53000-G7040-C015-1, Edition 11.2019
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