51N Calculated Earth Fault - Siemens Reyrolle 7SR5 Manual

Apply current in the following sequence, a) 2 times setting for a time to ensure element operation, b) Zero
current for the reset time above (xTm), c) 2 times setting for a time to ensure element operation. Check that
the second operation (c) is similar to the first (a) and in line with the expected operate time for the element at
this current level.
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.
Operate Time
(expected)
Check correct indication, trip output, alarm contacts, waveform record.
IEC Reset
If the element is configured as an IEC characteristic, it may have an IEC (decaying) reset delay applied.
IEC reset times from operated condition to fully reset are as follows for zero applied current and Time multi-
plier (Tm) = 1.0. The reset curve characteristic type and Tm is defined by the operating characteristic.
Curve
IEC-NI
IEC-VI
IEC-EI
IEC-LTI
Apply current in the following sequence, a) 2 times setting for a time to ensure element operation, b) Zero
current for the reset time above (xTm), c) 2 times setting for a time to ensure element operation. Check that
the second operation (c) is similar to the first (a) and in line with the expected operate time for the element at
this current level. 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.
Operate Time
(expected)
50N/51N Calculated Earth Fault
9.10.13
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions for simplicity. Calculated EF, Measured EF, Sensitive EF & Restricted EF protections
can be Enabled/Disabled individually or as groups in the Function Config menu.
Calculated EF elements can be separated from Measured/Sensitive EF by arrangement of the secon-
dary injection circuit by shorting/disconnecting CT4 Input.
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 (67N)
See 10 Technical Data
Reyrolle 7SR5, Transformer Protection Device, Device Manual
C53000-G7040-C015-1, Edition 11.2019
Reset Time Operate Time
(calculated) (measured)
First test (c)
Reset Time Operate Time
(calculated) (measured)
First test (c)
for testing details.
9.10 Protection Functional Tests
50 % Reset Time 50 % Operate
(calculated) Time (calcu-
lated)
Fully Operated to Reset with Zero Current Applied
& Tm = 1 (s)
9.7
43.2
58.2
80
50 % Reset Time 50 % Operate
(calculated) Time (calcu-
lated)
Functional Tests
50 % Operate
Time (meas-
ured)
Second Test (c)
50 % Operate
Time (meas-
ured)
Second Test (c)
435