ured to be blocked by the autoreclose Out state using logic. If applicable this functionality should be checked.
The characteristic can be modified by Cold Load (51-n only) and Voltage Controlled Overcurrent
and can be made non-directional by VT Supervision. This functionality should be checked.
Element BI Inhibits VTS Action 81HBL2 Inhibit 79 Delayed Inhibit
51-1
51-2
51-3
51-4
50-1
50-2
50-3
50-4
ANSI Reset
If the element is configured as an ANSI characteristic, it may have an ANSI decaying reset delay applied.
ANSI 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 Fully Operated to Reset with Zero Current Applied
& Tm = 1 (s)
ANSI-MI 4.85
ANSI-VI 21.6
ANSI-EI 29.1
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)
Reset Time
(calculated)
Operate Time
(measured)
50 % Reset Time
(calculated)
50 % Operate
Time (calcu-
lated)
50 % Operate
Time (meas-
ured)
First test (c) Second Test (c)
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
Fully Operated to Reset with Zero Current Applied
& Tm = 1 (s)
IEC-NI 9.7
IEC-VI 43.2
IEC-EI 58.2
IEC-LTI 80
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.
Functional Tests
9.10 Protection Functional Tests
432 Reyrolle 7SR5, Transformer Protection Device, Device Manual
C53000-G7040-C015-1, Edition 11.2019
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