ANSI Reset
If the element is configured as an ANSI characteristic, it may have an ANSI reset delay applied.
ANSI reset times from operated condition to fully reset are as follows for zero applied current and 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. 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)
Element Blocking
The 51CL overcurrent elements can be blocked by Binary Input Inhibit. This functionality should be
checked.
Element
BI Inhibits
51CL
Functional Tests
9.10 Protection Functional Tests
Reyrolle 7SR5, Transformer Protection Device, Device Manual 439
C53000-G7040-C015-1, Edition 11.2019
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