Siemens 7SR51 - Page 486

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.
Table 9-9 P.U. D.O. & Timing Tests
Ph. Dir Char.
(NI EI VI
LTI,
DTL)
I
set
(A) Tm Operate Current Operate Time
P.U.
(Amps)
D.O.
(Amps)
Tol 2 ⋅ I
set
(sec)
5 ⋅ I
set
(sec)
Tol
CT1(I
A
)
CT2(I
B
)
CT3(I
C
)
Calculated timing values in seconds for Tm = 1.0
Curve 2 ⋅ I
set
5 ⋅ I
set
IEC-NI 10.03 4.28
IEC-VI 13.5 3.38
IEC-EI 26.67 3.33
IEC-LTI 120 30
ANSI-MI 3.8 1.69
ANSI-VI 7.03 1.31
ANSI-EI 9.52 1.3
Note that the operate time may be subject to the Minimum Op Time setting for the element and/or may
have a Follower DTL applied.
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.
Functional Tests
9.9 Protection Functional Tests
486 Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019