Siemens Reyrolle 7SR5 - Page 431

to avoid inadvertent operation of other functions. Particular care should be taken when testing overcurrent
functions that the thermal rating of the current inputs is not exceeded.
Instantaneous Overcurrent – Phase (50)
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.
Phase Dir. I
set
(Amps) DTL (sec) P.U.
Current
Amps
Tolerence Op. Time 2 ⋅
I
set
Tolerance
CT1(I
A
)
CT2(I
B
)
CT3(I
C
)
Check correct indication, trip output, alarm contacts, waveform record.
Time Delayed Overcurrent – Phase (51)
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.
Gradually reduce current until the element drops off and record the level.
Table 9-4
P.U. D.O. & Timing Tests
Phase Dir Char.
Curve
I
set
(Amps)
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.
Element Blocking
The phase overcurrent elements can be blocked by Binary Input Inhibit, VT Supervision and
Inrush Detector operation, as well as 79 Delayed Inhibit setting. 79 inst elements are often config-
Functional Tests
9.10 Protection Functional Tests
Reyrolle 7SR5, Transformer Protection Device, Device Manual 431
C53000-G7040-C015-1, Edition 11.2019