Definite Time Overcurrent. (50); Inverse Time Overcurrent. (51) - Siemens Argus 7SR21 Technical Manual

7SR210 & 7SR220 Commissioning & Maintenance Guide
2.2.1

Definite Time Overcurrent. (50)

If DTL setting is small, gradually increase current until element operates.
If DTL is large apply 0.9x setting, check for no operation, apply 1.1x setting, and check operation.
Apply 2x setting current if possible and record operating time.
Is
Phase Dir.
(Amps)
I (I )
L1 A
I (I )
L2 B
I (I )
L3 C
Check correct indication, trip output, alarm contacts, waveform record.
2.2.2

Inverse Time Overcurrent. (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 Pick-up led to operate for the function.
Gradually increase current until Pickup LED operates.
Apply 2x setting current and record operating time,
Apply 5x 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.
Ph. Dir
P.U.
D.O.
I (I )
&
L1 A
TIMING
I (I )
L2 B
TESTS
I (I )
L3 C
Calculated Timing values in seconds for TM =1.0
Curve
IEC-NI
IEC-VI
IEC-EI
IEC-LTI
ANSI-MI
ANSI-VI
ANSI-EI
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.
Page 18 of 82
DTL P.U. Current
(sec) Amps
Char. Is
TM
Curve (A)
2 xIs
10.03
13.50
26.67
120.00
3.80
7.03
9.52
Operate Time
Tol
2 x Is
Operate Current
P.U. D.O.
Tol
(Amps) (Amps)
© 2013 Siemens Protection Devices Limited
Tol
Operate Time
2 x Is 5 x Is
Tol
(sec) (sec)
5 xIs
4.28
3.38
3.33
30.00
1.69
1.31
1.30