Siemens 7SR45 Argus User Manual page 29

The following are the 51-n supported Curve Characteristic:
• DTL, IEC-NI, IEC-VI, IEC-EI, IEC-LTI, ANSI-MI, ANSI-VI, ANSI-EI
Operating time for IEC :
Operating time for IEEE/ANSI :
Reset time for IEC/IEEE/ANSI
Table 3-2
Curve type
IEC-NI 0.14
IEC-VI 13.5
IEC-EI 80
IEC-LTI 120
IEEE/ANSI - MI ----
IEEE/ANSI - VI ----
IEEE/ANSI - EI ----
Where,
I - Fault current Magnitude
I - Pickup setting
s
Tm - Time multiplier
Table 3-3
Parameters
Gn 51-n Element 51-1 Block
Gn 51-n Setting Pick-up current
Gn 51-n Char Characteristics
Gn 51-n Time Mult Time Multiplier
(other than DTL)
Delay
Gn 51-n Delay (Applicable only
for DTL)
Gn 51-n Min Minimum Operate
Operate Time
Gn 51-n Follower Follower DTL
Gn 51-n Reset Reset
©2018 Siemens Protection Devices Limited
K
α
t =
I
op
( )
1
Is
A
P
t =
I
op
( )
1
Is
R
t =
I
r
( )
:
1
Is
Constants for operating and reset curve characteristics
Operating time
K α P
0.02 ----
1.0 ----
2.0 ----
1.0 ----
---- 0.02
---- 2.0
---- 2.0
Time Delayed Overcurrent Protection (51-n)
Description Default Value
Disabled
1xI
n
IEC NI
1
5 s
0 s
0 s
0 s
Chapter 1 - 7SR45 Description of Operation
X Tm
+ B
X Tm
n
X Tm
A B
---- ----
---- ----
---- ----
---- ----
0.0515 0.114
19.61 0.491
28.2 0.1217
Min Max
- -
0.2xI 2.0xI
n
- -
0.01 s 10
0 s 15 s
0 s 20 s
0 s 20 s
60, IEC/
0 s ANSI
DECAY
Reset time
R n
9.7 2
43.2 2
58.2 2
80 2
4.85 2
21.6 2
29.1 2
Step Change
-
0.01
n
-
0.01
0.01
0.01
0.01
1
Chapter 1 Page 26 of 48