Switch-On-To-Fault (50Lc/Sotf); Figure 3-7 Logic Diagram: 50Lc Overcurrent Element - Siemens 7SR45 Argus User Manual

The following are the 51G-n supported Curve Characteristic:
·
DTL, IEC-NI, IEC-VI, IEC-EI, IEC-LTI, ANSI-MI, ANSI-VI, ANSI-EI
Table 3-6
Parameters Description
51G-n Element 51G-1 Block
51G-n Setting Current Set point
51G-n Char Characteristics
Time Multiplier
51G-n Time Mult
(other than DTL)
Delay
51G-n Delay (Applicable only for
DTL)
51G-n Min Minimum Operate
Operate Time
51G-n Follower
Follower DTL
DTL
51G-n Reset Reset
3.7

Switch-On-To-Fault (50LC/SOTF)

SOTF provides high-speed tripping when the relay is energized with short-circuit current or fault current.
SOTF function monitors the phase current for 10 AC cycles from the start-up of relay with CT power and trips
when any fault is detected as per the user settings. After 10 AC cycle, SOTF will not monitor current and does not
operate.
SOTF can be inhibited by assigning binary input.
Operation of the Switch-On-To-Fault elements can be inhibited from:
Inhibit 50LC
Gn 50 LC /SOTF
Enabled
Disabled
&
Inhibit 50LC
Gn 50 LC /
Measurement
IL1
IL2
IL3
© 2017 Siemens Protection Devices Limited
Instantaneous Measured Earth Fault Protection (51G-n)
Default Value
Disabled
0.5xIn
DTL
1
5 s
0 s
0 s
0 s
A binary input.
Gn 50 LC Setting
c
>
>
>
10 cycles
Figure 3-7 Logic Diagram: 50LC Overcurrent Element
7SR45 Description of Operation
Min Max
- -
0.1xIn 0.80xIn
- -
0.01 10
0 s 15 s
0 s 20 s
0 s 20 s
60, IEC/
0 s ANSI
DECAY
Chapter 1 Page 22 of 34
Step
Change
-
0.01
-
0.01
0.01
0.01
0.01
0.01
³1
General Pickup
³1
50LC