Derived Earth Fault Protection (50N); Figure 3-17 Logic Diagram: Derived Instantaneous Earth Fault Element - Siemens 7SR17 Rho Manual

Chapter 1) 7SR17 Rho Description Of Operation
3.5.2

Derived Earth Fault Protection (50N)

Each instantaneous element has independent settings for pick-up current 50N-n Setting and a follower time
delay 50N-n Delay. The instantaneous elements have transient free operation.
Operation of the instantaneous earth fault elements can be inhibited from:
Inhibit 50N-n
Gn 50N-n Element
Disabled
Enabled
EF In
Inhibit 50N-n
I
A
I
B
I
C
50N-n Dir Control
Non Dir
Forward
Reverse
67N Fwd
67N Rev
Figure 3-17
Page 46 of 78
A binary or virtual input
&
Gn 50N-n Setting
En
I
N
>
Dir En En
50N-n VTS
Action
Non Dir
Inhibit
&
1
&
Logic Diagram: Derived Instantaneous Earth Fault Element
Gn 50N-n Delay
&
VT Fail
If directional elements are not present this
block is omitted and 'Dir En' signal is set TRUE.
©2014 Siemens Protection Devices Limited
General Pickup
50N-n
&
50N-n Dir En
&
1