Figure 3-9 Logic Diagram: Measured Instantaneous Earth-Fault Element - Siemens 7SR12 Argus Manual

7SR11 & 7SR12 Description Of Operation
3.3.2 I
NSTANTANEOUS
Two instantaneous derived earth fault elements are provided in the 7SR11 relay and four elements are provided
in the 7SR12 relay.
Each instantaneous element has independent settings for pick-up current 50G-n Setting and a follower time
delay 50G-n Delay. The instantaneous elements have transient free operation.
Where directional elements are present the direction of operation can be set using 50G-n Dir. Control setting.
Directional logic is provided independently for each 50G-n element e.g. giving the option of using two elements
set to forward and two to reverse.
Operation of the instantaneous measured earth fault elements can be inhibited from:
Inhibit 50G-n
79 E/F Inst Trips: 50G-n
50-n Inrush Action: Block
50G-n VTSAction: Inhibit
50G-n Inrush
Action
Off
Inhibit
&
81HBL2
AUTORECLOSE
79 P/F Inst Trips
= 50G-n
&
79 P/F Prot'n Trip n
= Delayed
50G-n Dir.
Control
Non-Dir
Forward
Reverse
67G Fwd
67G Rev

Figure 3-9 Logic Diagram: Measured Instantaneous Earth-fault Element

Chapter 1 Page 40 of 88
M E
EASURED ARTH
50G-1, 50G-2, (50G-3 & 50G-4 – 7SR12)
A binary or virtual input.
When 'delayed' trips only are allowed in the auto-reclose sequence
(79 E/F Prot'n Trip n = Delayed).
Operation of the inrush current detector function.
Operation of the VT Supervision function (7SR1205 & 7SR1206).
50G-n Element
Disabled
Enabled
&
Inhibit 50G-n
50G-n Dir En
51G/50G Measurement
IG
&
&
F P
AULT ROTECTION
50G-n Setting
c
>
50G-n VTS Action
Off
Non Dir
Inhibit
&
VT Fail
≥1
&
©2017 Siemens Protection Devices Limited
(50G)
General Pickup
50G-n Delay
50G-n
&
≥1
50G-n Dir En