
7SR224 Argus Description of Operation
Figure 3.3-1 Logic Diagram: Measured Directional Earth Fault Protection
3.3.2 Instantaneous Measured Earth Fault Protection (50G)
Four elements are provided e.g. giving the option of using two elements set to forward and two to reverse.
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.
For the directional elements the direction of operation can be set using
50G-n Dir. Control
setting. Directional
logic is provided independently for each 50G-n element.
Operation of the instantaneous measured earth fault elements can be inhibited from:
Inhibit 50G-n
A binary or virtual input, or function key
79 E/F Inst Trips: 50G-n
When ‘delayed’ trips only are allowed in the autoreclose sequence
(
79 E/F Prot’n Trip n
=
Delayed
).
50G-n Inrush Action: Inhibit
Operation of the current inrush detector function.
50G-n VTSAction: Inhibit
Operation of the VT Supervision function.
Figure 3.3-2 Logic Diagram: Measured Instantaneous Earth-fault Element
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Chapter 1 Page 24 of 70