Current Protection: Measured Earth Fault (50G, 51G); Instantaneous Measured Earth Fault Protection (50G); Figure 3-9 Logic Diagram: Measured Instantaneous Earth-Fault Element - Siemens 7SR242 Manual

3.4

Current Protection: Measured Earth Fault (50G, 51G)

The earth current is measured directly via dedicated current analogue inputs. These optional elements utilise
either RMS or Fundamental current values as defined by the 51G/50G Measurement setting (MEASURED E/F
menu).

3.4.1 Instantaneous Measured Earth Fault Protection (50G)

Optionally two instantaneous measured earth fault elements are provided, each can be selected to either winding
1 or winding 2.
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.
Operation of the instantaneous measured earth fault elements can be inhibited from:
Inhibit 50G-n
50G-n Inrush Action: Inhibit
Figure 3-9
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A binary or virtual input.
Operation of the inrush detector function.
Logic Diagram: Measured Instantaneous Earth-fault Element
7SR242 Duobias Description Of Operation
Chapter 1 Page 29 of 52