Siemens 7SR18 Solkor - Instantaneous Derived Earth Fault Protection (50 N); Figure 3.4.2-1 Logic Diagram: Derived Instantaneous Earth Fault Element

7SR18 Description Of Operation
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3.4.2 Instantaneous Derived Earth Fault Protection (50N)
Up to four instantaneous derived earth fault elements are provided in the relay (depending upon variant): -
50N-1, 50N-2, 50N-3 & 50N-4
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.
Where directional elements are present the direction of operation can be set using 50N-n Dir. Control setting.
Directional logic is provided independently for each 50-n element.
Operation of the instantaneous earth fault elements can be inhibited from:
Inhibit 50N-n A binary or virtual input.
79 E/F Inst Trips: 50N-n When ‘delayed’ trips only are allowed in the auto-reclose sequence
(79 E/F Prot’n Trip n = Delayed).
50-n Inrush Action: Block Operation of the inrush current detector function.
50N-n VTSAction: Inhibit Operation of the VT Supervision function
Figure 3.4.2-1 Logic Diagram: Derived Instantaneous Earth Fault Element