Siemens 7SR10 Argus Series, Manual

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7SR10 Description of Operation
©2018 Siemens Protection Devices Limited Chapter 1 Page 26 of 77
V
23
I
L1
V
31
2-out-of-3
logic
(fwd)
V
12
I
L3
I
L2
fwd
rev
fwd
rev
fwd
rev
2-out-of-3
logic
(rev)
67
2-Out-Of-3 Logic
67 Min. Voltage
67 Charact. Angle
L1 Fwd
L1 Rev
L3 Fwd
L2 Fwd
L3 Rev
L2 Rev
Directional
Control Signal
Figure 3-1 Logic Diagram: Directional Overcurrent Element (67)
3.1.2 Instantaneous Overcurrent Protection (50)
Two Instantaneous overcurrent elements are provided in the 7SR1002/7SR1003 relay and four elements are
provided in the 7SR1004 relay.
50-1, 50-2, (50-3 & 50-4 – 7SR1004)
Each instantaneous element (50-n) has independent settings. 50-n Setting for pick-up current and 50-n Delay
follower time delay. The instantaneous elements have transient free operation.
Where directional elements are present the direction of operation can be set using
50-n Dir. Control setting.
Directional logic is provided independently for each 50-n element, e.g. giving the option of using two elements set
to forward and two to reverse.
Operation of the instantaneous overcurrent elements can be inhibited from:
Inhibit 50-n A binary or virtual input.
79 P/F Inst Trips: 50-n When ‘delayed’ trips only are allowed in the auto-reclose sequence
( 79 P/F Prot’n Trip n = Delayed ).
50-n Inrush Action: Block
Operation of the inrush current detector function.
50-n VTS Action: Inhibit Operation of the VT Supervision function.