Instantaneous Overcurrent Protection (50); Figure 3-1 Logic Diagram: Directional Overcurrent Element (67) - Siemens 7SR10 Argus Series Manual

V
23
I
L1
V
31
I
L2
V
12
I
L3
Figure 3-1
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.
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
79 P/F Inst Trips: 50-n
50-n Inrush Action: Block
50-n VTS Action: Inhibit
©2018 Siemens Protection Devices Limited
67
67 Charact. Angle
67 Min. Voltage
fwd
rev
fwd
rev
fwd
rev
Logic Diagram: Directional Overcurrent Element (67)
50-1, 50-2, (50-3 & 50-4 – 7SR1004)
A binary or virtual input.
When 'delayed' trips only are allowed in the auto-reclose sequence
(79 P/F Prot'n Trip n = Delayed).
Operation of the inrush current detector function.
Operation of the VT Supervision function.
7SR10 Description of Operation
Directional
2-Out-Of-3 Logic
Control Signal
L1 Fwd
2-out-of-3
logic
L2 Fwd
(fwd)
L3 Fwd
L1 Rev
2-out-of-3
logic
L2 Rev
(rev)
L3 Rev
Chapter 1 Page 26 of 77