Figure 3-14 Logic Diagram: 7Sr10 Sef Time Delayed Element (51Sef); Figure 3-15 Logic Diagram: 7Sr10 Sef Time Delayed Element (51Sef) - Siemens 7SR10 Argus Series Manual

The 51SEF-n Reset setting can apply a definite time delayed reset, or when configured as an IEC or ANSI
characteristic an IEC/ANSI (DECAYING) reset. The reset mode is significant where the characteristic has reset
before issuing a trip output – see 'Applications Guide'.
A minimum operate time for the characteristic can be set using 51SEF-n Min. Operate Time setting.
A fixed additional operate time can be added to the characteristic using 51SEF-n Follower DTL setting.
Where directional elements are present the direction of operation can be set using 51SEF-n Dir. Control setting.
Directional logic is provided independently for each 51SEF-n element e.g. giving the option of using two elements
set to forward and two to reverse.
Operation of the time delayed earth fault elements can be inhibited from:
Inhibit 51SEF-n
79 SEF Inst Trips: 51SEF-n
51SEF-n VTSAction: Inhibit
Directional elements will not operate unless the zero sequence voltage (V
Voltage setting i.e. the residual voltage is greater than 3 times this setting and the phase is in the
Forward/Reverse operating range.
51SEF-n Element
Disabled
Enabled
AUTORECLOSE
Inhibit 51SEF-n
79 P/F Inst Trips
= 51SEF-n
&
79 P/F Prot'n Trip n
= Delayed

Figure 3-14 Logic Diagram: 7SR10 SEF Time Delayed Element (51SEF)

51SEF-n Dir.
Control
Non-Dir
Forward
Reverse
67SEF Fwd
67SEF Rev

Figure 3-15 Logic Diagram: 7SR10 SEF Time Delayed Element (51SEF)

©2018 Siemens Protection Devices Limited
A binary or virtual input
When 'delayed' trips only are allowed in the auto-reclose sequence
(79 SEF Prot'n Trip n = Delayed).
Operation of the VT Supervision function.
51SEF-n Setting
51SEF-n Charact
51SEF-n Time Mult
51SEF-n Delay (DTL)
51SEF-n Min Operate Time
51SEF-n Follower DTL
&
51SEF-n Reset
c
IL
4
(I )
SEF
51SEF-n VTS Action
Off
Non-Dir
Inhibit
VT Fail
&
≥1
&
7SR10 Description of Operation
) is above the 67SEF Minimum
0
General Pickup
Pickup
51SEF-n
trip
& &
≥1
&
Chapter 1 Page 39 of 77
51SEF-n Dir En