7SR11 & 7SR12 Description Of Operation
©2017 Siemens Protection Devices Limited Chapter 1 Page 37 of 88
3.2.2
I
NSTANTANEOUS
D
ERIVED
E
ARTH
F
AULT
P
ROTECTION
(50N)
Two instantaneous derived earth fault elements are provided in the 7SR11 relay and four elements are provided
in the 7SR12 relay.
50N-1, 50N-2, (50N-3 & 50N-4 – 7SR12)
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 (7SR1205 & 7SR1206).
50N-n
>
c
50N-n
Setting
If directional elements are not present this block is
omitted and the '50N-n Dir En' signal is set TRUE.
Forward
Reverse
50N-n Dir
Non-Dir
≥
1
&
&
50N-n Dir En
67N Fwd
67N Rev
50N-n Delay
50N-n VTS Action
Off
Non Dir
Inhibit
VT Fail
&
&
&
≥
1
IL1
IL2
IL3
I
N
Inhibit 50N-n
&
50N-n Element
Enabled
Disabled
81HBL2
50N-n Inrush
Action
Off
Inhibit
&
50N-n Dir En
General Pickup
&
79 P/F Inst Trips
= 50N-n
79 P/F Prot’n Trip n
= Delayed
AUTORECLOSE
Figure 3-6 Logic Diagram: Derived Instantaneous Earth Fault Element
3.2.3
T
IME
D
ELAYED
D
ERIVED
E
ARTH
F
AULT
P
ROTECTION
(51N)
Two time delayed derived earth fault elements are provided in the 7SR11 relay and four elements are provided in
the 7SR12 relay.
51N-1, 51N-2, (51N-3 & 51N-4 – 7SR12)
51N-n Setting
sets the pick-up current level.
A number of shaped characteristics are provided. An inverse definite minimum time (IDMT) characteristic is
selected from IEC and ANSI curves using
51N-n Char
. A time multiplier is applied to the characteristic curves
using the
51N-n Time Mult
setting. Alternatively, a definite time lag delay (DTL) can be chosen using
51N-n
Char
. When definite time lag (DTL) is selected the time multiplier is not applied and the
51N-n Delay (DTL)
setting is used instead.
Summary of Contents for Argus 7SR11
Page 1: ...Energy Management 7SR11 7SR12 Argus Overcurrent Relay Reyrolle Protection Devices ...
Page 2: ......
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Page 254: ...7SR11 7SR12 Installation Guide Chapter 5 Page 2 of 32 2017 Siemens Protection Devices Limited ...
Page 358: ...7SR11 7SR12 Applications Guide Page 2 of 48 2017 Siemens Protection Devices Limited ...
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