Siemens Argus 7SR21 - Page 585

7SR210 & 7SR220 Commissioning & Maintenance Guide
© 2013 Siemens Protection Devices Limited Page 73 of 82
3.5 Load Blinder (21)
7SR22
46
BC
46
NPS
(x2)
37
(x2)
49
50
BF
V
L1
(V
A
)
V
L2
(V
B
)
V
L3
(V
C
)
V
4
(V
X
)
I
L1
(I
A
)
81
HBL
2
37
(x2)
49
50
BF
I
L2
(I
B
)
81
HBL
2
37
(x2)
49
50
BF
I
L3
(I
C
)
81
HBL
2
60
CTS
I
4
(I
G
)
I
5
(I
SEF
)
74
TCS
NOTE: The use of some
functions are mutually exclusive
67 / 50 /
51( x 4 )
67/
50 /51N
( x 4 )
67/
50/51G
( x 4 )
67/
50/51S
( x 4 )
64
H
27
59
27
59
(x4)
27
59
(x4)
27
59
(x4)
47
(x2)
81
(x6)
79
Optional
59N
(x2)
81
HBL
2N
60
VTS
51V
51V
51V
37G
(x2)
37S
(x2)
51c
60
CTS-
I
60
CTS-
I
60
CTS-
I
37
50
BF
37
50
BF
25
21
LB
21
LB
21
LB
51c
51c
51c
50
AFD
50
AFD
50
AFD
67 / 50 /
51( x 4 )
67 / 50 /
51( x 4 )
Figure 3.5-1 Load Blinder (21)
Voltage Inputs: V
L1
(V
A
), V
L2
(V
B
), V
L3
(V
C
)
Current Inputs: I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
),
Disable: 51-n, 51V, 51c, 46, 49, 50BF, 79
Map Pickup LED: 21LB-3P, 21LB-1P - Self Reset
Load Blinders are designed to block Overcurrent elements from tripping in heavy load conditions.
User settings 21LB-3P Angle and 21LB-3P Impedance allow user to define the Blinder region depending on the
networks or specifically a line’s loading and fault limits.
The calculated impedance can be: -
· In Blinder Region in which case the Load Blinder FWD or REV is active depending on if the impedance is
in the 1
st
or 4
th
and/or 2
nd
or 3
rd
quadrant of the R-X plot respectively.
· In operate region in which case there is no active Load Blinder block and the Overcurrent element
operates depending on additional factors.
· A 5 degree Hysteresis is allowed between operate and block zone.