7SR210 & 7SR220 Commissioning & Maintenance Guide
© 2013 Siemens Protection Devices Limited Page 35 of 82
2.5 Sensitive Earth fault (67/50S,67/51S)
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
(x4)
67/
51
(x4)
67/
50N
(x4)
67/
50
(x4)
67/
50
(x4)
67/
51
(x4)
67/
51
(x4)
67/
51N
(x4)
67/
50G
(x4)
67/
51G
(x4)
67/
50S
(x4)
67/
51S
(x4)
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
50
AFD
50
AFD
50
AFD
51c
51c
51c
Figure 2.5-1 Sensitive Earth Fault
Voltage Inputs: V
L1
(V
A
), V
L2
(V
B
), V
L3
(V
C
) for directional elements
Current Inputs: I
5
(I
SEF
)
Disable: 64H, 50BF, 79
Map Pickup LED: 51SEF-n/50SEF-n - Self Reset
Other protection functions may overlap with these functions during testing; it may be useful to disable some
functions to avoid ambiguity. Derived EF, Measured EF, Sensitive EF & Restricted EF protections can be
Enabled/Disabled individually or as groups in the ‘Function Config’ menu.
Sensitive EF elements can be separated from Derived EF and Measured EF by secondary injection of current
through the I
5
input circuit only.
If any of these elements are defined as directional the correct voltage phase direction will be required to produce
an operation of those elements.
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