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2.10 Restricted Earth fault (64H)
I
L1
I
L2
I
L3
Voltage Inputs:
Current Inputs:
Disable:
Map Pickup LED:
The setting resistance should be measured and the value compared to that specified in the settings data. Both
values should be recorded.
Settings Data Resistor Value
The high value of setting resistance R will often interfere with secondary current injection when using a digital test
set. It is normal practice in these cases to short out the series resistor to allow testing, the shorting link should be
removed after testing.
Since the DTL setting is generally small the pick-up setting can be tested by gradually increasing current until
element operates. The relay should be disconnected from the current transformers for this test.
Apply 2x setting current if possible and record operating time
Phase
Is
DTL
(Amps)
(sec)
REF
©2017 Siemens Protection Devices Limited
37
(x2)
(I
)
A
37
(x2)
(I
)
B
37
(x2)
(I
)
C
46
BC
I
(I
)
4
G
27
V
(V
)
59
L1
A
(x4)
27
V
(V
)
59
L2
B
(x4)
27
V
(V
)
59
L3
C
(x4)
Figure 2-11
n/a
I
(I
)
4
REF
51SEF, 50SEF, 79
64H - Self Reset
P.U. Current
Amps
7SR11 & 7SR12 Commissioning and Maintenance Guide
67/
67/
50
49
51V
50
51
BF
(x4)
(x4)
67/
67/
50
49
51V
50
51
BF
(x4)
(x4)
67/
67/
50
49
51V
50
51
BF
(x4)
(x4)
46
67/
67/
60
60
NPS
50N
51N
CTS
VTS
(x2)
(x4)
(x4)
67/
67/
50BF
50
51
SEF
SEF
NOTE: The use of some
functions are mutually exclusive
47
81
59N
(x2)
(x4)
(x2)
Optional
79
Restricted Earth Fault
Measured
Tolerance
Operate Time
7SR12
81
HBL
51c
2
81
HBL
51c
2
81
HBL
51c
2
64H
Note:
Example shows
Voltage Config =
Van, Vbn, Vcn
74
T/
CCS
Tolerance
2 x Is
Chapter 6 Page 37 of 72
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