Siemens 7SR18 Solkor - Page 336

7SR18 Commissioning & Maintenance Guide
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of
3.7 NEGATIVE PHASE SEQUENCE OVERCURRENT (46NPS)
46
BC
46
NPS
(x2)
37
(x2)
49
50
BF
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
I
4
(I
G
)
74
T/
CCS
NOTE: The use of some
functions are mutually exclusive
50
(x2)
51
(x2)
50N
(x2)
50
(x2)
50
(x2)
51
(x2)
51
(x2)
51N
(x2)
50G
(x2)
51G
(x2)
60
CTS
50BF
51c
51c
51c
Figure 3.7-1 Negative Phase Sequence Overcurrent
Current Inputs: I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
),
Disable: 51, 51C, 37, 49, 50CBF, 60CTS, 46BC
Map Pickup LED: 46IT/46DT - Self Reset
Where two NPS elements are being used with different settings, it is convenient to test the elements with the
highest settings first. The elements with lower settings can then be tested without disabling the lower settings.
The Thermal withstand limitations of the current inputs, stated in the Performance Specification should always be
observed throughout testing.
NPS Overcurrent can be tested using a normal 3P balanced source. Two phase current connections should be
reversed so that the applied balanced 3P current is Negative Phase Sequence.