Siemens 7SR242 Duobias - 2.6 Negative Phase Sequence Overcurrent (46 NPS)

7SR242 Duobias Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited Chapter 6 Page 31 of 57
2.6 Negative Phase Sequence Overcurrent (46NPS)
Figure 2-8 Negative Phase Sequence Overcurrent
Voltage Inputs: n/a
Current Inputs: W1-I
L1
(I
A
), W1-I
L2
(I
B
), W1-I
L3
(I
C
), or W2-I
L1
(I
A
), W2-I
L2
(I
B
), W2-I
L3
(I
C
),
Disable: 50, 51, 50BF, 87BD
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.
These elements can be allocated to W1 or W2 current inputs by relay settings, ensure that current is injected on
the correct input.
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.