Siemens 7SR224 - Out of 3 Logic; Phase Overcurrent (67;50,67;51)

7SR224 Argus Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited Chapter 6 Page 16 of 73
2.1.1 2 out of 3 logic
Ensure that at least 1 Phase Overcurrent element is set to Directional. Apply balanced nominal voltage. Apply
current at a level above on phase A only at the characteristic angle for forward operation, normally 45º lagging.
Ensure no Directional Phase Overcurrent element operation occurs. Note that non-directional Phase Overcurrent
and Non-direction Earth Fault elements may operate unless disabled.
Repeat the test with Phase A current as above but also with equal current in the B phase at 180º to that in the A
phase.
1 phase current 2 phase current
No 50/51-n Operation 50/51-n operation
2.2 Phase Overcurrent (67/50,67/51)
7SR224
46
BC
46
NPS
(x2)
37
(x2)
49
50
BF
51V
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
51V
I
L2
(I
B
)
81
HBL
2
37
(x2)
49
50
BF
51V
I
L3
(I
C
)
81
HBL
2
60
CTS
60
VTS
I
4
(I
G
/I
SEF
)
74
TCS
(x3)
NOTE: The use of some
functions are mutually exclusive
67/
50
(x4)
67/
51
(x4)
67/
50
(x4)
67/
50
(x4)
67/
51
(x4)
67/
51
(x4)
64
H
27
59
27
59
(x4)
27
59
(x4)
27
59
(x4)
47
(x2)
79
59N
(x2)
Note:
Example shows
Voltage Config =
Van, Vbn, Vcn
81
(x4)
67/
50G
(x4)
67/
51G
(x4)
67/
50S
(x4)
67/
51S
(x4)
27S
59S
27S
59S
27S
59S
Batt
Test
Cap.
Test
Figure 2-2 Phase Overcurrent
Voltage Inputs: V
L1
(V
A
), V
L2
(V
B
), V
L3
(V
C
) for directional elements.
Current Inputs: I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
),
Disable: 51V, 51C, 46, 49, 50CBF, 79
Map Pickup LED: 51-n/50-n - Self Reset
Other protection functions may overlap with these functions during testing, it may be useful to disable some
functions to avoid ambiguity. It should be particularly noted that if the function is enabled, the 51C Cold Load
settings may modify the normal 50-n and 51-n settings if the CB is open during testing.
Voltage inputs may not be required for this function if the Phase Overcurrent functions are not directional but it
may be advantageous to apply balanced 3 phase nominal rated voltage to the VT inputs during testing to avoid
inadvertent operation of other functions. Particular care should be taken when testing overcurrent functions that
the thermal rating of the current inputs is not exceeded.