Out Of 3 Logic; Phase Overcurrent (67/50,67/51); Figure 2-2 Phase Overcurrent - Siemens 7SR224 Manual

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
No 50/51-n Operation
2.2

Phase Overcurrent (67/50,67/51)

I
(I /I
G
V
(V
V
(V
V
(V
(V
Figure 2-2 Phase Overcurrent
Voltage Inputs:
Current Inputs:
Disable: 51V, 51C, 46, 49, 50CBF, 79
Map Pickup LED:
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.
©2010 Siemens Protection Devices Limited
37 50
49
(x2) BF
I
L1
(I )
A
37 50
49
(x2) BF
I
L2
(I )
B
37 50
49
(x2) BF
I
L3
(I )
C
46
46 60
NPS
BC CTS
(x2)
67/
64
50G
H
(x4)
4
)
SEF
NOTE: The use of some
functions are mutually exclusive
27
27S
L1
59
) 59S
A
(x4)
27
27S
L2
59
) 59S
B
(x4)
27
27S
L3
59
) 59S
C
(x4)
V 27
4
) 59
X
V (V ), V (V ), V
L1 A L2 B L3
I (I ), I (I ), I (I ),
L1 A L2 B L3 C
51-n/50-n - Self Reset
7SR224 Argus Commissioning & Maintenance Guide
2 phase current
50/51-n operation
7SR224
67/ 67/ 81
51V 50 51 HBL
(x4) (x4) 2
67/ 67/ 81
51V 50 51 HBL
(x4) (x4) 2
67/ 67/ 81
51V 50 51 HBL
(x4) (x4) 2
60
VTS
67/ 67/ 67/
51G 50S 51S
(x4) (x4) (x4)
Note:
Example shows
Voltage Config =
47 81 Van, Vbn, Vcn
(x2)
(x4)
74
Batt
59N
TCS
(x2) Test
(x3)
Cap.
79
Test
(V ) for directional elements.
C
Chapter 6 Page 16 of 73