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2.3
Voltage Controlled Overcurrent (51V)
I
(I
)
L1
A
I
(I
)
L2
B
I
(I
)
L3
C
I
(I
4
G
V
(V
L1
A
V
(V
L2
B
V
(V
L3
C
Voltage Inputs:
Current Inputs:
Disable:
Map Pickup LED:
Shaped Phase Overcurrent elements 51-n should be tested for pick-up and timing before this function is tested.
The General Pickup LED can be used to assess operation of this function if other functions are disabled or if the
setting allocating General Pickup is temporarily modified.
Apply nominal 3 phase balanced voltage. Apply 3 phase balanced current at a level below the normal 51-n setting
but above the effective 51V-n setting. Ensure that the thermal rating of the relay is not exceeded. Gradually
reduce the voltage until the a-b voltage is less than the Voltage setting. Pickup LED operation can be used to
confirm the Voltage setting. If the 51V-n current setting is above the continuous rating of the relay an alternative
procedure should be used, apply test current in short duration shots with applied voltage being gradually reduced
for each subsequent shot
©2017 Siemens Protection Devices Limited
37
49
(x2)
37
49
(x2)
37
49
(x2)
46
46
NPS
BC
(x2)
)
27
)
59
(x4)
27
)
59
(x4)
27
)
59
(x4)
79
Figure 2-3
Voltage Controlled Overcurrent
OC Phase
I
(I
)
L1
A
I
(I
)
L2
B
I
(I
)
L3
C
V
(V
), V
(V
L1
A
L2
B
I
(I
), I
(I
), I
L1
A
L2
B
L3
51C, 46, 37, 49, 50CBF, 79
51-n/50-n - Self Reset
7SR11 & 7SR12 Commissioning and Maintenance Guide
67/
67/
50
51V
50
51
BF
(x4)
(x4)
67/
67/
50
51V
50
51
BF
(x4)
(x4)
67/
67/
50
51V
50
51
BF
(x4)
(x4)
67/
67/
60
60
50N
51N
CTS
VTS
(x4)
(x4)
67/
67/
50BF
50G
51G
(x4)
(x4)
NOTE: The use of some
functions are mutually exclusive
Note:
Example shows
47
81
59N
Voltage Config =
(x2)
(x4)
(x2)
Van, Vbn, Vcn
Optional
), V
(V
)
L3
C
(I
),
C
7SR12
81
51c
HBL
2
81
HBL
51c
2
81
HBL
51c
2
64H
74
T/
CCS
Control Voltage
V
(V
)
12
AB
V
(V
)
23
BC
V
(V
)
31
CA
Chapter 6 Page 17 of 72
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