Siemens 7SR224 - Voltage Controlled Overcurrent (51 V)

7SR224 Argus Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited Chapter 6 Page 19 of 73
2.3 Voltage Controlled Overcurrent (51V)
Figure 2-3 Voltage Controlled Overcurrent
Voltage Inputs: V
L1
(V
A
), V
L2
(V
B
), V
L3
(V
C
)
Current Inputs: I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
),
Disable: 51C, 46, 37, 49, 50CBF, 79
Map Pickup LED: 51-n/50-n - Self Reset
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
Apply nominal 3 phase balanced voltage. Reduce the voltage such that the a-b voltage is 110% of the Voltage
setting
Gradually increase the a-b phase current or balanced 3P current until Pickup LED operates. Confirm result of
Phase O/C test above.
Reduce the applied voltage to a level such that V
12
(V
AB
) phase-phase voltage is less than 90% of the setting.
Gradually increase the I
12
(I
AB
) phase-phase current until Pickup LED operates.
Note that these elements may be set as directional. If this is the case, the phase angle of the current must be set
with respect to the voltage to produce operation of the elements.
OC Phase Control Voltage
I
L1
(I
A
) V
12
(V
AB
)
I
L2
(I
B
) V
23
(V
BC
)
I
L3
(I
C
) V
31
(V
CA
)
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