Broken Conductor (46Bc) - Siemens 7SR224 Technical Manual

3.5

Broken Conductor (46BC)

I
(I /I
G
V
(V
V
(V
V
(V
(V
Figure 3-5 Broken Conductor
Voltage Inputs:
Current Inputs:
Disable: 51N, 46IT, 46DT
Map Pickup LED:
Broken Conductor uses the ratio of NPS current to PPS current to detect an open circuit conductor. These
quantities can be produced directly from many advanced test sets but with limited equipment the following
approach can be applied.
Apply 3P balanced current with normal phase rotation direction. This current will consist of PPS alone, no NPS or
ZPS.
Increase 1 phase current magnitude in isolation to produce NPS. The single phase unbalance current will contain
equal quantities of ZPS, NPS and PPS. The NPS component will be 1/3 of the unbalance current and the total
PPS component will be value of the original balanced 3P current plus 1/3 of the additional unbalance current. i.e.
as the single phase unbalance current increases, the ratio of NPS to PPS will also increase. The levels of each
sequence component current can be monitored in the Current Meters in Instruments Mode.
Note that if the relay is applied on a non-standard A-C-B networks, the positive and negative sequences are
reversed and the 3 phase test supply must be arranged to suit.
©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
4 (x4)
)
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
n/a
I (I ), I (I ), I (I ),
L1 A L2 B L3 C
46BC - Self Reset
7SR224 Argus Commissioning & Maintenance Guide
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
59N Batt
TCS
Test
(x2)
(x3)
Cap.
79
Test
Chapter 6 Page 60 of 73