7PG2113/4/5/6 Commissioning & Maintenance
©2012 Siemens Protection Devices Limited
Chapter 6 Page 66 of 77
3.3.2.1 Element
Blocking
The CT Supervision function can be blocked by Binary Input Inhibit. This functionality should be checked.
Element BI
Inhibits
60CTS
Table 3.3-3
60CTS Element Blocking
3.4
Broken Conductor (46BC)
Figure 3.4-1 Broken Conductor
Voltage Inputs:
n/a
Current Inputs:
I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
)
Disable:
51N,
46IT,
46DT
Map Pickup LED:
46BC - Self Reset
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
.