7SR224 Argus Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited
Chapter 6 Page 53 of 73
Section 3: Supervision Functions
3.1
CB Fail (50BF)
Figure 3-1
CB Fail
Voltage Inputs:
n/a
Current Inputs:
I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
),
Disable:
Map Pickup LED:
50BF-n - Self Reset
The circuit breaker fail protection time delays are initiated either from:
A binary output mapped as
Trip Contact
in the OUTPUT CONFIG>BINARY OUTPUT CONFIG menu,
or
A binary input mapped as
50BF Ext Trip
in the INPUT CONFIG>INPUT MATRIX menu.
Apply a trip condition by injection of current to cause operation of a suitable protection element. Allow current to
continue after the trip at a level of 110% of the
50BF Setting
current level on any phase. Measure the time for
operation of operation of
50BF-1 Delay
and
50BF-2 Delay.
Repeat the sequence with current at 90% of the
50BF
Setting
current level after the element trip and check for no CB Fail operation.
50BF Setting (xIn)
Test Current
50BF-1 Delay……………
50BF-2 Delay……………….
(110%)………….
(90%)…………...
No Operation
□
No Operation
□