7PG2113/4/5/6 Commissioning & Maintenance
©2012 Siemens Protection Devices Limited
Chapter 6 Page 60 of 77
Section 3: Supervision Functions
3.1
CB Fail (50BF)
Figure 3.1-1 CB Fail
Voltage Inputs:
n/a
Current Inputs:
I
L1
(I
A
), I
L2
(I
B
), I
L3
(I
C
), I
L4
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.
Or
A binary input mapped as
50BF Mech 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
50BF-1 Delay
and
50BF-2 Delay.
Repeat the sequence with the 50BF CB Faulty input energised and
ensure the 50BF-1 and 50BF-2 outputs operate without delay, by-passing the timer delay settings.
Repeat the sequence with current at 90% of the
50BF Setting
current level after the element trip and check for no
CB Fail operation.
Repeat the sequence by injecting the current to I4 and using the
50BF-I4 Setting.