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These elements are operated from W1 and W2 current inputs, ensure that current is injected on the correct input
for the element being tested.
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.
Setting (xIn)
Test Current
50BF-1
(110%).............
(90%)...............
50BF CB Faulty
50BF-1-I4
(110%).............
(90%)...............
50BF CB Faulty
50BF-2
(110%).............
(90%)...............
50BF CB Faulty
50BF-2-I4
(110%).............
(90%)...............
50BF CB Faulty
If the circuit breaker can also receive a trip signal from a protection function where there is no increase in current,
this trip input should be mapped to 50BF Mech Trip in the INPUT CONFIG>INPUT MATRIX menu.
Initiate this binary input and simulate the circuit breaker remaining closed by ensuring the CB Closed binary Input
is energised and ensure operation of the 50BF-1 and 50BF-2 outputs after their programmed delays.
Mech Trip
50BF-1
CB Closed
CB Open
50BF-2
CB Closed
CB Open
3.1.1.1 Element Blocking
The CB Fail function can be blocked by Binary Input Inhibit. This functionality should be checked.
Element
BI Inhibits
50BF-1
50BF-2
©2010 Siemens Protection Devices Limited
7SR242 Duobias Commissioning & Maintenance Guide
50BF-1 Delay...............
No Operation
□
Operation No Delay □
No Operation
□
Operation No Delay □
No Operation
□
Operation No Delay □
No Operation
□
Operation No Delay □
50BF-1 Delay...............
No Operation
□
No Operation
□
NOTES
50BF-2 Delay...................
No Operation
□
Operation No Delay □
No Operation
□
Operation No Delay □
No Operation
□
Operation No Delay □
No Operation
□
Operation No Delay □
50BF-2 Delay...................
No Operation
□
No Operation
□
Chapter 6 Page 48 of 57
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