Siemens 7SR242 Duobias - Page 48

7SR242 Duobias Commissioning & Maintenance Guide
©2010 Siemens Protection Devices Limited Chapter 6 Page 48 of 57
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 Delay…………… 50BF-2 Delay……………….
(110%)………….
(90%)…………... No Operation □ No Operation □
50BF-1
50BF CB Faulty Operation No Delay □ Operation No Delay □
(110%)………….
(90%)…………... No Operation □ No Operation □
50BF-1-I4
50BF CB Faulty Operation No Delay □ Operation No Delay □
(110%)………….
(90%)…………... No Operation □ No Operation □
50BF-2
50BF CB Faulty Operation No Delay □ Operation No Delay □
(110%)………….
(90%)…………... No Operation □ No Operation □
50BF-2-I4
50BF CB Faulty Operation No Delay □ Operation No Delay □
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 Delay…………… 50BF-2 Delay……………….
CB Closed 50BF-1
CB Open No Operation □ No Operation □
CB Closed 50BF-2
CB Open No Operation □ No Operation □
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 NOTES
50BF-1
50BF-2