Siemens 7SR51 - Supervision Functions; 50 BF Circuit-Breaker Failure Protection - 3 Pole; 60 CTS CT Supervision

Supervision Functions
50BF Circuit-Breaker Failure Protection – 3 Pole
The circuit‑breaker fail protection time delays are initiated either from:
•
A binary output mapped as Trip Contact in the Configuration > Binary Inputs > Input
Matrix menu, or
•
A binary input mapped as 50BF Ext Trip in the Configuration > Binary Inputs > Input
Matrix menu. Or
•
A binary input mapped as 50BF Mech Trip in the Configuration > Binary Inputs > 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
energized 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 CT4 and using the 50BF-I4 Setting.
50BF Setting (⋅ I
rated
) Test Current 50BF-1 Delay 50BF-2 Delay
(110 %)
(90 %) No Operation No Operation
50BF CB Faulty Operation No Delay Operation No Delay
50BF-I4 Setting (⋅ I
rated
) Test Current 50BF-1 Delay 50BF-2 Delay
(110 %)
(90 %) No Operation No Operation
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 Configuration > Binary Inputs
> Input Matrix menu.
Initiate this binary input and simulate the circuit‑breaker remaining closed by ensuring the CB Closed binary
input is energized and ensure operation of the 50BF-1 and 50BF-2 outputs after their programmed delays.
50BF Mech Trip
50BF-1 Delay 50BF-2 Delay
CB Closed
CB Open No Operation No Operation
Element Blocking
The CB Fail function can be blocked by Binary Input Inhibit. This functionality should be checked.
Element
BI Inhibits
50BF
60CTS CT Supervision
60CTS-I CT Supervision – Current Reference
Apply 3 Phase balanced current to the relay, reduce the current in any 1 or 2 phases to a level below 60CTS-I
setting. Measure the delay to operation.
9.10
9.10.1
9.10.2
Functional Tests
9.10 Supervision Functions
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 497
C53000-G7040-C014-1, Edition 11.2019