ABB RER620 Technical Manual page 318

Section 5
Control functions
312
Example 2
There are two separate sequences implemented with three shots. Shot 1 is implemented by
CBB1 and it is initiated with the high stage of the overcurrent protection (50P-1). Shot 1
is set as a high-speed autoreclosing with a short time delay. Shot 2 is implemented with
CBB2 and meant to be the first shot of the autoreclose sequence initiated by the low stage
of the overcurrent protection (51P) and the low stage of the non-directional ground-fault
protection (51N/G). It has the same reclose time in both situations. It is set as a high-speed
autoreclosing for corresponding faults. The third shot, which is the second shot in the
autoreclose sequence initiated by 51P or 51N/G, is set as a delayed autoreclosing and
executed after an unsuccessful high-speed autoreclosing of a corresponding sequence.
Figure 164: Autoreclose sequence with two shots with different shot settings
according to initiation signal
t Time delay of high-speed autoreclosing, here:
HSAR
t Time delay of delayed autoreclosing, here:
DAR
t Operating time for the 50P-1 protection stage to clear the fault
l>>
t or Operating time for the 51P or 51N/G protection stage to clear the fault
l> lo>
t Operating time for opening the circuit breaker
CB_O
t Operating time for closing the circuit breaker
CB_C
In this case, the number of needed CBBs is three, that is, the first shot's reclosing time
depends on the initiation signal. The CBB sequence is as follows:
1MAC309294-MB F
First reclose time
Second reclose time
RER620
Technical Manual