ABB REQ650 User Manual

It is often required that the total fault clearance time shall be less than a given critical
time. This time is often dependent of the ability to maintain transient stability in case
of a fault close to a power plant.
Time
The fault
occurs
Protection
operate time
Trip and Start
CCRBRF
Normal t
cbopen
Margin
Retrip delay t1 t
cbopen
after re-trip
t
BFPreset
Minimum back-up trip delay t2
Critical fault clearance time for stability
IEC05000479_2_en.vsd
IEC05000479 V2 EN
Figure 66: Time sequence
6.10 Breaker failure protection phase segregated
activation and output CSPRBRF
6.10.1 Identification
Function description
IEC 61850 identification IEC 60617 identification ANSI/IEEE C37.2 device
number
Breaker failure
protection, phase
segregated activation
and output
CSPRBRF
3I>BF
SYMBOL-U V1 EN
50BF
6.10.2 Application
In the design of the fault clearance system the N-1 criterion is often used. This means
that a fault needs to be cleared even if any component in the fault clearance system is
faulty. One necessary component in the fault clearance system is the circuit breaker.
Section 6 1MRK 505 291-UEN A
Current protection
136
Application manual

ABB REQ650 Specifications

General

Brand	ABB
Model	REQ650
Category	Protection Device
Language	English