ABB REQ650 User Manual

of the line breakers. The dead time selected should be long enough to ensure a high
probability of arc de-ionization and successful reclosing.
For individual line breakers, auto-reclosing equipment or functions, the auto-
reclosing open time is used to determine line “dead time”. When simultaneous
tripping and reclosing at the two line ends occurs, auto-reclosing open time is
approximately equal to the line “dead time”. If the open time and dead time differ then,
the line will be energized until the breakers at both ends have opened.
Open
Closed
Operate time
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Circuit
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Break time
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Fault duration SMBRREC open time for breaker
Fault duration
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Break timeClosing time
Operate time
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Set SMBRREC open time Reclaim time
Auto-reclosing
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IEC09000204_1_en.vsd
IEC09000204 V1 EN
Figure 86: Single-shot automatic reclosing at a permanent fault
Three-phase automatic reclosing can be performed with or without the use of a
synchrocheck, and an energizing check, such as dead line or dead busbar check.
For the individual line breakers and auto-reclosing equipment, the ”auto-reclosing
open time” expression is used. This is the dead time setting for the Auto-Recloser.
During simultaneous tripping and reclosing at the two line ends, auto-reclosing open
time is approximately equal to the line dead time. Otherwise these two times may
differ as one line end might have a slower trip than the other end which means that the
line will not be dead until both ends have opened.
If the fault is permanent, the line protection will trip again when reclosing is attempted
in order to clear the fault.
It is common to use one automatic reclosing function per line circuit-breaker (CB).
When one CB per line end is used, then there is one auto-reclosing function per line
Section 10 1MRK 505 291-UEN A
Control
198
Application manual

ABB REQ650 Specifications

General

Brand	ABB
Model	REQ650
Category	Protection Device
Language	English