Application - ABB REC670 Applications Manual

Section 14
Control
14.2.2
324

Application

Automatic reclosing is a well-established method for the restoration of service in a
power system after a transient line fault. The majority of line faults are flashovers,
which are transient by nature. When the power line is switched off by the operation of
line protection and line breakers, the arc de-ionizes and recovers its ability to withstand
voltage at a somewhat variable rate. Thus, a certain dead time with a de-energized line
is necessary. Line service can then be resumed by automatic reclosing 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, the required circuit breaker
dead time is used to determine the "dead time" setting value. When simultaneous
tripping and reclosing at the two line ends occurs, line dead time is approximately
equal to the auto recloser "dead time". If the auto reclosing dead time and line "dead
time" differ then, the line will be energized until the breakers at both ends have opened.
Line
protection
Operate time
Closed
Circuit
breaker
Open
Break time
Fault duration
Auto-reclosing
function
ANSI04000146 V1 EN-US
Figure 113: Single-shot automatic reclosing at a permanent fault
Operate
time
Closing time
AR open time for breaker
Set AR open time
1MRK 511 401-UUS A
Break time
Fault duration
Reset time
en04000146_ansi.vsd
Bay control REC670 2.2 ANSI
Application manual
M12391-3 v8