Application - ABB REC 561 User Manual

ABB Network Partner AB
Version 1.0-00
October 1996
Function:

1 Application

Auto-reclosing - Single- and/or
three-phase
Optional
Automatic reclosing (AR) is a well-established method to restore the serv-
ice of a power line after a transient line fault. The majority of line faults
are flashover arcs, which are transient by nature. When the power line is
switched off by operation of line protection and line breakers, the arc de-
ionizes and recovers voltage withstand at a somewhat variable rate. So a
certain line dead time is needed. But then line service can resume by the
auto-reclosing of the line breakers. Select the length of the dead time to
enable good probability of fault arc de-ionization and successful reclos-
ing.
For the individual line breakers and auto-reclosing equipment, the Auto-
reclose open time (AR open time) expression is used.
At simultaneous tripping and reclosing at the two line ends, Auto-reclose
open time equals the dead time of the line. Otherwise these two times may
differ.
In case of a permanent fault, line protection trips again at reclosing, to
clear the fault. Fig. 1 shows the operation sequence and some expressions.
The reclosing function can be selected to perform single-phase and/or
three-phase reclosing from eight single-shot to multiple-shot reclosing
programs. The three-phase auto-reclose open time can be selected from
0,2-60 s to give either High-speed auto-reclosing (HSAR), or Delayed
auto-reclosing (DAR).
Three-phase auto-reclosing can be performed with or without the use of
synchro-check and energizing check.
Single-phase tripping and single-phase reclosing is a way to limit the
effect of a single-phase line fault to system operation. Especially at the
higher voltages, the majority of line faults are of the single-phase type.
The method is of particular value to maintain system stability in systems
with limited meshing or parallel routing. It requires individual operation
of each phase of the breakers, which is most common at the higher trans-
mission voltages.
A somewhat longer dead time may be required at single-phase reclosing
compared to high-speed three-phase reclosing, due to influence on the
fault arc of the non-tripped phases.
1MRK 580 170-XEN
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