Siemens siprotec 7SA6 User Manual page 355

Sequence of a
Single-pole
Reclose Cycle
Sequence of a
Single and
Three-pole
Reclose Cycle
7SA6 Manual
C53000-G1176-C133-1
The sequence described above applies to a single reclosure cycle. In the 7SA6
multiple reclosure (up to 8 cycles) is also possible (see below).
Single-pole reclose cycles are only possible with the appropriate device version and if
this was selected during the configuration of the protection functions (address ,
see also section 5.1). Of course, the circuit-breaker must also be suitable for single-
pole tripping.
If the automatic reclosure function is ready, the short-circuit protection trips single pole
for all single-phase faults inside the stage valid for reclosure. It can also be selected
(address $ 7ULSSK)OW, see also section 6.1.3), by setting, that single-pole
tripping takes place for two-phase faults without earth. Single-pole tripping is of course
only possible with short-circuit protection functions that can determine the faulty
phase.
If only single-pole reclosure is selected then the short-circuit protection issues a final
three-pole trip with the stage that is valid without reclosure. Every three-pole trip is
final. The automatic reclosure is blocked dynamically (see also above under subtitle
"Reclose Block", page 6-170).
The automatic reclosure function is started following a single-pole trip. The
(adjustable) dead time for the single-pole reclose cycles starts with reset of the trip
command or opening of the circuit-breaker pole (auxiliary contact criterion). The
circuit-breaker receives a close command after the dead time. At the same time the
(adjustable) reclaim time is started. If the reclosure is blocked during the dead time
following a single-pole trip, optional immediate three-pole tripping can take place
(Forced Three-pole Trip, page 6-186).
If the fault has been cleared (successful reclosure), the reclaim time runs out and all
functions return to their quiescent state. The system fault has ended.
If the fault is not cleared (unsuccessful reclosure), the short-circuit protection issues a
final trip with the protection stage that is valid without reclosure. Any fault during the
reclaim time also leads to a final trip.
After unsuccessful reclosure (final tripping) the automatic reclosure function is blocked
dynamically (see also page 6-170, "Reclose Block")
The sequence described above applies to single reclose cycles. In the 7SA6 multiple
reclosure (up to 8 cycles) is also possible (see below).
This operating mode is only possible with the appropriate device version and if this
was selected during configuration of the protection functions (address , see also
section 5.1). Of course, the circuit-breaker must also be suitable for single-pole
tripping.
If the automatic reclosure function is ready, the short-circuit protection trips single-
pole for single-phase faults and three-pole for multi-phase faults. Under 3RZHU
6\VWHP 'DWD  36\VWHP 'DWD  (address , see also Section 6.1.3) it
can also be selected that single-pole tripping takes place for two-phase faults without
earth. Single-pole tripping is of course only possible with short-circuit protection
functions that can determine the faulty phase. The valid protection stage valid for
reclosure ready state applies for all fault types.
The automatic reclosure function is started at the instant of a trip. Depending on the
type of fault the (adjustable) dead time for the single-pole reclose cycle or the
(separately adjustable) dead time for the three-pole reclose cycle starts following the
reset of the trip command or opening of the circuit-breaker (pole). After expiry of the
dead time the circuit-breaker receives a close command. At the same time the
Functions
6-173