Siemens siprotec 7SA522 User Manual

2 Functions
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7SA522 Manual
C53000-G1176-C155-3
(adjustable) reclaim time is started. If the reclosure is blocked during the dead time fol-
lowing a single-pole trip, immediate three-pole tripping can take place as an option
(forced three-pole coupling).
If the fault is cleared (successful reclosure), the reclaim time expires and all functions
return to their quiescent state. The fault is cleared.
If the fault is not cleared (unsuccessful reclosure), the short-circuit protection issues a
final trip with the protection stage that is valid/selected without reclosure. All faults
during the reclaim time also lead to the issue of a final three-pole trip.
After unsuccessful reclosure (final tripping), the automatic reclosure is blocked dy-
namically (see also margin heading “ Reclose Block”, above).
The sequence above applies for single reclosure cycles. In 7SA522 multiple reclosure
(up to 8 cycles) is also possible (see below).
Sequence of a
Single and Three-
Pole Reclose Cycle
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 2.1.1.2). 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 the general
settings (address  7ULSSK)OW, see also Section 2.1.5.1) it can also be select-
ed 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 deter-
mine the faulty phase. The valid protection stage selected for reclosure ready state
applies for all fault types.
The automatic reclosure function is started in the event of a trip. Depending on the
type of fault the (adjustable) dead time for the single-pole reclose cycle or the (sepa-
rately 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 (adjustable)
reclaim time is started. If the reclosure is blocked during the dead time following a
single-pole trip, immediate three-pole tripping can take place as an option (forced
three-pole coupling).
If the fault is cleared (successful reclosure), the reclaim time expires and all functions
return to their quiescent state. The fault is cleared.
If the fault is not cleared (unsuccessful reclosure), the short-circuit protection initiates
a final three-pole trip with the protection stage that is valid/selected when reclosure is
not ready. All faults during the reclaim time also lead to the issue of a final three-pole
trip.
After unsuccessful reclosure (final tripping), the automatic reclosure is blocked dy-
namically (see also margin heading “Reclose Block”, above).
The sequence above applies for single reclosure cycles. In 7SA522 multiple reclosure
(up to 8 cycles) is also possible (see below).
Multi-shot
Reclosing
If a short-circuit still exists after a reclosure attempt, further reclosure attempts can be
made. Up to 8 reclosure attempts are possible with the automatic reclosure function
integrated in the 7SA522.
The first four reclosure cycles are independent of each other. Each one has separate
action and dead times, can operate single or three pole and can be blocked separately

Siemens siprotec 7SA522 Specifications

General

Brand	Siemens
Model	siprotec 7SA522
Category	Protection Device
Language	English