Siemens siprotec 7SA6 User Manual

Functions
6-206 7SA6 Manual
C53000-G1176-C156-2
A few seconds are generally sufficient. In regions with frequent storms and thunder-
storms a shorter reclaim time is advisable to reduce the risk of a final trip due to re-
peated lightning strikes or cable flashovers.
A long reclaim time must be selected in conjunction with multiple reclosure (see
above) if the circuit-breaker can not be monitored (e.g. due to missing auxiliary con-
tacts and CB–ready–information). Then the reclaim time must be longer than the re-
covery time of the circuit-breaker.
The blocking duration following Manual–Close–detection
T-BLOCK MC (address
3404) must guarantee safe switching on and off of the circuit-breaker (0.5 s to 1 s). If
a fault is detected by a protection function within this time after detected closing of the
circuit-breaker, no reclosure takes place and a final three-pole trip is issued. If this is
not desired, address
3404 is set to 0.
The options for the treatment of evolving faults are described in Section 6.14.1 under
the Sub-section “Handling of Sequential Faults” (page 195). The treatment of evolving
faults is not necessary on line ends where the adaptive dead time is applied (address
133 Auto Reclose = Adaptive Dead Time (ADT), Section 5.1). The addresses
3406 and 3407 are then of no consequence and therefore not accessible.
The detection of an evolving fault can be defined under address
3406 EV. FLT.
RECOG. with PICKUP
means that, during a dead time, every fault detection (pickup)
by a protection function will be interpreted as an evolving fault. With
EV. FLT. REC-
OG. with TRIP
a fault during a dead time is only interpreted as an evolving fault if it
has led to a
trip command by a protection function. This may also include trip com-
mands which are coupled in from external via a binary input or which have been trans-
mitted from an opposite end of the protected object. If an external protection device
operates with the automatic reclosure, evolving fault detection with pickup requires the
connection of a start signal from the external device to the 7SA6; otherwise an evolv-
ing fault can only be detected with the external trip command even if
with PICKUP
was set here.
The reaction in response to evolving faults can be selected under address
3407. EV.
FLT. MODE blocks AR
means that no reclosure takes place after detection of an
evolving fault. This is always useful when only single-pole reclosure is to take place or
when stability problems are expected due to the subsequent three-pole dead time. If
a three-pole reclose cycle is to be initiated by tripping of the evolving fault, set
EV.
FLT. MODE
= starts 3p AR. In this case a separately adjustable three-pole dead time
is started with the three-pole trip command due to the evolving fault. This is only useful
if three-pole reclosure is also permitted.
Address
3408 T-Start MONITOR monitors the reaction of the circuit-breaker after a
trip command. If the CB has not opened during this time (from the beginning of the trip
command), the automatic reclosure is blocked dynamically. The criterion for circuit
breaker opening is the position of the circuit-breaker auxiliary contact or the disap-
pearance of the trip command. If a circuit-breaker failure protection (internal or exter-
nal) is used on the feeder, this time should be shorter than the delay time of the circuit-
breaker failure protection so that no reclosure takes place if the circuit-breaker fails.
If the reclosure command is transmitted to the opposite end, this transmission can be
delayed by the time setting in address
3410 T RemoteClose. This transmission is
only possible if the device operates with adaptive dead time at the remote end
(ad-
dress
133 Auto Reclose = Adaptive Dead Time (ADT) at remote end). This
parameter is otherwise irrelevant. On the one hand, this delay serves to prevent the
remote end device from reclosing unnecessarily when local reclosure is unsuccessful.
On the other hand it should be noted that the line is not available for energy transport
until the remote end has also closed. This delay must therefore be added to the dead
time for consideration of the network stability.

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English