Siemens siprotec 7SA6 User Manual

Functions
6-777SA6 Manual
C53000-G1176-C133-1
corresponding protection function picked up. The transmitted signal may be prolonged
by T
S
(settable in address  6HQG3URORQJ), to compensate for possible
differences in the pick-up times at the two line ends. The distance protection is set in
such a way that the first zone reaches up to approximately 85 % of the line length. In
three-end lines Z1 is also set to approx. 85 % of the shorter line section, at least,
however, up to the T-point.
The overreach zone Z1B is not relevant for this signal transmission scheme, but it can
be controlled by the automatic reclosure (see also Subsection 6.12.1).
Figure 6-42 Operation scheme of the permissive underreach transfer trip method via pickup
Sequence Figure 6-43 shows the logic diagram of the permissive underreach transfer trip
scheme for one line end.
The permissive transfer trip should only trip for faults in the )RUZDUG direction.
Accordingly, the first zone Z1of the distance protection must definitely be set to
)RUZDUGin address 2SPRGH=, refer also to Subsection 6.2.4.2 under the
margin heading “Independent Zones Z1 up to Z5”.
On two terminal lines, the signal transmission may be done phase segregated. On
three end lines, the transmit signal is sent to both opposite line ends. The receive
signals are then combined with an
OR logic function. By means of the parameter /LQH
&RQILJ (address ) the device is informed whether it has one or two opposite
ends.
If at one line end there is weak or zero infeed, so that the distance protection does not
pick up, the circuit breaker can still be tripped. This “weak-infeed tripping” is referred
to in Section 6.7.
AB
Z1(A)
Z1(B)
PICKUP(A)
PICKUP(B)
Z1
PU
(B)
(B)
T
S
T1
&
≥1
trip
transm.
rec.
further
zones
Z1
PU
(A)
(A)
T
S
T1
&
≥1
trip
transm.
rec.
further
zones
PICKUP(A)
PICKUP(B)

Siemens siprotec 7SA6 Specifications

General

Brand	Siemens
Model	siprotec 7SA6
Category	Relays
Language	English