Siemens siprotec 7SD5 User Manual page 180

2 Functions
Sequence
Figure 2-70 Logic diagram of the permissive underreach transfer trip (PUTT) using Z1B (one line end)
The permissive transfer trip should only send for faults in the „Forward" direction. Ac-
cordingly, the first zone Z1 of the distance protection must definitely be set to Forward
in address 1601 Op. mode Z1, refer also to Section 2.5.1 under the margin heading
„Independent Zones Z1 up to Z5".
On two terminal lines, the signal transmission may be phase segregated. Send and
receive circuits in this case are built up for each phase. On three terminal lines, the
transmit signal is sent to both opposite line ends. The receive signals are then com-
bined with an OR logic function.
With the parameter Type of Line (address 2102) the device is informed as to
whether it has one or two opposite line ends.
During disturbance of the signal transmission path, the overreaching zone Z1B may
be activated by an automatic reclosure (internal or external) via the binary input
„>Enable ARzones".
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7SD5 Manual
C53000-G1176-C169-1