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Functions
2.7 Teleprotection for Distance Protection (optional)
The parameter Mem.rec.sig. (address 2113) is only effective for the schemes PUTT (Z1B) with zone ac-
celeration, POTT, and UNBLOCKING. If the parameter Mem.rec.sig. (address 2113) is set to YES and an
own distance protection pickup is available in Z1B, the phase-selective release effected via the teleprotection
scheme is stored. Storing the received signal makes sense if the teleprotection scheme is used in ring net-
works as a backup protection with increased grading time.
Transient blocking
The parameters TrBlk Wait Time and TrBlk BlockTime serve the transient blocking with the permissive
(overreaching) schemes. With permissive underreach transfer trip schemes they are of no consequence.
The time TrBlk Wait Time (address 2109) is a waiting time prior to transient blocking. The transient blocking
will be activated in the permissive overreach transfer schemes only after the distance protection has not de-
tected a fault in forward direction within this time after fault detection. In the case of the blocking scheme, the
waiting time prevents transient blocking in the event that the blocking signal reception from the opposite line
end is very fast. With the setting ∞ there is no transient blocking. This parameter can only be changed in DIGSI
at Display Additional Settings.
Note
With POTT and UNBLOCKING schemes, the TrBlk Wait Time must not be set too short to prevent unwanted
activation of the transient blocking TrBlk BlockTime when the direction measurement is delayed compared
to the function pickup (signal transients). A setting of 10 ms to 40 ms is generally applicable depending on the
operating (tripping) time of the relevant circuit breaker on the parallel line.
It is absolutely necessary that the transient blocking time TrBlk BlockTime (address 2110) is longer than
the duration of transients resulting from the inception or clearance of external short circuits. During this time the
send signal is blocked for the permissive overreach schemes POTT and UNBLOCKING if the protection had ini-
tially detected a reverse fault. In the case of blocking scheme BLOCKING, the blocking of the Z1B release is
prolonged by this time by both the detection of a reverse fault and the (blocking) received signal. After expira-
tion of TrBlk BlockTime (address 2110) the delay time Release Delay (address 2108) is restarted for
the blocking scheme. Since the blocking scheme always requires setting the delay time Release Delay, the
transient blocking time TrBlk BlockTime (address 2110) can usually be set very short. This parameter can
only be altered with DIGSI under Additional Settings.
Where the teleprotection schemes of the distance protection and earth fault protection share the same channel,
DIS TRANSBLK EF (address 2112) should be set to YES. This blocks also the distance protection if an external
fault was previously detected by the earth fault protection only.
Echo function
The echo function settings are common to all weak infeed measures and summarized in tabular form in Section
2.11.2.2.
Note
The „ECHO SIGNAL" (No. 4246) must be allocated separately to the output relays for the transmitter actuation,
as it is not contained in the transmit signals of the transmission functions.
214
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
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