Transfer Trip Signal Transmission For Breaker Failure Protection And/Or Stub Protection; Signal Transmission For Intertripping And Direct Transfer Tripping - Siemens siprotec 7SA6 User Manual

Blocking Scheme
Important for All
Schemes

8.3.12.3 Transfer Trip Signal Transmission for Breaker Failure Protection and/or Stub Protection

8.3.12.4 Signal Transmission for Intertripping and Direct Transfer Tripping

7SA6 Manual
C53000-G1176-C133-1
Prerequisites: 7HOHSURWHFWLRQ IRU (DUWK IDXOW RYHUFXUU 7HOHSURW
() in address  (Section 5.1) is set to a comparison scheme with a blocking
signal, i.e. %ORFNLQJ; furthermore the setting in address  must be )&7 7HOHS
() 21. Naturally the corresponding send and receive signals must also be assigned
to the corresponding binary output and input.
For more information about the blocking scheme see Subsubsection 6.6.1.3. In the
case of the blocking scheme, communication between the line ends is necessary.
An earth fault in the reverse direction is simulated at the transmitting line end.
Subsequently, a fault at the receiving end in the direction of the line is simulated. This
can be achieved with a set of secondary injection test equipment at each end of the
line. As long as the transmitting end is transmitting, no trip signal must appear at the
receiving line end, except is this is as a result of one of the back up stages with a
longer delay time setting. After the simulated fault at the transmitting line end is
switched off, the receiving line end remains blocked for the duration of the transmit
prolongation time of the transmitting line end (6HQG 3URORQJ, address ). If
applicable, the transient blocking time of the receiving line end (7U%ON %ORFN7LPH,
address ) appears additionally if a finite delay time 7U%ON :DLW 7LPH (address
 ) has been set and exceeded.
This test must be executed at both line ends, in the case of three terminal lines at each
line end and for each transmission path. Please take note of the last margin heading
"Important for All Schemes"!
If the distance protection was switched off for the signal transmission tests, it may be
switched on now. If setting parameters were changed for the test (e.g. mode of the
echo function or timers for unambiguous observation of sequences), these must now
be reset to the prescribed values.
If the transfer trip command for breaker failure protection or stub protection is to be
transmitted to the remote end, this transmission must also be checked.
To check the transmission the breaker failure protection function is initiated by a test
current (secondary) with the circuit breaker in the open position. Make sure that the
correct circuit breaker reaction takes place at the remote end.
Each transmission path must be checked on lines with more than two ends.
The 7SA6 provides the possibility to transmit a remote trip signal to the opposite line
end if a signal transmission path is available for this purpose. This remote trip signal
may be derived from both an internally generated trip signal (intertrip) as well as from
any signal coming from an external protection or control device (direct transfer trip).
If an internal signal is used, the initiation of the transmitter must be checked. If the
signal transmission path is the same and has already been checked in one of the
previous subsections, it need not be checked again here. Otherwise the initiating
event is simulated and the response of the circuit breaker at the opposite line end is
verified.
In the case of the distance protection, the permissive underreach scheme may be
used to trip the remote line end. The procedure is then the same as was the case for
Installation and Commissioning
8-63