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Mounting and Commissioning
3.3 Commissioning
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 re-set to the prescribed values.
3.3.13
Check of the Signal Transmission for Breaker Failure Protection and/or End
Fault Protection
If the transfer trip command for breaker failure protection or stub fault 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.
3.3.14
Check of the Signal Transmission for Internal and External Remote Tripping
The 7SD5 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 as well as from any signal coming from an external protection or control device.
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 as part of the previous sections, 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 permissive underreach (under „Checking with Per-
missive Underreach Transfer Trip"); however the received signal causes a direct trip.
For the remote transmission, the external command input is employed on the receiving line end; it is therefore
a prerequisite that: DTT Direct Trip is set to Enabled in address 122 and FCT Direct Trip is set to
ON in address 2201. If the signal transmission path is the same and has already been checked as part of the
previous sections, it need not be checked again here. A function check is sufficient, whereby the externally
derived command is executed. For this purpose, the external tripping event is simulated and the response of
the circuit breaker at the opposite line end is verified.
3.3.15
Testing User-defined Functions
The device has a vast capability for allowing functions to be defined by the user, especially with the CFC logic.
Any special function or logic added to the device must be checked.
A general procedure cannot in the nature of things be specified. Configuration of these functions and the set
value conditions must be actually known beforehand and tested. Especially, possible interlocking conditions of
the switching devices (circuit breakers, isolators, grounding electrodes) must be observed and checked.
564
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
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