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• If there is a differential current in the size of twice the through-flowing current, you
• Finally, open the circuit breaker again.
• If parameter settings have been changed for the tests, reset them to the values
Figure 3-28
3.3.9
Check of the Signal Transmission for Internal and External Remote Tripping
The 7SD610 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 pre-
vious 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.
For the remote transmission, the external command input is employed on the receiv-
ing line end; it is therefore a prerequisite that: DTT Direct Trip is set in address
122 Enabled and FCT Direct Trip is set in address 2201 ON. If the signal trans-
mission path is the same and has already been checked as part of the previous sec-
tions, 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.
7SD610 Manual
C53000-G1176-C145-4
may assume a polarity reversal of the current transformer(s) at one line end. Again
check the polarity and set it right after short-circuiting all the three current transform-
ers. If you have modified these current transformers, also perform a power or angle
test.
necessary for operation.
Differential and restraint currents - Example of plausible measurements
3.3 Commissioning
315
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