Check Of The Signal Transmission For Internal And External Remote Tripping - Siemens SIPROTEC 7SD610 Manual

• If there is a differential current in the size of twice the through-flowing current, you 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 transformers. If you have modified these current transformers, also perform a
power or angle test.
• Finally, open the circuit breaker again.
• If parameter settings have been changed for the tests, reset them to the values necessary for operation.
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 trans-
mission path is available for this purpose. This remote trip signal may be derived from both an internally gen-
erated 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.
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.
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011
Differential and restraint currents - Example of plausible measurements
Mounting and Commissioning
3.3 Commissioning
317