active longer than necessary, the CMD_FAIL_AL alarm output is activated. To avoid
unnecessary alarms, the maximum length of the closing command signal should be
below
Maximum Syn time
+ 5 s.
CLOSE_CB
t = Maximum Syn time
CMD_FAIL_AL
t = 5 s
CL_COMMAND or
Synchronize CB
Figure 878: Determination of the alarm limit for a still-active command signal
The binary input BLOCK can be used to block the function. The activation of the
BLOCK input deactivates all binary outputs and resets the internal timers.
9.7.6 Application
A circuit breaker is used to connect two different power networks. It is essential
to ensure that these power networks are synchronized before closing the CB,
otherwise it may lead to disturbances in the power system, causing stress and
damage to the connected equipment.
ASNSCSYN can be used for the synchronized closing of a non-generator circuit
breaker such as a bus sectionalizer, a bus coupler or an incoming feeder. It
checks for the synchronization conditions across the CB and releases the CB
closing command. If these conditions are not fulfilled, the sources in the power
network connected across this bus coupler or tie feeder CB have to change their
operating points to meet the requirements. This is achieved with Autosynchronizer
co-ordinator ASCGAPC available with the source (ASGCSYN) function and non-
source (ASNSCSYN) function.
ASCGAPC assists in the participating sources selection based on the network
topology and interacts with the sources to initiate the voltage and frequency
matching for the bus coupler or tie feeder CB to be synchronized. When any non-
source circuit breaker (NSCB) is selected for synchronization, a synchronization
procedure is started. ASCGAPC located in the NSCB relay starts communicating
with ASCGAPCs of possible source circuit breaker (SCB) relays for matching the
voltage and frequency difference. Both ASCGAPCs pass the required information to
the participating sources. A non-source CB synchronization is described with one
typical example in
Figure 879
.
1MRS759142 F
Control functions
REX640
Technical Manual
1599
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