checking the synchronism. When synchronism is detected (according to the
settings), the
SYNC_OK
output is set to TRUE (logic '1') and it stays TRUE as long
as the conditions are fulfilled. The command input is ignored in the continuous
control mode. The mode is used for situations where Synchro check only gives the
permission to the control block that executes the CB closing.
SECRSYN
CBXCBR
I
Closing
permission
Closing
command
Figure 316: A simplified block diagram of the Synchro check function in the
continuous mode operation
Command mode
If
Control mode is set to "Command", the purpose of the Synchro check
functionality in the command mode is to find the instant when the voltages on both
sides of the circuit breaker are in synchronism. The conditions for synchronism are
met when the voltages on both sides of the circuit breaker have the same frequency
and are in phase with a magnitude that makes the concerned busbars or lines such
that they can be regarded as live.
In the command mode operation, an external command signal
CL_COMMAND
, besides
the normal closing conditions, is needed for delivering the closing signal. In the
command control mode operation, the Synchro check function itself closes the
breaker via the
SYNC_OK
output when the conditions are fulfilled. In this case, the
control function block delivers the command signal to close the Synchro check
function for the releasing of a closing-signal pulse to the circuit breaker. If the
closing conditions are fulfilled during a permitted check time set with
Maximum Syn
time, the Synchro check function delivers a closing signal to the circuit breaker after
the command signal is delivered for closing.
SECRSYN
CBXCBR
I
Closing
request
Closing
command
Figure 317: A simplified block diagram of SECRSYN in the command mode operation
1MRS758755 C
Control functions
REC615 & RER615
Technical Manual
647
