ABB RELION REX640 Technical Manual page 1396

Section 9
Control functions
1390
The Minimum Syn time setting time can be set, if required, to demand the minimum
time within which conditions must be simultaneously fulfilled before the SYNC_OK
output is activated.
The measured voltage, frequency and phase angle difference values between the two
sides of the circuit breaker are available as monitored data values U_DIFF_MEAS,
FR_DIFF_MEAS and PH_DIFF_MEAS. Also, the indications of the conditions that
are not fulfilled and thus preventing the breaker closing permission are available as
monitored data values U_DIFF_SYNC, PH_DIF_SYNC and FR_DIFF_SYNC.
These monitored data values are updated only when the Synchro check is enabled with
the Synchro check mode setting and the measured ENERG_STATE is "Both Live".
Continuous mode
The continuous mode is activated by setting the parameter Control mode to
"Continuous". In the continuous control mode, Synchro check is continuously
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.
Closing
permission
SECRSYN
GUID-E950D1FA-BF9C-4C66-99FA-B92B5ED67D24 V1 EN
Figure 741: 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
Closing
command
CBXCBR
1MRS759142 C
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REX640
Technical Manual