ABB RELION REX640 Technical Manual page 1468

Section 9
Control functions
1462
coupler or tie feeder CB have to adjust their voltage and frequency. ASCGAPC can be
used as coordinator for selection and coordination with the sources, during the
synchronization of any bus coupler or tie feeder circuit breaker. The function allows
the synchronization of only one circuit breaker at a time. In case of any conflict, the
synchronization process is stopped.
As a coordinator the function 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 selected for synchronization, any NSCB communicates with ASCGAPC for
matching of voltage and frequency difference. ASCGAPC passes the required
information to the participating sources along with their active status. An NSCB
synchronization is described with one typical example in
Source
2
ASGCSYN
(SCB2)
ASCGAPC
ASNSCSYN
(NSCB1)
ΔU, ΔF
ASCGAPC
GUID-6BC12E47-B175-4E30-872F-46B699909157 V1 EN
Figure 786: NSCB2 synchronization
In this application example, breaker NSCB2 must be closed so the synchronizing
conditions between Bus1 and Bus2 are checked by ASNSCSYN. ASNSCSYN sends
the autosynchronization request and voltage and frequency difference (ΔU, ΔF)
between the Bus1 and Bus2 to the Autosynchronization coordinator functions
ASCGAPC.
ASCGAPC transfers the voltage and frequency difference sent by ASNSCSYN to the
ASCGAPC of source 1 ASGCSYN function as well as to the ASCGAPC of source 2
ASGCSYN function. It also sends the permission to the source to start matching the
voltage and frequency. The matching process is carried out so that the voltage and
frequency difference between Bus1 and Bus2 measured by ASNSCSYN reduces and
comes within the synchrocheck limits. This satisfies the synchrocheck conditions for
breaker NSCB2 which can then be synchronized by ASNSCSYN.
Source
1
ASGCSYN
(SCB1)
ASCGAPC
Bus1
Start Matching
ASNSCSYN
ΔU, ΔF
(NSCB2)
ASCGAPC
1MRS759142 C
Figure 786.
ASNSCSYN
(NSCB3)
ASCGAPC
Bus2
Synchronize
REX640
Technical Manual