ABB RELION REX640 Technical Manual page 1448

Section 9
Control functions
1442
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 775.
Source
2
ASGCSYN
(SCB2)
ASCGAPC
ASNSCSYN
(NSCB1)
ASCGAPC
∆U, ∆F
GUID-6B72758A-8BE6-4E9C-9E67-8F0953E04283 V1 EN
Figure 775: 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 auto synchronization request and the voltage and frequency difference (ΔU, ΔF)
between Bus1 and Bus2 to ASCGAPC.
ASCGAPC transfers the voltage and frequency difference sent by ASNSCSYN to the
selected ASCGAPC function of source 1 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 synchro check limits.
This satisfies the synchro check conditions for breaker NSCB2 which can then be
synchronized by ASNSCSYN. Similarly, the synchronization of NSCB1 and NSCB3
having ASCGAPC is done as shown in
Source
1
ASGCSYN
(SCB1)
ASCGAPC
Bus1
∆U, ∆F
ASNSCSYN
(NSCB2)
ASCGAPC
NS_ASC_DAT
Matching Start
Synchronize
Figure 776 and
1MRS759142 C
ASNSCSYN
(NSCB3)
ASCGAPC
Bus2
NS_ASC_DAT
Figure 777.
REX640
Technical Manual