9.6.6 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 circuit
breaker, otherwise it may lead to disturbances in the power system, causing stress
and damage to the connected equipment.
ASGCSYN controls the closing of the generator circuit breakers in power networks;
it enables the closing after matching the voltage and frequency conditions to
achieve synchronism. ASGCSYN also participates in matching voltage and frequency
conditions for the network breaker synchronization.
ASGCSYN includes both the synchronization check function and the energizing
function to allow closing when one side of the breaker is dead.
The participation of ASGCSYN in matching of voltage and frequency conditions for
the network breaker synchronization is described via one of the typical application
example as shown in
Figure 868
.
Source
2
ASNSCSYN
(NSCB2)
ASCGAPC
ASGCSYN
(SCB2)
ASGCSYN
(SCB1)
∆U, ∆F
Synchronize
Start
Matching
Bus1
Bus2
Source
1
ASNSCSYN
(NSCB3)
ASCGAPC
ASNSCSYN
(NSCB1)
ASCGAPC
ASCGAPC
ASCGAPC
Figure 868: ASGCSYN participation in matching of V, F during network breaker
synchronization
In this application example, breaker NSCB2 must be closed, so the synchronizing
conditions between the Bus1 and Bus2 power systems are checked by the
autosynchronizer for network breaker function ASNSCSYN. If the synchro check
conditions are not met, then ASNSCSYN sends the auto synchronization request
and voltage and frequency difference (ΔU, ΔF) between Bus1 and Bus2 to the
autosynchronizer co-ordinator function ASCGAPC.
ASCGAPC transfers the voltage and frequency difference sent by ASNSCSYN to the
ASCGAPC of the generator1 ASGCSYN function. It also sends permission to the
generator to start matching the voltage and frequency. The generator's ASGCSYN
function gives the raise or lower pulses to AVR and governor to raise or lower their
voltage and frequency on Bus2. 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.
Voltage angle difference adjustment
In applications where the power transformer is located between the voltage
measurement and the generator circuit breaker, the vector group connection gives
1MRS759142 F
Control functions
REX640
Technical Manual
1579
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