Synchronous / Asynchronous - Siemens siprotec SJ62 User Manual

2 Functions

2.19.1.3 Synchronous / Asynchronous

Switching under
Synchronous
System Conditions
Switching under
Asynchronous
System Conditions
287
The operating mode ASYN/SYNCHRON uses the frequency slip of the two power
systems (parameter F SYNCHRON) to determine whether the power systems are asyn-
chronous to each other ("Switching under Asynchronous System Conditions") or syn-
chronous ("Switching under Synchronous System Conditions"). If systems are asyn-
chronous, the time window for switching is passed relatively quickly. Therefore, it is
reasonable to take into account the operating time of the circuit breaker. Thus the
device can issue the ON command at a time where asynchronous conditions prevail.
When the poles make contact the conditions will be synchronous.
It is also possible to generally take into account the operating time of the circuit break-
er, i.e. also with synchronous conditions prevailing.
Switching under synchronous conditions means that the ON command will be re-
leased as soon as the characteristic data (voltage difference, angle difference) are
within the thresholds specified by configuration.
Before granting a release for closing under synchronous conditions, the following con-
ditions are checked:
• Is the reference voltage V
voltage Vmax?
to be synchronized above the setting value Vmin but below the
• Is the voltage V
2
maximum voltage Vmax?
• Is the voltage difference V
• Is the voltage difference V
• Are the two frequencies f
• Is the frequency difference smaller than the configured threshold frequency differ-
ence F SYNCHRON which defines the transition from synchronous to asynchronous
systems?
• Is the angle difference α
• Is the angle difference α
As soon as all synchronism conditions are fulfilled, the message „25 Synchron" is
issued.
For switching under asynchronous system conditions the device determines the time
for issuing the ON command from the angle difference and the frequency difference
such that the voltages (of busbar and feeder) are identical at the instant the poles
make contact. For this purpose the device must be informed of the operating time of
the circuit breaker for closing.
Before a release is granted, the following conditions are checked:
• Is the reference voltage V
voltage Vmax?
to be synchronized above the setting value Vmin but below the
• Is the voltage V
2
maximum voltage Vmax?
• Is the voltage difference V
• Is the voltage difference V
• Are the two frequencies f
• Is the frequency difference f
• Is the frequency difference f
above the setting value Vmin but below the maximum
1
within the permitted threshold dV SYNC V2>V1?
– V
2 1
within the permitted threshold dV SYNC V2<V1?
– V
1 2
and f within the permitted operating range f
1 2
– α within the permitted threshold dα SYNC α2> α1?
2 1
– α within the permitted threshold dα SYNC α2< α1?
1 2
above the setting value Vmin but below the maximum
1
within the permitted threshold dV ASYN V2>V1?
– V
2 1
within the permitted threshold dV ASYN V2<V1?
– V
1 2
and f within the permitted operating range f
1 2
within the permitted threshold df ASYN f2>f1?
– f
2 1
within the permitted threshold df ASYN f2<f1?
– f
1 2
Nom
Nom
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015
± 3 Hz?
± 3 Hz?