Siemens SIPROTEC 7RW80 Manual page 91

Release
The synchronizing function only operates if it receives a measurement request. This request may be issued by
the internal control function or externally via a binary input, e.g. from an external automatic reclosing system.
Before a release for closing is granted, the following conditions are checked:
• Is the reference voltage V
• Is the voltage V
• 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
• Is the angle difference α
• Is the angle difference α
If there is a condition which is not plausible, the message „25 Sync. Error" is output and the measurement
is not started. the conditions are plausible, the measurement is started (message „25-1 meas.") and the
configured release conditions are checked.
Each condition which is met is indicated explicitly (messages „25 Vdiff ok", „25 fdiff ok", „25 αdiff
ok"). Conditions which are not met are also indicated explicitly, e.g. when the voltage difference (messages
„25 V2>V1", „25 V2<V1"), frequency difference (messages „25 f2>f1", „25 f2<f1") or angle difference
(messages „25 α2>α1", „25 α2<α1") is outside the limit values. The precondition for these messages is
that both voltages are within the operating range of the synchrocheck function (see „Operating Range").
If the conditions are met, the synchrocheck function issues a release signal for closing the relay („25
CloseRelease"). This release signal is only available for the configured duration of the CLOSE command
and is processed by the device's function control as CLOSE command to the circuit breaker (see also margin
heading „Interaction with Control"). However, the message „25 Synchron" is applied as long as the synchro-
nous conditions are met.
The measurement of the the synchronism conditions can be confined to the a maximum monitoring time SYN.
DURATION. If the conditions are not met within SYN. DURATION, the release is cancelled (message „25
MonTimeExc"). A new synchronization can only be performed if a new measurement request is received.
Operating Range
The operating range of the synchrocheck function is defined by the configured voltage limits Vmin and Vmax
as well as the fixed frequency band f
If the measurement is started and one of or both voltages are outside the operating range or one of the voltages
leaves the operating range, this is indicated by corresponding messages („25 f1>>", „25 f1<<", „25
V1>>", „25 V1<<").
Measured Values
The measured values of the synchrocheck function are displayed in separate windows for primary, secondary
and percentaged measured values. The measured values are displayed and updated only while the synchro-
check function is requested.
The following is displayed:
• Value of the reference voltage V
• Value of the voltage to be synchronized V
• Frequency values f
• Differences of voltage, frequency and angle.
SIPROTEC, 7RW80, Manual
C53000-G1140-C233-1, Release date 10.2010
above the setting value Vmin but below the maximum voltage Vmax?
1
to be synchronized above the setting value Vmin but below the maximum voltage Vmax?
2
within the permissible limit dV SYNCHK V2>V1?
– V
2 1
within the permissible limit dV SYNCHK V2<V1?
– V
1 2
and f within the permissible operating range f
1 2
– f within the permissible limit df SYNCHK f2>f1?
2 1
within the permissible limit df SYNCHK f2<f1?
– f
1 2
within the permissible limit dα SYNCHK α2>α1?
– α
2 1
within the permissible limit dα SYNCHK α2<α1?
– α
1 2
± 3 Hz.
Nom
1
and f
1 2
2
Functions
2.7 SYNCHROCHECK 25
± 3 Hz?
N
91