Before a release for closing is granted, the following conditions are checked:
•
Is the reference voltage V
1
above the setting value Vmin but below the maximum voltage Vmax?
•
Is the voltage V
2
to be synchronized above the setting value Vmin, but below the maximum voltage
Vmax?
•
Is the voltage difference V
2
– V
1
within the permissible limit dV SYNCHK V2>V1?
•
Is the voltage difference V
1
– V
2
within the permissible limit dV SYNCHK V2<V1?
•
Are the two frequencies f
1
and f
2
within the permissible operating range f
Nom
± 3 Hz?
•
Is the frequency difference f
2
– f
1
within the permissible limit df SYNCHK f2>f1?
•
Is the frequency difference f
1
– f
2
within the permissible limit df SYNCHK f2<f1?
•
Is the angle difference α
2
– α
1
within the permissible limit dα SYNCHK α2>α1?
•
Is the angle difference α
1
– α
2
within the permissible limit dα SYNCHK α2<α1?
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 CloseR-
elease
). 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 synchronous condi-
tions are met.
The measurement of the the synchronism conditions can be confined to the a maximum monitoring time T-
SYN. DURATION. If the conditions are not met within T-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
Nom
± 3 Hz
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
1
•
Value of the voltage to be synchronized V
2
•
Frequency values f
1
and f
2
•
Differences of voltage, frequency and angle.
Functions
2.20 Synchrocheck
SIPROTEC Compact, 7SC80, Manual 339
E50417-G1140-C486-A8, Edition 07.2017
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