Siemens SIPROTEC 4 User Manual page 291

Functional Sequence
The synchronization function only operates if it receives a measurement request. This request may be issued
by the control, the automatic reclosing function or externally via a binary input e.g., from an external auto-
matic reclosing system.
The measurement request performs certain plausibility checks (for further information see "Plausibilty Check").
If there is a condition which is not plausible, the message
then not performed. If conditions are plausible, measurement is initiated (message
1..n, according to the function group). Depending on the selected operating mode, the configured release
conditions are then checked (see margin heading titles "Synchrocheck" / "Synchronous/Asynchronous").
Each condition met is indicated explicitly (messages
conditions not fulfilled are indicated, for example, when voltage differences (messages
V2<V1 ), frequency differences (messages 25 f2>f1 , 25 f2<f1 ) or angle differences (messages 25 α2>α1 ,
25 α2<α1 ) lie outside the threshold values. For these messages to be sent, both voltages must lie within the
operating range of the synchrocheck (see margin heading "Operating Range").
If these conditions are met, the synchronization function issues a release signal for closing the breaker (
CloseRelease ). This release signal is only available for the configured duration of the CLOSE command and
is always processed by the control, which issues the actual CLOSE command for controlling the circuit breaker
(see also margin heading "Interaction with Control"). The message
synchronous are fulfilled.
Measuring the synchronism conditions can be confined to the a maximum monitoring time T-SYN. DURA-
TION. If the conditions are not fulfilled during T-SYN. DURATION, the release is cancelled (message
MonTimeExc ). A new synchronization can only be performed if a new measurement request is received.
Validity Check / SYNC Error
During startup of the device a parameter validation check is performed. When there is a fault, the message
Set-Error is produced. If after a measurement request there is a condition which is not plausible, the
message 25 Sync. Error is output. The measurement is then not initiated.
The following plausibility checks are carried out:
•
Checking unique function group identification
•
Checking the configuration
•
Evaluation of monitoring functions
If one and the same function group has multiple selections, error message
ally. The synchronization function cannot be controlled via a binary input.
Concerning configuration it is also checked if power system address 213 is set to Van,Vbn,Vcn,VSy. Other-
wise, the message
function group are checked. If there is a condition which is not plausible, the error message
output additionally. Please ensure in this case that address 6x06 (threshold V
address 6x03 (lower voltage limit Vmin). The synchronization function cannot be controlled via a binary input.
If the monitoring function Fuse Failure Monitor is used and if it has picked up at the time as the measurement
of the synchronization was requested, the synchronization is not started either (message
The same applies if a voltage transformer failure (m.c.b. tripping) is communicated to the device via binary
input 6509 >FAIL:FEEDER VT or. 6510 >FAIL: BUS VT . In this case, the synchronization can be
controlled directly via a binary input.
In case of a protection pickup, the complete synchronization process is reset instantaneously.
Operating Range
The operating range of the synchronization function is defined by the configured voltage thresholds Vmin and
Vmax, and the fixed frequency band f
If measurement is started and one or both voltages are outside the operating range, or one voltage leaves the
permissible range, corresponding messages indicate this behavior (
etc.).
SIPROTEC 4, 7SJ62/64, Manual
C53000-G1140-C207-8, Edition 08.2016
25 Sync. Error is output. Furthermore, specific thresholds and settings of the selected
± 3 Hz.
Nom
25 Sync. Error is output. The measurement is
25 Vdiff ok , 25 fdiff ok , 25 αdiff ok ). Also
25 Synchron is applied as long as the
25 FG-Error is output addition-
, V
1
25 f1>> , 25 f1<< , 25 V1>> , 25 V1<< ,
Functions
2.21 Synchronization Function
„25x meas." ; with x =
25 V2>V1 , 25
25
25
25
25 Set-Error is
energized) is smaller than
2
25 Sync. Error ).
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