Siemens siprotec SJ62 User Manual page 287

2 Functions
Functional Se-
quence
Plausiblity Check /
SYNC Error
285
ditions it is not. The circuit breaker operating time is not taken into consideration. The
SYNCHROCHECK mode is used. It corresponds to the classic synchrocheck function.
On the other hand, asynchronous systems include bigger differences and the time
window for switching passes relatively quick. It is useful to consider the operating time
of the circuit breaker. The ASYN/SYNCHRON mode is used.
The synchrocheck function only operates if it receives a measurement request. This
request may be issued by the control, the automatic reclosing function or externally
via binary input, e.g. from an external automatic reclosing system.
The measurement request performs certain plausibility checks (for further information
see „Plausibility Check"). If there is a condition which is not plausible, a message „25
Sync. Error" is output. The measurement is then not carried out. If conditions are
plausible, measurement is initiated (message „25x meas."; with x = 1..n, according
to the function group). Depending on the selected operating mode, the configured
release conditions are then checked (see margin headings „Synchrocheck" / „Syn-
chronous/Asynchronous").
Each condition met is indicated explicitly (messages „25 Vdiff ok", „25 fdiff
ok", „25 αdiff ok"). Also conditions not fulfilled are indicated, for example, when
voltage differences (messages „25 V2>V1", „25 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 synchrocheck function issues a release signal for
closing the breaker („25 CloseRelease"). This release signal is only available for
the configured duration of the CLOSE command and is always processed by the con-
trol, which issues the actual CLOSE command for controlling the circuit breaker (see
also margin heading „Interaction with the control"). The annunciation „25
Synchron" is applied as long as the synchronous conditions are fulfilled.
Measuring the synchronism conditions can be confined to a maximum monitoring time
T-SYN. DURATION. If the conditions are not fulfilled during T-SYN. DURATION, the
release is cancelled (message „25 MonTimeExc"). A new synchrocheck can only
be performed if a new measurement request is received.
A parameter plausibility check is carried out upon device startup. Message „25 Set-
Error" is displayed if a fault is detected. If an implausible condition is detected after
a measurement request, message „25 Sync. Error" is generated. The measure-
ment is not initiated in that case.
The following plausibility checks are carried out:
• Checking unique function group identification
• Checking the configuration
• Evaluation of monitoring functions
If one and the same SYNC function group has multiple selections, error message „25
FG-Error" is output additionally. The synchrocheck cannot be bypassed via binary
input.
Concerning configuration it is also checked if power system address 213 is set to
Van,Vbn,Vcn,VSy. Otherwise message „25 Sync. Error" is output. Further-
more, specific thresholds and settings of the selected function group are checked. If
there is a condition which is not plausible, error message „25 Set-Error" is output
additionally. Here, please make sure that Address 6x06 (threshold V1, V2 energized)
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015