Siemens SIPROTEC 7SA522 Manual page 261

Operating Modes
7SA522 Manual
C53000-G1176-C155-3
The synchronism check function only operates when it is requested to do so. Various
possibilities exist to this end:
• Measuring request from the internal automatic reclosure device. If the internal au-
tomatic reclosing function is set accordingly (one or more reclosing attempts set to
synchronism check, see also Section 2.13.2), the measuring request is accom-
plished internally. The release conditions for automatic reclosing apply.
• Measuring request from an external automatic reclosure device. The measuring
request must be activated via the binary input ´!6\QF 6WDUW $5µ (FNo 2906).
The release conditions for automatic reclosing apply.
• Measuring request from the internal manual CLOSE detection. The manual CLOSE
detection of the central function control (Section 2.20.1) issues a measuring request
provided this was configured in the power system data 2 (Section 2.1.5.1, address
). This requires the device to be informed of the manual closing via binary
input ´!0DQXDO &ORVHµ (FNo 356). The release conditions for manual reclosing
apply.
• Request to execute a check synchronism measurement from an external closing
command. Binary input ´!6\QF 6WDUW 0&µ FNo. 2905 fulfills this purpose.
Unlike the ´!0DQXDO &ORVHµ (see previous paragraph), this merely affects the
measuring request to the synchronism check function, but not other integrated
manual CLOSE function such as instantaneous tripping when switching onto a fault
(e.g. overreaching zone for distance protection or accelerated tripping of a time
overcurrent stage). The release conditions for manual closure apply.
• Measuring request from the integrated control function via control keys or via the
serial interace using DIGSI
tions for manual closure apply.
The synchronism check function gives permission for passage ´6\QF UHOHDVHµ
(FNo 2951) of the closing command to the required function. Furthermore a separate
closing command is available as output indication ´6\QF&ORVH&PGµ (FNo 2961).
The check of the release conditions is limited by an adjustable synchronous monitor-
ing time 76<1 '85$7,21. The configured conditions must be fulfilled within this
time. Otherwise synchronism will not be checked. A new synchronism check se-
quence requires a new request.
The device outputs messages if, after a request to check synchronism, the conditions
for release are not fulfilled, i.e. if the absolute voltage difference 0D[ 9ROW 'LII,
the absolute frequency difference 0D[ )UHT 'LII, or the absolute phase angle
difference 0D[ $QJOH 'LII lie outside the permissible limit values. A precondition
for these messages is that voltages within the operating range of the relay are avail-
able. When a closing command is handled by the integrated control function and the
conditions for synchronism are not fulfilled, the command is cancelled i.e., the control
function outputs "CO–" (refer also to Section 2.22.1).
The closing check procedure can be selected from the following operating modes:
6<1&&+(&. =
8V\QF! 8OLQH =
8V\QF 8OLQH! =
2.14 Synchronism and voltage check (optional)
®
on a PC or from a control center. The release condi-
Release at synchronism, that is, when the critical
values 0D[ 9ROW 'LII, 0D[ )UHT 'LII and
0D[ $QJOH 'LII lie within the set limits.
Release for energized busbar (Ubus>) and de-ener-
gized line (Uline<).
Release for de-energized busbar (Ubus<) and ener-
gized line (Uline>).
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