Siemens SIPROTEC 4 7VK61 - Page 85

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Request to execute a check synchronism measurement from an external closing command. Binary input
>Sync. Start MC (No. 2905) fulfills this purpose. Unlike >Manual Close (see previous paragraph),
this merely affects the measuring request to the synchronism check function, but not other integrated
manual CLOSE functions such as instantaneous tripping when switching onto a fault (e.g. accelerated
tripping of a time overcurrent stage). The release conditions for manual closure apply (parameter MC...).
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Measuring request from the integrated control function via control keys or via the serial interface using
DIGSI on a PC or from a control centre. The release conditions for manual closure apply (parameter
MC...).
The synchronism-check function gives permission for passage Sync. release (No. 2951) of the closing
command to the required function. Furthermore, a separate closing command is available as output indication
Sync.CloseCmd (No. 2961).
The check of the release conditions is limited by an adjustable synchronous monitoring time T-SYN. DURA-
TION. The configured conditions must be fulfilled within this time. If they are not, the synchronism will not be
checked. A new synchronism check sequence requires a new request.
The device generates messages if, after a request to check synchronism, the conditions for release are not
fulfilled, i.e. if the absolute voltage difference AR maxVolt.Diff or MC maxVolt.Diff, frequency differ-
ence AR maxFreq.Diff or MC maxFreq.Diff or angle difference AR maxAngleDiff or MC maxAngle-
Diff lie outside the permissible limit values. A precondition for these indications is that voltages within the
operating range of the relay are available. When a closing command originates from the integrated control
function and the conditions for synchronism are not fulfilled, the command is cancelled, i.e. the control func-
tion outputs “CO– ” (refer also to Section 2.10.1 Control Authorization).
Functions
2.4 Synchronism and voltage check (optional)
SIPROTEC 4, 7VK61, Manual 85
C53000-G1176-C159-5, Edition 05.2018