Blocking - Siemens siprotec SJ62 User Manual

2 Functions
Restraint Time

2.14.2 Blocking

Static Blocking
Dynamic Blocking
233
After the final circuit breaker trip, the automatic reclosing system is dynamically
blocked (see below).
The function of the restraint time has already been described in the paragraphs at side
title "Single-/Multi-Shot Reclosing". The restraint time can be prolonged when the fol-
lowing conditions are fulfilled.
The time 211 TMax CLOSE CMD defines the maximum time during which a close
command can apply. If a new trip command occurs before this time has run out, the
close command will be aborted. If the time TMax CLOSE CMD is set longer than the
restraint time TIME RESTRAINT, the restraint time will be extended to the remaining
close command duration after expiry!
A pickup from a protective function that is set to initiate the automatic reclosing system
will also lead to an extension of the restraint time should it occur during this time!
Static blocking means that the automatic reclosing system is not ready to initiate re-
closing, and cannot initiate reclosing as long as the blocking signal is present. A cor-
responding message „79 is NOT ready" (FNo. 2784) is generated. The static
blocking signal is also used internally to block the protection elements that are only
supposed to work when reclosing is enabled (see also side title "Reclosing Before Se-
lectivity" further above).
The automatic reclosing system is statically blocked if:
• The signal „>BLOCK 79" FNo.2703) is present at a binary input, as long as the
automatic reclosing system is not initiated (associated message: „>BLOCK 79"),
• The signal „>CB Ready" (FNo. 2730) indicates that the circuit breaker disappears
via the binary input, if the automatic reclosing system is not initiated (associated
message: „>CB Ready"),
• The number of allowable reclosing attempts set for both reclosing programs is zero
(associated message: „79 no cycle"),
• No protective functions (parameters 7150 to 7163) or binary inputs are set to ini-
tiate the automatic reclosing system (associated message: „79 no starter"),
• The circuit breaker position is reported as being "open" and no trip command
applies (associated message: „79 BLK: CB open"). This presumes that
7SJ62/63/64 is informed of the circuit breaker position via the auxiliary contacts of
the circuit breaker.
Dynamic blocking of the automatic reclosure program occurs in those cases where the
reclosure program is active and one of the conditions for blocking is fulfilled. The
dynamic blocking is signalled by the message „79 DynBlock". The dynamic block-
ing is associated to the configurable blocking time SAFETY 79 ready. This blocking
time is usually started by a blocking condition that has been fulfilled. After the blocking
time has elapsed the device checks whether or not the blocking condition can be reset.
If the blocking condition is still present or if a new blocking condition is fulfilled, the
blocking time is restarted. If, however, the blocking condition no longer holds after the
blocking time has elapsed, the dynamic blocking will be reset.
SIPROTEC 4, 7SJ62/63/64 Handbuch
C53000-G1140-C147-A, Edition 07.2015