Siemens SIPROTEC 7SJ62 Instruction Manual page 272

Functions
Blocking Time
Static Blocking
Dynamic Blocking
6-132
After the final circuit breaker trip, the automatic reclosing system is dynamically
blocked (see below).
The blocking time (reset time) is started each time a reclosing attempt is initiated. If
the reclosing attempt is successful, then the automatic reclosing system will reset
once the blocking time has elapsed. Occurrence of a fault after the blocking time is
considered a new fault, and the initiation of trip signals by protective elements for this
fault will initiate a new automatic reclosing sequence (and possibly execute a different
reclosing program, depending on the type of fault). When no additional reclosing at-
tempts are permitted, the last reclosing attempt will be considered unsuccessful, and
upon final tripping of the circuit breaker by the protective element(s), the automatic re-
closing system will be dynamically blocked (see below).
The automatic reclosing system is statically blocked for one or more of the following:
− A blocking signal (FNo.  "!%/2&.  ") is present at a binary input, if the au-
tomatic reclosing system is not initiated.
− A signal (FNo.  "!&% 5HDG\") indicating the circuit breaker is ready disap-
pears from a binary input, if the automatic reclosing system is not initiated.
− The number of allowable reclosing attempts set for both reclosing programs is zero.
− No protective functions or binary inputs are set to initiate the automatic reclosing
system.
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. When
static blocking takes place, a corresponding message is generated. The static block-
ing signal is also used internally to block the protection elements that are only sup-
posed to work when reclosing is enabled.
Dynamic blocking defeats the possibility of a reclosing attempt when certain events
occur. Dynamic blocking is initiated if:
− The final reclosing attempt was unsuccessful.
− The protection function has detected a three-phase fault and the device is pro-
grammed not to reclose into three-phase faults.
− The circuit breaker is tripped without initiation of the automatic reclosing system.
− A reclosing signal fails to close a circuit breaker.
− A protective element picks up that is set to block automatic reclosing (regardless of
whether one or more other protective functions set to initiate automatic reclosing
also pickup).
− The circuit breaker failure function is initiated.
− The reclosing program executed is programmed to initiate zero reclosing attempts.
− A static block occurs after initiation of the automatic reclosing function.
− Not applicable for version 7SJ61**–**C**– and 7SJ61**–**P**–: The circuit
breaker is not ready for operation after the circuit breaker monitoring time (set at
address  &+(&. &%") has elapsed, provided that the circuit breaker monitor
function is set to be in effect.
− Not applicable for version 7SJ61**–**A**– and 7SJ61**–**M**–: If the circuit
breaker is not ready for operation after the reclosing delay time (triggered by binary
7SJ62 Manual
C53000-G1140-C121-1