NR Electric PCS-9611, Instruction Manual

Page: 91 / 300

3 Operation Theory
PCS-9611 Feeder Relay
3-55
Date: 2014-04-08
When the auto-reclosing command is issued, the reclaim timer starts. If the circuit breaker does
not trip again, the auto-recloser resets at the end of the reclaim time. If the protection operates
during the reclaim time delay [79.t_Reclaim], this relay either advances to the next shot in the
programmed auto-reclosing cycle, or it goes to lockout if all programmed reclose attempts have
been made. The reclaim time should be set long enough to allow this relay to operate when the
circuit breaker is automatically closed onto a fault.
If any blocking condition is met in the process of the auto -recloser, the auto-recloser will be
blocked at once. And if any shot of the auto-recloser can not operate successfully, the signal
[79.Fail] will be issued.

Single-shot Reclosing
When a trip signal is programmed to initiate the automatic reclosing system, the appropriate
automatic reclosing program will be executed. Once the circuit breaker has opened, a dead
time interval in accordance with the type of fault is started. Once the dead time interval has
elapsed, a closing signal is issued to reclose the circuit breaker.
If the fault is cleared, the reclaim time expires and the automatic reclosing is reset in
anticipation of a future fault. The fault is cleared.
If the fault is not cleared, then a final tripping signal is initiated by one or more protective
elements.

Multi-shot Reclosing
This relay permits up to 4 shots of reclosing. The shot number of reclosing can be set. The
first reclose cycle is, in principle, the same as the single-shot auto-reclosing. If the first
reclosing attempt is unsuccessful, this does not result in a final trip, but in a reset of the
reclaim time interval and start of the next reclose cycle with the next dead time. This can be
repeated until the shot number of reclosing has been reached.
If one of the reclosing attempts is successful, i.e. the fault disappeared after reclosing, the
reclaim time expires and the automatic reclosing system is reset. The fault is terminated.
If none of the reclosing attempts is successful, then a final circuit breaker trip will take place
after the last allowable reclosing attempt has been performed by the protection function. All
reclosing attempts were unsuccessful.
After the final circuit breaker trip, the automatic reclosing system is dynamically blocked.
An example of a timing diagram for a successful second reclosing is shown as below.