Siemens SIPROTEC 7SD610 Manual page 126

Functions
2.10 Automatic Reclosure Function (optional)
The integrated automatic reclosing function allows up to 8 reclosing attempts. The first four reclose cycles may
operate with different parameters (action and dead times, 1-/3-pole). The parameters of the fourth cycle apply
to the fifth cycle and onwards.
Activation and deactivation
The automatic reclosure function can be switched on and off by means of the parameter 3401 AUTO RECLOSE
via the system interface (if available) and via binary inputs (if allocated). The switch states are saved internally
(refer to Figure 2-45) and secured against loss of auxiliary supply. Basically, it can only be switched on from
where it had previously been switched off. To be active, the function must be switched on from all three switch-
ing sources.
Alteration of the switching state via setting or system interface is not possible during a running fault.
Figure 2-45
Selectivity before Reclosure
In order that automatic reclosure function can be successful, all faults on the entire overhead line must be
cleared at all line ends simultaneously — as fast as possible.
This is the usual case in differential protection schemes because the strict selective zone definition of the pro-
tected object by the current transformer sets always allows non-delayed tripping.
However, fast tripping of the protection may also be desired before reclosure after tripping by other short-circuit
protection functions. For this purpose, every short-circuit protection which can start the automatic reclosure
function has the possibility of initiating non-delayed tripping in at least one stage when the automatic reclosure
function is ready for the first reclosure cycle. Please note, however, that fast, non-selective tripping should be
avoided as long as the differential protection works properly: there should be no non-delayed tripping of the
overcurrent time protection as the backup protection function, even if reclosure ensues.
Fast tripping before reclosure is also possible with multiple reclosures. Appropriate links between the output
signals (e.g. 2nd reclosure ready: „AR 2.CycZoneRel") and the inputs for enabling/releasing non-delayed
tripping of the protection functions can be established via the binary inputs and outputs or the integrated user-
definable logic functions (CFC).
Initiation
Initiation of the automatic reclosure function means storing the first trip signal of a power system fault that was
generated by a protection function which operates with the automatic reclosure function. In case of multiple
reclosure, initiation therefore only takes place once, with the first trip command. This storing of the first trip
signal is the prerequisite for all subsequent activities of the automatic reclosure function. The starting is impor-
tant when the first trip command has not appeared before expiry of an action time (see below under „Action
times").
126
Activation and deactivation of the auto-reclosure function
SIPROTEC, 7SD610, Manual
C53000-G1176-C145-6, Release date 02.2011