Siemens siprotec 7SD5 User Manual page 306

2 Functions
The action time 1.AR: T-ACTION (address 3451) is the timeframe after initiation
(fault detection) by any protective function which can start the automatic reclosure
function within which the trip command must appear. If no trip command is issed until
the action time has expired, there is no reclosure. Depending on the configuration of
the protective functions, the action time may also be omitted; this applies especially
when an initiating protective function has no fault detection signal.
Depending on the configured operating mode of the automatic reclosure (address 134
AR control mode) only address 3456 and 3457 (if AR control mode = with
TRIP...) are available or address 3453 to 3455 (if AR control mode = with
PICKUP ...).
If AR control mode = with TRIP ..., you can set different dead times for single-
pole and three-pole reclose cycles. Whether single-pole or three-pole tripping takes
place depends solely on the initiating protection functions. Single-pole tripping is only
possible of course if the device and the corresponding protective function are also
capable of single-pole tripping.
Table 2-13
If only single-pole reclosure cycles are required, set the dead time for three-pole trip-
ping to ∞. If only three-pole reclosure cycles are required, set the dead time for single-
pole tripping to ∞; the protection then trips three-pole for every fault type.
The dead time after single-pole tripping (if set) 1.AR Tdead1Trip (address 3456)
should be long enough for the short-circuit arc to be extinguished and the surrounding
air to be de-ionized so that the reclosure promises to be successful. The longer the
line, the longer is this time due to the charging of the conductor capacitances. Con-
ventional values are 0.9 s to 1.5 s.
For three-pole tripping (address 3457 1.AR Tdead3Trip), the stability of the
network is the main concern. Since the de-energized line cannot transfer synchroniz-
ing energy, only short dead times are allowed. The usual values are 0.3 s to 0.6 s. If
the device is operating with a synchronism check device, a longer dead time may be
tolerated under certain circumstances. Longer three-pole dead times are also possible
in radial networks.
For AR control mode = with PICKUP ... it is possible to make the dead times
dependent on the type of fault detected by the initiating protection function(s).
Table 2-14
If the dead time is to be the same for all types of faults, set all three parameters the
same. Note that these settings only cause different dead times for different pickups.
The tripping can only be three-pole.
With the setting in address 3407 EV. FLT. MODE starts 3p AR, it is possible to
apply a separate dead time 1.AR: Tdead EV. (address 3458) for the three-pole
dead time after clearance of the sequential fault (see above at heading „General").
Stability aspects are also decisive here. Normally the setting constraints are similar to
address 3457 1.AR Tdead3Trip.
306
AR control mode = with TRIP...
3456 1.AR Tdead1Trip
3457 1.AR Tdead3Trip
AR control mode = with PICKUP ...
3453 1.AR Tdead 1Flt
3454 1.AR Tdead 2Flt
3455 1.AR Tdead 3Flt
is the dead time after single-pole tripping,
is the dead time after three-pole tripping.
is the dead time after single-phase pickup,
is the dead time after two-phase pickup,
is the dead time after three-phase pickup.
7SD5 Manual
C53000-G1176-C169-1