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Functions
2.17 Automatic Reclosure Function (optional)
For the line end with defined dead times the number of desired reclose cycles must be set during the configu-
ration of the protection functions (Section 2.1.1) in address 133 Auto Reclose. Additionally, the intertrip
command of the differential protection should be activated (see Section 2.4, address 1301 I-TRIP SEND =
YES). For the devices operating with adaptive dead time, address 133 Auto Reclose must have been set to
ADT during the configuration of the protection functions (Section 2.1.1). Only the parameters described below
are interrogated in the latter case. No settings are then made for the individual reclosure cycles.
The adaptive dead time may be voltage-controlled or Remote–CLOSE–controlled. Both are possible at the
same time. In the first case, reclosure takes place as soon as the returning voltage, after reclosure at the remote
end, is detected. For this purpose the device must be connected to voltage transformers located on the line
side. In the case of Remote-CLOSE, the autoreclosure waits until the Remote-CLOSE command is received
from the remote end.
The action time T-ACTION ADT (address 3433) is started after any protection function has triggered the au-
tomatic reclosing function. The trip command must occur during this time. If no trip command is issued until the
action time has expired, reclosing will not be initiated. Depending on the configuration of the protection func-
tions (see Section 2.1.1.3), the action time may also be omitted; this applies especially when an initiating pro-
tection function has no fault detection signal.
The dead times are determined by the reclosure command of the device at the line end with the defined dead
times. In cases where this reclosure command does not appear, e.g. because the reclosure was in the mean-
time blocked at this end, the readiness of the local device must return to the quiescent state at some time. This
takes place after the maximum wait time T-MAX ADT (address 3434). It must be long enough to include the
last reclosure of the remote end. In the case of single-shot reclosing, the sum of the maximum dead time plus
reclaim time of the other device is sufficient. In the case of multiple reclosure, the worst case is that all reclo-
sures of the other end except the last one are unsuccessful. The time of all these cycles must be taken into
account. To save having to make exact calculations, it is possible to use the sum of all dead times and all pro-
tection operating times plus one reclaim time.
Under address 3435 ADT 1p allowed it can be determined whether 1-pole tripping is allowed (provided that
1-pole tripping is possible). If NO, the protection trips 3-pole for all fault types. If YES, the actual trip signal of the
starting protection functions is decisive. If the reclaim time is unequal to 0 s and 1-pole tripping is allowed, 1-
pole tripping will be prevented during the reclaim time. Each fault is thus disconnected in three poles while the
reclaim time is active.
Address 3403 T-RECLAIM allows disabling the reclaim time in ADT mode. In doing so, the ADT cycle including
its settings and release conditions is restarted after unsuccessful automatic reclosing. If the reclaim time is ac-
tivated, the 1-pole trip permission at address 3435 and the protection releases are disabled while the reclaim
time is running.
Under address 3436 ADT CB? CLOSE it can be determined whether circuit breaker ready is interrogated
before reclosure after an adaptive dead time. With the setting YES, the dead time may be extended if the circuit
breaker is not ready for a CLOSE–OPEN–cycle when the dead time expires. The maximum extension that is
possible is the circuit breaker monitoring time; this was set for all reclosure cycles under address 3409 (see
above). Details about the circuit breaker monitoring can be found in the function description, Section 2.17, at
margin heading „Interrogation of the Circuit Breaker Ready State".
If there is a danger of stability problems in the network during a 3-pole reclosure cycle, set address 3437 ADT
SynRequest to YES. In this case a check is made before reclosure following a 3-pole trip whether the voltages
of feeder and busbar are sufficiently synchronous. This is only done on condition that either the internal syn-
chronism and voltage check functions are available, or that an external device is available for synchronism and
voltage check. If only 1-pole reclose cycles are executed or if no stability problems are expected during 3-pole
dead times (e.g. due to closely meshed networks or in radial networks), set address 3437 to NO.
Addresses 3438 and 3440 are only significant if the voltage-controlled adaptive dead time is used. 3440 U-
live> is the phase-to-earth voltage limit above which the line is considered to be fault-free. The setting must
be smaller than the lowest expected operating voltage. The setting is applied in volts secondary. This value can
be entered as a primary value when parameterising with a PC and DIGSI. Address 3438 T U-stable defines
the measuring time used to determine the voltage. It should be longer than any transient oscillations resulting
from line energization.
338
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
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