Siemens siprotec 7SA6 User Manual page 368

Functions
Configuration of
the Automatic
Reclosure Function
Forced Three-pole
Trip
Dead Line Check/
Reduced Dead
Time
6-186
energy transport until the remote end has also closed. This delay must therefore be
added to the dead time for consideration of the network stability.
This configuration concerns the interaction between the protection and supplementary
functions of the device and the automatic reclosure function. The selection of functions
of the device which are to start the automatic reclosure circuit and which are not to, is
made here.
In the 7SA6 this concerns:
Address  $5 Z ',67, i.e. with distance protection,
Address  $5 Z 627)2&, i.e. with high–current fast tripping,
Address  $5 Z :,, i.e. with weak-infeed trip function,
Address  $5 Z ()2&, i.e. with transfer trip and remote trip,
Address  $5 Z '77, i.e. with externally coupled trip command,
Address  $5 Z %DFN8S2&, i.e. with time-overcurrent protection.
For the functions which are to start the automatic reclosure, the corresponding
address is set to <HV, for the others to 1R. The other functions (overvoltage protection,
overload protection) cannot start the automatic reclosure because reclosure is of no
use here.
If reclosure is blocked during the dead time of a single-pole cycle without a three-pole
trip command having been given, the line remains interrupted single-pole. With
address  $5 75,3 SROH it is possible to determine that the tripping logic of the
device issues a three-pole trip command in this case (pole discrepancy prevention for
the CB poles). Set this address to <HV if the CB can be tripped single-pole and has no
pole discrepancy protection itself. Nevertheless, the device pre-empts the pole
discrepancy protection of the CB poles because the forced three-pole trip of the device
is immediately activated as soon as the reclosure is blocked following a single-pole
trip or if the CB auxiliary contacts indicate a non plausible switching state (see also
section 6.12.1 under subtitle "Processing the Circuit Breaker Auxiliary Contacts"). The
forced three-pole trip is also activated when only three-pole cycles are allowed but a
single-pole trip is signalled externally via a binary input.
The forced three pole trip is unnecessary if only a common three-pole control of the
CB is possible.
Under address  the dead line check or the reduced dead time function can be
activated. Either the one or the other can be used as the two options are contradictory.
The voltage transformers must be connected to the line side of the circuit breaker if
either of these modes is to be used. If this is not the case or if neither of the two
functions is used, set '/& RU 5'7 = :,7+287. If the adaptive dead time is used (see
below), the parameters mentioned here are omitted because the adaptive dead time
implies the properties of the reduced dead time.
'/& RU 5'7 = '/& means that the dead line check of the line voltage is used. This
only enables reclosure after it becomes apparent that the line has been dead. In this
case, the setting 8GHDG under address  determines the limit voltage, phase–
earth,below which the line is considered to be definitely dead (disconnected). The
setting is applied in Volts secondary. This value can be entered as a primary value
when parametrizing with a PC and DIGSI
the measuring time available for determining the no-voltage condition. Address 
is irrelevant here.
'/& RU 5'7 = 5'7 means that the reduced dead time is used. This is described in
detail in section 6.12.1 under subtitle "Reduced Dead Time (RDT)", page 6-175. In this
case the setting under address  8OLYH! determines the limit voltage, phase–
® 4. Address  7 8VWDEOH determines
7SA6 Manual
C53000-G1176-C133-1