Siemens siprotec 7SA522 User Manual

2.13 Automatic reclosure function (optional)
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7SA522 Manual
C53000-G1176-C155-3
Adaptive Dead
Time (ADT)
When operating with adaptive dead time, it must be ensured in advance that one end
per line operates with defined dead times and has an infeed. The other (or the others
in multi-branch lines) may operate with adaptive dead time. It is essential that the
voltage transformers are located on the line side of the circuit breaker. Details about
this function can be found in section 2.13 at margin heading “Adaptive Dead Time
(ADT)”.
For the line end with defined dead times the number of desired reclose cycles must be
set during the configuration of the protective functions under address  $XWR
5HFORVH. For the devices operating with adaptive dead time $XWR5HFORVH must
be set to $'7 during the configuration of the protective functions under address .
Only the parameters described below are interrogated in the latter case. No settings
are then made for the individual reclosure cycles. The adaptive dead time implies
functionality of reduced dead time.
The adaptive dead time may be voltage-controlled or Remote–CLOSE–controlled.
Both is possible at the same time. In the first case reclosure takes place as soon as
the return voltage, after reclosure at the remote end, is detected. For this purpose the
device must be connected to voltage transformers located on the line side of the circuit
breaker. In the case of remote-close, the device waits until the remoteclose command
is received before issuing the reclose command.
The action time 7$&7,21$'7 (address ) is the time after initiation (fault de-
tection) by any protective function which can start the automatic reclosure function
within which the trip command must appear. If the command does not appear until
after the action time has expired, there is no reclosure. Depending on the configuration
of the protective functions (see section 2.1.1.2) the action time may also be omitted;
this applies especially when an initiating protective function has no fault detection
signal.
The dead times are determined by the reclosure command of the device at the line
end with the defined dead times. In cases where this reclosure command does not
appear, e.g. because the reclosure was in the mean time blocked there, the readiness
of the local device must return to the quiescent state at some time. This takes place
after the maximum wait time 70$;$'7 (address ). This must be long enough
to include the last reclosure of the remote end. In the case of single cycle reclosure,
the sum total of maximum dead time plus reclaim time of the other device is sufficient.
In the case of multiple reclosure the worst case is that all reclosures 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 protection operating times plus one reclaim time.
Under address  $'7SDOORZHG it can be determined whether single-pole trip-
ping is allowed (on condition that single-pole tripping is possible). If 12, the protection
trips three-pole for all fault types. If <(6 the possible tripping situations of the starting
protective functions are decisive.
Under address  $'7&%"&/26( it can be determined whether circuit-breaker
ready is interrogated before reclosure after an adaptive dead time. With the setting
<(6, 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 together under
address  (see above). Details about the circuit-breaker–monitoring can be found
in the function description, section 2.13, at margin heading “Interrogation of the Circuit
Breaker Ready State”.
If there is a danger of stability problems in the network during a three-pole reclosure
cycle, set address  $'76\Q5HTXHVW to <(6. In this case the voltage of the line
and busbar are checked after a three pole trip and before reclosure to determine if suf-

Siemens siprotec 7SA522 Specifications

General

Brand	Siemens
Model	siprotec 7SA522
Category	Protection Device
Language	English