Siemens SIPROTEC 7SJ61, Руководство пользователя, Страница: 165 / 454

Functions
2.11 Automatic Reclosing System 79
SIPROTEC, 7SJ61, Manual
C53000-G1140-C210-1, Release date 02.2008 165
Action Time
The action time (address
7117
) monitors the time between a device pickup and the trip command of a protec-
tive function configured as starter. The action time is launched when pickup of any function is detected, which
is set as source of the automatic reclosure program. Protection functions which are set to
Alarm Only
or
which in principle should not start a reclosing program do not trigger the action time.
If a protective function configured as starter initiates a trip command during the action time, the automatic re-
closure program is started. Trip commands of a protective function configured as starter occurring in the time
between expiration of the action time and dropout of the device pickup cause the dynamic blocking of the au-
tomatic reclosing program. Trip commands of protective functions which are not configured as starter do not
affect the action time.
If the automatic reclosure program interacts with an external protection device, the general device pickup for
starting the operating time is communicated to the automatic reclosing program via binary input 2711
„>79
Start“
.
Delay of Dead Time Start
After start of the auto-reclose function, the dead time start can be delayed by pickup of the binary input
message 2754
„>79 DT St.Delay“
. The dead time is not initiated as long as the binary input is active. Start
occurs only on cleared binary input. The delay of the dead time start can be monitored via parameter
7118 T
DEAD DELAY
. If the time elapses and the binary input is still active, the
Automatic Reclosing System 79
changes to the status of the dynamic blocking via (2785
„79 DynBlock“
). The maximum time delay of the
dead time start is logged by message 2753
„79 DT delay ex.“
.
Reclosing Programs
Depending on the type of fault, two different reclosing programs can be used. Here the following applies:
• The single phase fault ( ground fault) reclosing program applies if all fault protection functions that initiate
automatic reclosure detected a phase-to-ground fault. The following conditions must apply: only one phase,
only one phase and ground or only ground have picked up. This program can also be started via a binary
input.
• The multiple phase fault ( phase fault) reclosing program applies to all other cases. That is, when elements
associated with two or more phases pick up, with or without the pickup of ground elements, such as negative
sequence elements. This program can be started via a binary input as well.
The reclosure program evaluates only elements during pick up as elements dropping out may corrupt the result
if they drop out at different times when opening the circuit breaker. Therefore, the ground fault reclosure
program is executed only when the elements associated with one particular phase pick up until the circuit
breaker is opened; all others conditions will initiate the phase fault program.
For each of the programs, up to 9 reclosing attempts can be separately programmed. The first four reclosing
attempts can be set differently for each of the two reclosing programs. The fifth and preceding automatic reclo-
sures will correspond to the fourth dead time.
Reclosing Before Selectivity
For the automatic reclosure sequence to be successful, faults on any part of the line must be cleared from the
feeding line end(s) within the same – shortest possible – time. Usually, therefore, an instantaneous protection
element is set to operate before an automatic reclosure. Fast fault termination has thus priority over selectivity
aspects as the reclosing action aims at maintaining normal system operation. For this purpose all protective
functions which can initiate the automatic reclosure function are set in such manner that they may trip instan-
taneously or with a very small time delay before auto-reclosure.
With the final reclosing attempt, i.e. when no automatic reclosing is expected, protection is to trip with delay
according to the grading coordination chart of the system, since selectivity has priority.For details see also in-
formation at margin heading "Interaction with the Automatic Reclosing Function" which can be found with the