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2 Functions
124
7ST6 Manual
E50417-G1176-C251-A3
2.12
Automatic Reclosure Function
This function is optional, i.e. not included in all device variants.
Experience shows that about 85% of the arc faults on overhead contact lines are ex-
tinguished automatically after being tripped by the protection. This means that the line
can be connected again. Reclosure is performed by an automatic reclose function
(AR).
The number and length of the reclosure cycles can be set as required by power
system conditions. The actual reclosure happens after the dead time has expired. If
the fault still exists after automatic reclosure (arc has not disappeared, there is a me-
tallic fault), then the auto reclose function will attempt another reclosure after the re-
peated TRIP command by one of the protection functions. The number of reclosure
attempts can be set. Ideally, the auto reclose function ends with a successful recon-
nection of the line. If the fault is still present after the configured maximum number of
reclosure attempts, the line is definitely disconnected from the power system. The
auto reclose function goes into the blocked state and signals that the last TRIP
command was final.
The auto reclose function can also be started by the thermal overload protection. This
protection prevents thermal overload of the overhead contact line and trips as soon as
a threshold temperature is reached. After cooling off, the line can be reconnected by
means of the auto reclose function.
It is also possible to control the integrated auto reclose function by an external protec-
tion device (e.g. a backup protection). The use of two 7ST6 with auto-reclosure or the
use of one 7ST6 with auto-reclosure and a second protection with its own auto-reclo-
sure are equally possible.
2.12.1 Functional Description
Reclosure is performed by an automatic reclosure circuit (ARC). An example of the
normal time sequence of a double reclosure is shown in the figure below.
Figure 2-37
Timing diagram of a double-shot reclosure with action time (2nd reclosure successful)
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Содержание SIPROTEC 7ST6
Страница 14: ...Contents 14 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 24: ...1 Introduction 24 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 254: ...3 Mounting and Commissioning 254 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 288: ...4 Technical Data 288 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 340: ...A Appendix 340 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 342: ...Literature 342 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 354: ...Index 354 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 355: ...Index 355 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...
Страница 356: ...Index 356 7ST6 Manual E50417 G1176 C251 A3 w w w E l e c t r i c a l P a r t M a n u a l s c o m ...