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2 Functions
178
7ST6 Manual
E50417-G1176-C251-A3
2.18.1.4 Tripping Logic of the Entire Device
TRIP Command
Just like for pickup, a group alarm exists for the device TRIP command.
The alarm
„Relay TRIP“
is an OR combination of
• All trip signals of the individual protection functions
• The TRIP commands output by the control, and
• The TRIP commands output by the CB test function.
General Trip
All trip signals for the protective functions are connected by OR and generate the in-
dication
„Protection TRIP“
. This can be allocated to LED or output relay.
Terminating the
Trip Signal
A trip command once transmitted is stored (see Figure 2-56). At the same time, the
minimum trip command duration
TMin TRIP CMD
is started. This ensures that the
command is transmitted to the circuit breaker for a sufficient amount of time, even if
the function which issued the trip signal drops out quickly. The trip commands can only
be terminated when the last protection function dropped out, i.e. functions no longer
pick up, AND the minimum trip signal duration expired.
A further condition for terminating the trip command is that the circuit breaker is rec-
ognized to be open. The function control of the device checks this by evaluating the
current flow. It assumes that a current of 0.05 In will certainly be undershot with the
circuit breaker open. The figure below shows the logic diagram for this.
Figure 2-56
Storage and termination of the trip command
Reclosure Inter-
locking
When tripping the circuit breaker by a protection function the manual reclosure must
often be blocked until the cause for the protection function operation is found. 7ST6
enables this via the integrated reclosure interlocking.
The interlocking state („LOCKOUT“) is implemented by an RS flipflop which is protect-
ed against auxiliary voltage failure (see Figure 2-57). The RS flipflop is set via binary
input
„>Lockout SET“
(FNo. 385). With the output alarm
„LOCKOUT“
(FNo. 530), if
interconnected correspondingly, a reclosure of the circuitbreaker, e.g. for automatic re-
closure, manual close signal, synchronization, closing via control, can be blocked.
Only once the cause for the protection operation is known, should the interlocking be
reset by a manual reset via binary input
„>Lockout RESET“
(FNo. 386).
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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 ...