Functions
2.22 Circuit Breaker Failure Protection
SIPROTEC, 7SD5, Manual
C53000-G1176-C169-5, Release date 02.2011
408
Figure 2-198
Function diagram of pole discrepancy supervision
2.22.2
Setting Notes
General
The circuit breaker failure protection and its ancillary functions (end fault protection, pole discrepancy supervi-
sion) can only operate if they were set during configuration of the scope of functions (address
139
BREAKER
FAILURE
, setting
Enabled
or
enabled w/ 3I0>
).
Circuit breaker failure protection
The circuit breaker failure protection is switched
ON
or
OFF
at address
3901
FCT BreakerFail
.
The current threshold
I> BF
(address
3902
) should be selected such that the protection will operate with the
smallest expected short-circuit current. A setting of 10 % below the minimum fault current for which circuit
breaker failure protection must operate is recommended. On the other hand, the value should not be set lower
than necessary.
If the circuit breaker failure protection is configured with zero sequence current threshold (address
139
=
enabled w/ 3I0>
), the pickup threshold for the zero sequence current
3I0> BF
(address
3912
) can be set
independently of
I> BF
.
Normally, the circuit breaker failure protection evaluates the current flow criterion as well as the position of the
circuit breaker auxiliary contact(s). If the auxiliary contact(s) status is not available in the device, this criterion
cannot be processed. In this case, set address
3909
Chk BRK CONTACT
to
NO
.
Two-stage circuit breaker failure protection
With two-stage operation, the trip command is repeated after a time delay T1 to the local feeder circuit breaker,
normally to a different set of trip coils of this circuit breaker. A choice can be made whether this trip repetition
shall be 1-pole or 3-pole if the initial feeder protection trip was 1-pole (provided that 1-pole trip is possible). This
choice is made in address
3903
1p-RETRIP (T1)
. Set this parameter to
YES
if the first stage is to trip 1-pole,
otherwise set it to
NO
.
If the circuit breaker does not respond to this trip repetition, the adjacent circuit breakers are tripped after T2,
i.e. the circuit breakers of the busbar or of the concerned busbar section and, if necessary, also the circuit
breaker at the remote end unless the fault has been cleared.
Содержание SIPROTEC
Страница 20: ...Contents SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 20 ...
Страница 351: ...Functions 2 18 Synchronism and Voltage Check optional SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 351 ...
Страница 494: ...Functions 2 27 Command Processing SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 494 ...
Страница 640: ...Technical Data 4 27 Dimensions SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 640 ...
Страница 657: ...Appendix A 2 Terminal Assignments SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 657 7SD5 W ...
Страница 754: ...Appendix A 10 Measured Values SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 754 ...
Страница 756: ...Literature SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 756 ...
Страница 768: ...Glossary SIPROTEC 7SD5 Manual C53000 G1176 C169 5 Release date 02 2011 768 ...