Arcteq AQ G397, Instruction Manual

Page: 156 / 211

Instruction manual – AQ G3x7 Generator protection IED 156 (211
)
Table 3-65: Setting parameters of the overexcitation protection function.
Parameter Setting value, range
and step
Description
Operation Of
Definite time
IEEE
Operating mode selection for the function. Operation can be
either disabled “Off” or definite time or IEEE inverse
characteristics. Default setting is definite time.
Start U/F 80…14 0 % by step of
1 %
Pick up setting of the function. Default setting is 110 %.
Time
multiplier
1 …100 by step of 1 Time multiplier for inverse time characteristics. Default setting
is 10
Min Time
Delay
0.5 … 60s by step of
0.01
Minimum time delay for inverse time characteristics or delay
for the definite time characteristics. Default setting is 10.
Max Time
Delay
300 … 8000s by step
of 0.01
Maximum time delay for inverse time characteristics. Default
setting is 3000.
Cooling time 60 … 8000s by step of
0.01
Reset time delay for inverse time characteristics. Default
setting is 1000.
3.2.25 B
REAKER FAILURE PROTECTION
CBFP (50BF)
After a protection function generates a trip command, it is expected that the circuit breaker
opens and/or the fault current drops below the pre-defined normal level. If not, then an
additional trip command must be generated for all backup circuit breakers to clear the fault. At
the same time, if required, a repeated trip command can be generated to the circuit breaker(s)
which are expected to open. The breaker failure protection function can be applied to perform
this task.
The starting signal of the breaker failure protection function is usually the trip command of any
other protection function defined by the user. Dedicated timers start at the rising edge of the
start signals, one for the backup trip command and one for the repeated trip command,
separately for operation in the individual phases.
During the running time of the timers the function optionally monitors the currents, the closed
state of the circuit breakers or both, according to the user’s choice. When operation is based
on current the set binary inputs indicating the status of the circuit breaker poles have no effect.
If the operation is based on circuit breaker s
tatus the current limit values “Start current Ph” and
“Start current N” have no effect on operation.
The breaker failure protection function resets only if all conditions for faultless state are
fulfilled. If at the end of the running time of the backup timer the currents do not drop below