Generator condition, Generator stability, Bus condition – Basler Electric DECS-250N User Manual
Page 37: Bus stability
9440500990 Rev D
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DECS-250N
Synchronizer
Generator Condition
A dead generator is recognized by the DECS-250N when the generator voltage decreases below the
dead generator threshold
A
for the duration of the dead generator activation delay
B
.
A failed generator is recognized when the generator voltage or frequency does not meet the established
generator stability criteria for the duration of the failed generator activation delay
C
. Generator stability
parameters are described in Generator Stability.
Generator Stability
Before initiating a breaker closure (tying the generator to a stable or dead bus), the generator voltage
must be stable. Several settings are used to determine generator stability. These settings include pickup
and dropout levels for overvoltage
D
, undervoltage
E
, overfrequency
F
, and under-frequency
G
. Recognition of
generator stability is further controlled by a generator stability activation delay
H
. Breaker closure is not
considered if the voltage conditions are not within the stability pickup and dropout settings for the duration
of the stability activation delay.
Bus Condition
A dead bus is recognized by the DECS-250N when the bus voltage decreases below the dead bus
threshold
I
for the duration of the dead bus activation delay
J
.
A failed bus is recognized when the bus voltage or frequency does not meet the established stability
criteria for the duration of the failed bus activation delay
K
. Bus stability parameters are described in Bus
Stability.
Bus Stability
Before initiating a breaker closure (tying the generator to a live bus), the bus voltage must be stable.
Several settings are used to determine bus stability. These settings include pickup and dropout levels for
overvoltage
L
, undervoltage
M
, overfrequency
N
, and underfrequency
O
. Recognition of bus stability is further
controlled by a bus stability activation delay
P
. Breaker closure is not considered if the voltage conditions
are not within the stability pickup and dropout settings for the duration of the stability activation delay.