9440300990 Rev J
61
DECS-250
Limiters
Figure 47. Takeover OEL Settings
A
Takeover OEL Low Level:
Adjustable from 0 to 15 Adc in increments of 0.01 Adc.
B
Takeover OEL High Level:
Adjustable range varies depending on value of
Low Level
setting.
C
Takeover OEL Time Dial: Adjustable from 0.1 to 20 in increments of 0.1.
D
Reset Method:
Select Inverse, Integrating, or Instantaneous.
E
Reset Coefficient:
Adjustable from 0.01 to 100 in increments of 0.01.
F
Takeover OEL curve.
G
Curve display selections/legend.
Underexcitation Limiter
BESTCOMSPlus Navigation Path:
Settings Explorer, Operating Settings, Limiters, UEL
HMI Navigation Path:
Settings, Operating Settings, Limiters, UEL
Operating a generator in an underexcited condition can cause the stator end iron to overheat. Extreme
underexcitation may lead to a loss of synchronism. The underexcitation limiter (UEL) senses the leading
var level of the generator and limits decreases in excitation to limit end-iron heating. When enabled
A
, the
UEL operates in all regulation modes. UEL behavior in manual mode can be configured to limit excitation
or issue an alarm. This behavior is configured in BESTlogic
Plus
.
Note
For UEL to operate, the PARALLEL_EN_LM logic block must be set
true in BESTlogic
Plus
programmable logic.
UEL settings are illustrated in Figure 48 and Figure 49.
Underexcitation limiting is implemented through an internally-generated UEL curve or a user-defined UEL
curve
B
. The internally-generated curve is based on the desired reactive power limit at zero real power with
respect to the generator voltage and current rating. The absorbed reactive power axis of the curve on the
UEL Custom Curve screen can be tailored
C
for your application.
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Страница 108: ...92 9440300990 Rev J Power System Stabilizer DECS 250 Figure 85 PSS Function Blocks and Software Switches ...
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Страница 127: ...9440300990 Rev J 111 DECS 250 Mounting Figure 104 DECS 250 Escutcheon Plate Dimensions ...
Страница 128: ...112 9440300990 Rev J Mounting DECS 250 Figure 105 Panel Cutting and Drilling Dimensions for DECS 250 Panel Mounting ...
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