52
9440300990 Rev J
Protection
DECS-250
Figure 38. Exciter Diode Monitor Protection Settings
A
EDM Pole Ratio
: Adjustable from 0 to 10 in 0.01 increments.
B
Open Diode Pickup Level (%)
: Adjustable from 0 to 100% in 0.1% increments.
C
Shorted Diode Pickup Level (%)
: Adjustable from 0 to 100% in 0.1% increments.
D
Open Diode Delay (s)
: Adjustable from 10 to 60 seconds in 0.1 second increments.
E
Shorted Diode Delay (s)
: Adjustable from 5 to 30 seconds in 0.1 second increments.
F
Disable Level (%)
: Adjustable from 0 to 100% in 0.1% increments.
G
Mode
: Select Disabled or Enabled.
Setting the Pickup Level—Number of Generator Poles Unknown
The DECS-250 can detect shorted diode conditions when the number of generator poles is not known. To
provide this protection, disable open diode protection, set the pole ratio at zero, and enable shorted diode
protection. Multiply the maximum EDM ripple level, obtained under
Finding the Maximum Field Ripple
Current
, by 30. The multiplier can be varied between 20 and 40 to increase or decrease the pickup
margin. However, reducing the multiplier could result in nuisance shorted diode indications.
Testing the EDM Settings
Start the generator from rest and increase the speed and voltage to the rated value. Load the machine to
its rating and confirm that no failed diode annunciations occur. All of the EDM setup guidelines presented
here assume that the exciter diodes were not opened or shorted at the time of setup and testing.
Power Input Failure
A power input failure condition exists when any one of the following occurs:
1-phase operating power
When operating power decreases below 50 Vac, a power input failure condition exists.
3-phase operating power
•
All three phases of operating power decrease below 50 Vac
•
One or more phases of operating power decreases below 10 Vac
•
A phase-to-phase voltage imbalance greater than 20% exists at the operating power input
The DECS-250 settings must be properly set to match the active operating power configuration. For
example, if the DECS-250 settings reflect a 3-phase power configuration but the actual operating power
configuration is 1-phase then the DECS-250 will interpret the one phase as an imbalance and set an
alarm/trip. For more information on 1- and 3-phase operating power settings see
Configuration
and
Specifications
.
Power input failure protection can be used for PMG applications, shunt-, or PMG-powered systems. This
protection is only active in
Start
mode and after soft start. A time delay setting
A
delays power input failure
annunciations to accommodate transient reductions/imbalances in the operating power input voltage.
Power input failure protection can be enabled and disabled
B
without altering the time delay setting. The
selected power input configuration
C
is shown as a read-only value. Power input failure pickup and trip
Содержание DECS-250
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Страница 20: ...4 9440300990 Rev J Introduction DECS 250 ...
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Страница 40: ...24 9440300990 Rev J Synchronizer DECS 250 ...
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Страница 108: ...92 9440300990 Rev J Power System Stabilizer DECS 250 Figure 85 PSS Function Blocks and Software Switches ...
Страница 114: ...98 9440300990 Rev J Power System Stabilizer DECS 250 Figure 96 PSS Parameter Settings ...
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Страница 126: ...110 9440300990 Rev J Mounting DECS 250 Figure 103 Overall and Projection Mounting Dimensions ...
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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Страница 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
Страница 304: ...288 9440300990 Rev J Maintenance DECS 250 ...
Страница 316: ...300 9440300990 Rev J Specifications DECS 250 ...
Страница 334: ...318 9440300990 Rev J Analog Expansion Module DECS 250 ...
Страница 341: ...9440300990 Rev J 325 DECS 250 Contact Expansion Module Figure 188 CEM 2020 Input Contact and Output Contact Terminals ...
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