
48
9440300990 Rev J
Protection
DECS-250
Figure 34. Generator Capability Curve vs. 40Q Response
Pickup and Trip
A loss of excitation condition exists when the level of absorbed vars exceeds the loss of excitation (40Q)
threshold
A
for the duration of the 40Q time delay
B
. A time delay setting of zero makes the loss of excitation
element instantaneous with no intentional time delay. If the pickup condition subsides before the time
delay expires, the timer and pickup are reset, no corrective action is taken, and the element is rearmed for
any further occurrences of loss of excitation.
The 40Q threshold is expressed as a percentage of the rated var flow for the machine. Loss of excitation
protection can be enabled and disabled
C
without altering the pickup and time delay settings.
BESTCOMS
Plus
loss of excitation settings are illustrated in Figure 35.
Figure 35. Loss of Excitation Protection Settings
A
Pickup (% of rated vars):
Adjustable from 0 to 150% in 1% increments.
B
Time Delay:
Adjustable from 0 to 300 seconds in 0.1 second increments.
C
Mode:
Select Disabled or Enabled.
Field Protection
BESTCOMSPlus Navigation Path:
Settings Explorer, Protection, Field
HMI Navigation Path:
Settings, Protection, Field
Содержание DECS-250
Страница 2: ......
Страница 6: ...iv 9440300990 Rev J Revision History DECS 250 ...
Страница 16: ...xiv 9440300990 Rev J Contents DECS 250 ...
Страница 20: ...4 9440300990 Rev J Introduction DECS 250 ...
Страница 28: ...12 9440300990 Rev J Power Stage DECS 250 ...
Страница 32: ...16 9440300990 Rev J Voltage and Current Sensing DECS 250 ...
Страница 40: ...24 9440300990 Rev J Synchronizer DECS 250 ...
Страница 52: ...36 9440300990 Rev J Auxiliary Control DECS 250 ...
Страница 56: ...40 9440300990 Rev J Contact Inputs and Outputs DECS 250 ...
Страница 84: ...68 9440300990 Rev J Limiters DECS 250 ...
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 ...
Страница 124: ...108 9440300990 Rev J Stability Tuning DECS 250 ...
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 ...
Страница 198: ...182 9440300990 Rev J Timekeeping DECS 250 ...
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 ...
Страница 351: ......