28
9440300990 Rev J
Regulation
DECS-250
Figure 17. Pre-Position Setpoints
A
Setpoint:
Range of adjustment is based on the generator ratings and limited by the Var Minimum and
Var Maximum settings.
B
Mode
: Select Release or Maintain
Transient Boost
The transient excitation boosting function improves response to successive faults by providing increased
excitation support. When a simultaneous line current increase and line voltage decrease occurs, the
DECS-250 compensates by elevating the voltage setpoint above the nominal setpoint. When the line
voltage recovers, the voltage setpoint is restored to the nominal value.
Fault detection is controlled by a voltage threshold
A
setting, a current threshold
B
setting, and a duration
C
setting. Fault voltage threshold is expressed as a percentage of the AVR setpoint and fault current
threshold is expressed as a percentage of the rated field current. The duration setting determines how
long a fault condition is tolerated before the setpoint is adjusted.
Setpoint adjustment is controlled by a voltage setpoint boosting level
D
, a clearing voltage threshold
E
, and
a clearing voltage delay
F
. The setpoint boosting level is expressed as a percentage above the AVR
setpoint. Transient boost is disabled once the line voltage recovers above the clearing voltage threshold.
The clearing voltage threshold is expressed as a percentage below the AVR setpoint. The clearing
voltage delay determines how long the line voltage must exceed the clearing voltage threshold before
setpoint adjustment is terminated.
Figure 18. Transient Boost Settings
A
Fault Voltage Threshold (%):
Adjustable from 0.0 to 100.0%, in 0.1% increments.
B
Fault Current Threshold (%):
Adjustable from 0.0 to 400.0%, in 0.1% increments.
C
Minimum Fault Duration (ms):
Adjustable from 0 to 1,000 ms, in 1 ms increments.
D
Voltage Setpoint Boosting Level (%):
Adjustable from 0.0 to 100.0%, in 0.1% increments.
E
Clearing Voltage Threshold (%):
Adjustable from 0.0 to 50.0%, in 0.1% increments.
F
Clearing Voltage Delay (ms):
Adjustable from 0 to 1,000 ms, in increments of 1 ms.
Operation with Paralleled Generators
BESTCOMSPlus Navigation Path:
Settings Explorer, Operating Settings, Parallel/LineDrop
Compensation
HMI Navigation Path:
Settings, Operating Settings, Parallel/LineDrop Compensation
Summary of Contents for DECS-250
Page 2: ......
Page 6: ...iv 9440300990 Rev J Revision History DECS 250 ...
Page 16: ...xiv 9440300990 Rev J Contents DECS 250 ...
Page 20: ...4 9440300990 Rev J Introduction DECS 250 ...
Page 28: ...12 9440300990 Rev J Power Stage DECS 250 ...
Page 32: ...16 9440300990 Rev J Voltage and Current Sensing DECS 250 ...
Page 40: ...24 9440300990 Rev J Synchronizer DECS 250 ...
Page 52: ...36 9440300990 Rev J Auxiliary Control DECS 250 ...
Page 56: ...40 9440300990 Rev J Contact Inputs and Outputs DECS 250 ...
Page 84: ...68 9440300990 Rev J Limiters DECS 250 ...
Page 114: ...98 9440300990 Rev J Power System Stabilizer DECS 250 Figure 96 PSS Parameter Settings ...
Page 124: ...108 9440300990 Rev J Stability Tuning DECS 250 ...
Page 126: ...110 9440300990 Rev J Mounting DECS 250 Figure 103 Overall and Projection Mounting Dimensions ...
Page 127: ...9440300990 Rev J 111 DECS 250 Mounting Figure 104 DECS 250 Escutcheon Plate Dimensions ...
Page 198: ...182 9440300990 Rev J Timekeeping DECS 250 ...
Page 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
Page 304: ...288 9440300990 Rev J Maintenance DECS 250 ...
Page 316: ...300 9440300990 Rev J Specifications DECS 250 ...
Page 334: ...318 9440300990 Rev J Analog Expansion Module DECS 250 ...
Page 351: ......