Basler Electric DECS-250N - Manual (Page 44)

28 9440500990 Rev D
Regulation DECS-250N
inactive setpoint at the pre-position value and override the tracking function. A portion of the pre-position
setpoints for var and PF modes are illustrated in Figure 17. (Pre-Position Setpoints for AVR, FCR, and
FVR modes are similar and not shown here.)
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-250N 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.