Basler DECS-200 User Manual

DECS-200 Functional Description 3-13
Underexcitation Limiter
Underexcitation limiting (UEL) operates in all modes except FCR mode. UEL senses the leading var
output of the generator and limits any further decrease in excitation to prevent loss of synchronization and
end-iron heating during parallel operation. In FCR mode, the DECS-200 announces that all conditions for
UEL are fulfilled. The reactive power level is selected at zero active power and the UEL limiting curve is
calculated based on this value and the generator voltage and current rating. Typical leading kvar curves
and a user-selected, five-point curve are shown in 3-9.
45.0k
37.5k
30.0k
22.5k
15.0k
7.5k
0.0
Reactive Power Absorb (var) x 1000
45.0k37.5k30.0k22.5k15.0k7.5k0.0
Real Power Generate (W) x 1000
D2851-25
06-28-05
Figure 3-9. Custom Five-Point Curve
When the system is limiting underexcitation, a UEL annunciation occurs. Underexcitation is annunciated
on the front panel Metering screen and may be assigned to a programmable output relay for external
annunciation.
Stator Current Limiting
The stator current limiter (SCL) senses the level of stator current and limits it to prevent stator
overheating. The SCL operates in all modes except FCR. In FCR mode, the DECS-200 only announces
that a stator overcurrent condition exists; it does not provide current limiting.
Two SCL current levels are provided: high and low (see Figure 3-10). The generator can operate
continuously at the low SCL level and for a programmed time at the high SCL level.
TIME IN SECONDS
High
Current
Time
Continuous
P0013-19
11-10-04
0-60 s
Low
Current
Level
0-66,000 Aac
High
Current
Level
0-66,000 Aac
STATOR CURRENT
Figure 3-10. Stator Current Limiting

Basler DECS-200 Specifications

General

Brand	Basler
Model	DECS-200
Category	Controller
Language	English