9440300990 Rev J
33
DECS-250
Auxiliary Control
Auxiliary Control
BESTCOMSPlus Navigation Path:
Settings Explorer, Operating Settings, Auxiliary Inputs
HMI Navigation Path:
Settings, Operating Settings, Auxiliary Inputs
The DECS-250 accepts an external analog control signal for auxiliary control of the regulation setpoint.
Auxiliary setpoint control is possible in all regulation modes: AVR, PF, Var, FCR, and FVR. The control
signal can also be used for limiter scaling or power system stabilizer control. Auxiliary control settings are
illustrated in Figure 22.
Auxiliary Control Input Type
A
Either a voltage or current control signal may be used for auxiliary control. Terminals I+ and I– accept a 4
to 20 mAdc signal. Terminals V+ and V– accept a –10 to +10 Vdc signal. An adjacent terminal labeled
GND provides the connection for a recommended cable shield. The input type is selected in
BESTCOMS
Plus
®
.
Auxiliary Control Input Function
B
The analog control input can be used for auxiliary control of the regulation setpoint, as a power system
stabilizer test input, or for limiter scaling.
PSS Test Input
The auxiliary control input can be used for control of the optional power system stabilizer function during
testing and validation. More information is provided in the
Power System Stabilizer
chapter of this manual.
Limiter Scaling
When the auxiliary control input is configured for limiter scaling, the stator current limiter (SCL) and
overexcitation limiter (OEL) low-level values can be automatically adjusted. Automatic adjustment of the
SCL and OEL is based on six parameters: signal and scale for three points. The signal value for each
point represents the accessory input voltage. The scale value defines the limiter low level as a percentage
of rated field current for the OEL and rated stator current for the SCL. For accessory input voltages
between two of the three defined points, the low-level limiter setting is linearly adjusted between the two
scale values. Limiter settings and limiter scaling are discussed in detail in the
Limiters
chapter of this
manual.
Setpoint Limits
Minimum and maximum setpoint limits are observed when the With Limit box is checked.
Auxiliary Control Gains
When a current input type is selected, the input current is converted internally by the DECS-250 into a
voltage signal in the range of –10 to +10 Vdc. The DECS-250 uses the following equation when
converting the applied current into a voltage.
𝑉𝑉
𝑎𝑎𝑎𝑎𝑎𝑎
= (
𝐼𝐼
𝑎𝑎𝑎𝑎𝑎𝑎
−
0.004) ×
�
20.0
0.016
� −
10.0
Equation 6. Input Current to Voltage Signal Conversion
Where: V
aux
is the calculated voltage signal and I
aux
is the applied current in amperes.
For setpoint control, V
aux
is multiplied by the appropriate regulation mode auxiliary gain setting.
If the auxiliary input is unused, all auxiliary control gains should be set to zero.
Содержание DECS-250
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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 ...
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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 ...
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 ...
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Страница 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
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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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