9440300990 Rev J
187
DECS-250
Testing
components at the electromechanical oscillation frequencies. If such components are present, it indicates
that the frequency compensation is less than ideal, or that the machine inertia value is incorrect.
PSS test signal configuration settings are provided on the Time Response screen shown in Figure 160.
Click the RTM Analysis screen’s Time Response button to access this screen.
Signal Input
Signal input selections determine the point in the PSS circuitry where the test signal is applied. Test
points include AVR Summing, PSS Comp Frequency, PSS Electric Power, PSS Derived Speed, Manual
Summing, and var/PF.
A time delay is provided to delay the start of a PSS test after the Time Response screen Start button is
clicked.
Figure 160. Time Response Screen
Test Signal Characteristics
Test signal characteristics (magnitude, offset, frequency, and duration) can be adjusted according to the
type of test signal selected.
Magnitude
The test signal magnitude is expressed as a percentage and excludes the gain of externally-applied
signals.
Offset
A dc offset can be applied to the PSS test signal. The offset is expressed as a per-unit value used in
proper context wherever the test signal is applied. A dc offset cannot be applied to a Step test signal.
Frequency
The test signal frequency can be adjusted as desired for Step and Sine test signals. See
Swept Sine Test
Signal
for information about configuring the frequency attributes of swept sine test signals.
Duration
A duration setting controls the total test duration for Sine and External test signals. For Step test signals,
the duration setting determines the “on” period of the signal. The duration setting does not apply to Swept
Sine signals.
Swept Sine Test Signals
Swept Sine test signals employ a unique set of characteristics that include the sweep style, frequency
step, and start/stop frequencies.
Sweep Type
A Swept Sine test signal can be configured as linear or logarithmic.
Summary of Contents for DECS-250
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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 ...
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