96
9440300990 Rev J
Power System Stabilizer
DECS-250
The logic limiter compares the signal from the washout filter with the logic limiter upper
JJ
and lower
KK
limit
settings. If the counter reaches the set delay time
LL
, the time constant for the washout filter changes from
the normal time constant to the limit time constant. When the signal returns to within the specified limits,
the counter resets and the washout filter time constant changes back to the normal time constant.
Figure 92 illustrates the washout filter and logic limiter.
Figure 92. Washout Filter and Logic Limiter
Output Stage
Prior to connecting the stabilizer output signal to the voltage regulator input, adjustable gain
MM
and upper
NN
and lower
OO
limits are applied. The stabilizer output is connected to the voltage regulator input when the
software switch SSW 10
PP
setting is On. Processing of the stabilizer output signal is illustrated in Figure
93.
Figure 93. Output Stage
Terminal Voltage Limiter
Since the PSS operates by modulating the excitation, it may counteract the voltage regulator’s attempts to
maintain terminal voltage within a tolerance band. To avoid creating an overvoltage condition, the PSS
has a terminal voltage limiter (shown in Figure 92) that reduces the upper output limit to zero when the
SSW 9
Logic Limiter
V
lmt_lo
V
lmt_hi
s T
w5
1 + s T
w5
V
PSS_ULMT
V
PSS_LLMT
V
PSS_ULMT
V
PSS_LLMT
Phase Lead
Block
V
ST
Terminal
Voltage Limiter
P0026-22
12-13-04
Disable
Enable
Содержание DECS-250
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Страница 6: ...iv 9440300990 Rev J Revision History DECS 250 ...
Страница 16: ...xiv 9440300990 Rev J Contents DECS 250 ...
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 ...
Страница 52: ...36 9440300990 Rev J Auxiliary Control DECS 250 ...
Страница 56: ...40 9440300990 Rev J Contact Inputs and Outputs DECS 250 ...
Страница 84: ...68 9440300990 Rev J Limiters DECS 250 ...
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 ...
Страница 198: ...182 9440300990 Rev J Timekeeping DECS 250 ...
Страница 210: ...194 9440300990 Rev J CAN Communication DECS 250 ...
Страница 304: ...288 9440300990 Rev J Maintenance DECS 250 ...
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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