94
9440300990 Rev J
Power System Stabilizer
DECS-250
Figure 87. Generator Electrical Power Signal
After high-pass filtering, the electrical power signal is integrated and scaled, combining the generator
inertia constant
O
(2H) with the speed signal. Low-pass filtering within the integrator is controlled by time
constant TI2
P
.
Derived Mechanical Power Signal
The speed deviation signal and integral of electrical power deviation signal are combined to produce a
derived, integral of mechanical power signal.
An adjustable gain stage, Kpe
Q
, establishes the amplitude of the electrical power input used by the PSS
function.
The derived integral of mechanical power signal is then passed through a mechanical-power, low-pass
filter and ramp tracking filter. The low-pass filter is controlled by time constant TI3
R
and provides
attenuation of torsional components appearing in the speed input path. The ramp tracking filter produces
a zero, steady-state error to ramp changes in the integral of electric power input signal. This limits the
stabilizer output variation to very low levels for the mechanical power rates of change that are normally
encountered during operation of utility-scale generators. The ramp tracking filter is controlled by time
constant Tr
S
. An exponent consisting of a numerator
T
and denominator
U
is applied to the mechanical
power filter.
Processing of the derived integral of mechanical power signal is illustrated in Figure 88.
Figure 88. Derived Mechanical Power Signal
Stabilizing Signal Selection
Figure 89 illustrates how software switches SSW 2
V
and SSW 3
W
are used to select the stabilizing signal.
Derived speed deviation is selected as the stabilizing signal when the SSW 2 setting is Derived Speed
and the SSW 3 setting is Derived Frequency/Speed. Washed out speed is selected as the stabilizing
signal when the SSW 2 setting is Frequency and the SSW 3 setting is Derived Frequency/Speed.
Washed out power is selected as the stabilizing signal when the SSW 3 setting is Power. (When the SSW
3 setting is Power, the SSW 2 setting has no effect.)
SSW 1
Disable
Enable
Power
Washed Out
Power
P0026-14
sT
w3
1+ sT
w3
sT
w4
1+ sT
w4
T
l2
/ 2H
1+ sT
l2
PSS Power Input Signal
Σ
Σ
+
+
K
PE
Washed
Out
Speed
Derived
Speed
Deviation
P0026-15
(
)
N
M
L
sT
−
+
3
1
1
N
L
R
sT
sT
+
+
3
1
1
Содержание DECS-250
Страница 2: ......
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 ...
Страница 351: ......