Environmental Engineering Reference
In-Depth Information
Table 11.4
List of magnitudes simulated for each fault
Fault code
Magnitude
Notes
M1
M2
M3
M4
B
-7
-3
3
7
Absolute
C
-0.10
-0.05
0.05
0.10
Absolute
D
see Table
11.5
Absolute
E
0 %
50 %
100 %
125 %
Of mean pitch in fault-free case
F
-
-
-
-
Only one magnitude (+90)
Fig. 11.8 Hydraulic blade pitch system structure. The pitch sensor measures, for example, the
actuator stroke x as function of the blade pitch angle b. The pitch controller could be a simple
proportional gain. b
ref
is the set reference pitch angle
Table 11.5
Parameters
for
Faults
Parameters
x
n
rad/s
the
hydraulic
pitch
system
ð
Þ
f
under
different
conditions
No fault (fault-free)
[
15
,
20
]
11.11
0.6
High oil content in the oil (M1)
5.73
0.45
Pump wear (M2)
7.27
0.75
Hydraulic leakage (M3)
3.42
0.9
Pressure drop
3.42
0.9
Pump wear is an irreversible slow process over the years that results in low
pump pressure. As this wear is irreversible, the only possibility to fix it is to
replace the pump which will happen after pump wear reaches certain level.
Meanwhile, the pump will still be operating and the system dynamics is slowly
changing, while the turbine structure should be able to withstand the effects of this
