Functional Redundancy in Offshore Wind Turbine Design

1
Functional Redundancy in Offshore Wind Turbine
Design
EOW 2007 - BERLIN
ERIKA ECHAVARRIA
2
Outline

• Motivation
• Functional Redundancy
• Concept FBS modeling
• Example
• Conclusions

3
Motivation going offshore

• Corrective maintenance 2x preventive
  maintenance
• High installation, OM and decommissioning costs
  
• OM is about 25-30 of kWh cost

• Objective
• to increase reliability of the system
• to keep the wind turbine available for operation

Motivation
4
Existing functional redundanciesdesign
methodology
System Knowledge
Existing Functional Redundancies
FR Tool
Criticality of components
Find systematically functional redundancies - FR
- within the system

• Alternative configurations to deal with faults

Functional redundancy
5
What are functional redundancies?
Informational level

• Anemometer Wind speed
• Functional redundancies of Wind Speed from
• Pitch angle
• Yaw angle
• Power output
• Rotor speed
• Or Loads

Physical level
Behavioral level
Functional redundancy
6
How do we find functional redundancies? FBS
modeling
FunctionBehaviorState
f1
b1
function
behavior
f2
b2
b3
f3
State transition
FBS modeling
7
Solution functional redundancies
To Regulate Power output
Pitching Blades
function
behavior
Yawing
To Brake
Applying Mechanical Brake
To Yaw
Functional redundancies example
8
example ROTORFunctional description
KE Kinetic Energy (T) Translational (R)
Rotational EE Electrical Energy
To convert aerodynamic Energy ? EE
To convert KE(T) ? KE(R)
To generate torque
To generate Lift
To convert KE(R) ? EE
To create motion in the direction of lift
FBS modeling example
9
How do we find behaviors?
Attributes ?, ?, blades, etc.
Entity Rotor
Possible states
FBS modeling example
10
How do we find behaviors?
Behavior rotating rotor
Possible states
Knowledge about physical laws and principles ?
d ?/dt
Conditions/relations the rotor rotates only in
one direction
Conclusion only 4 possible states
FBS modeling example
11
How do we find behaviors?
Possible state transitions
s1 rotor is stopped s4 rotor rotates at
constant speed s5 rotor is accelerating s6
rotor decelerating
FBS modeling example
12
FBS model
FBS modeling
13
Conclusions

• There is a systematic way of finding functional
  redundancies
• Functional redundancies
• Increase system reliability
• No extra costs
• FBS modeling
• New approach for wind turbine design
• No need of complete system information
• New approach to deal with faults
• Design for alternative operational configuration
  using existing functional redundancies

Conclusions
14
Thank you for your attention!