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2nd PhD Seminar on Wind Energy in Europe
Risø National Laboratory, 4-5 October 2006
Aspects of Relevance in Offshore
Wind Farm Reliability
Assessment
Nicola Barberis Negra
[email protected]
Outline
• Introduction to Reliability
• Why Wind Generation into Reliability
• Example of Evaluation
• Conclusions
• Questions
5th October 2006
Nicola Barberis Negra - [email protected]
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Outline
• Introduction to Reliability
• Why Wind Generation into Reliability
• Example of Evaluation
• Conclusions
• Questions
5th October 2006
Nicola Barberis Negra - [email protected]
3
Introduction - Definition
What is Reliability?
“Overall ability of the system to perform its function
adequately, for the period of time considered, under
the operation conditions intended”
Reliability in Power System
• Operation
• Planning
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Introduction – Structure of Reliability
Generation
facilities
Hierarchical Level I
Transmission
facilities
Hierarchical Level II
Distribution
facilities
Hierarchical Level III
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(HLI)
(HLII)
(HLIII)
Generating Units and Load
HLI + Transmission System
HLII + Distribution System
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Introduction – Structure of Reliability
Generation
facilities
Hierarchical Level I
Transmission
facilities
Hierarchical Level II
Distribution
facilities
Hierarchical Level III
(HLI)
(HLII)
(HLIII)
Generating Units and Load
HLI + Transmission System
HLII + Distribution System
Two new aspects
• Distributed Generation
• Private Suppliers
5th October 2006
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Introduction – Evaluation Methods
• Deterministic solutions
– First used approaches
– No uncertainty can be included
• Probabilistic methods
– Analytical models or simulations
– Uncertainty may be included
– Broad range of studies
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Outline
• Introduction to Reliability
• Why Wind Generation into Reliability
• Example of Evaluation
• Conclusions
• Questions
5th October 2006
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Why Wind Energy
• New structure of power systems
– Increase of installed capacity (e.g. Germany)
– Increase of wind energy penetration (e.g. Denmark)
• Evolution of Installations
– Onshore installations (smaller and distributed)
– Offshore installations (larger and concentrated)
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Why Wind Energy - Aspects of Relevance
1. Simulation of wind speed (WS)
2. Wake effects
3. Wind turbine technology
4. Offshore environment
5. Different wind speed in the installation site
6. Power collection grid in the wind park
7. Correlation of output power for different wind farms
8. Grid connection configuration
9. Hub height variations
5th October 2006
Nicola Barberis Negra - [email protected]
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Outline
• Introduction to Reliability
• Why Wind Generation into Reliability
• Example of Evaluation
• Conclusions
• Questions
5th October 2006
Nicola Barberis Negra - [email protected]
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Example – Monte Carlo Simulation
“Estimation of a-posteriori reliability indices by
simulating the actual random behaviour of the
system for the period intended”
Main steps:
1. Simulation and system definition
2. Components availability in each sample
3. Synthetic Wind speed time series in each sample
4. Wind farm output power in each sample
5. Wind farm index evaluation
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Example – Simulation Definition
Sequential Monte Carlo simulation
• Period of 1 year with hourly step (8760 hours)
• Relevant aspects included
– Random wind speed time series
– Wind turbine technology
– Power collection grid in the wind park
– Grid connection configuration
– Offshore environment
5th October 2006
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Example – System Definition
Wind farm layout
Nr.
Failure rate
MTTR
Wind turbine (Vestas V90)
25
1,5 1/y
490 h/y
Cable (~700 m)
25
0,015 1/y/km
1440 h/y
3
0,015 1/y/km
1440 h/y
Connector (~10 km)
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Component data
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Example – Simulation Procedure
2. Component availability
4. Wind Farm output power
5. Wind Farm Indices
3. Wind speed time series
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Example – Results
Index
Value
Unit
1. IWP
75
MW
2. IWE
657000,00
MWh
3. EAWE
281657,91
MWh
4. EGWEWTF
260479,91
MWh
5. EGWE
258344,21
MWh
6. CF
0,3932
-
7. GR
0,9237
-
Simulation time
10722
s
Result accuracy
0,2
%
Nr of Samples
485
-
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1. IWP =Installed Wind Power
2. IWE = Installed Wind Energy
3. EAWE = Expected Available
Wind Energy
4. EGWEWTF = EAWE With WT
Failure
5. EGWE = Expected Generated
Wind Energy
6. CF = Capacity Factor
7. GR = Generation Ratio
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Example – Comments
Index
Value
Unit
1. IWP
75
MW
2. IWE
657000,00
MWh
3. EAWE
281657,91
MWh
4. EGWEWTF
260479,91
MWh
5. EGWE
258344,21
MWh
6. CF
0,3932
-
7. GR
0,9237
-
Simulation time
10722
s
Result accuracy
0,2
%
Nr of Samples
485
-
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• Different aspects of wind
farm production
• Relevance of including
component failures (indices
3 to 5)
• CF reasonable for offshore
installations
• Huge computational time
• Possibility of plotting index
distribution functions
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Outline
• Introduction to Reliability
• Why Wind Generation into Reliability
• Example of Evaluation
• Conclusions
• Questions
5th October 2006
Nicola Barberis Negra - [email protected]
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Conclusions
• Relevance of including wind generation into power
system reliability assessment
• Importance of 9 aspects for the problem
• Monte Carlo simulation is a powerful tool, but it
needs some optimizations
• Future developments
– Inclusion of all missed aspects
– Improvement of the simulation
– HLI and HLII analysis
5th October 2006
Nicola Barberis Negra - [email protected]
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Outline
• Introduction to Reliability
• Why Wind Generation into Reliability
• Example of Evaluation
• Conclusions
• Questions
5th October 2006
Nicola Barberis Negra - [email protected]
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