Abstract
Wind turbines are the largest contributor to renewa
ble energy both in Britain and the
rest of Europe. With a rise in the installed capaci
ty and an increase in offshore wind
energy due to governments green targets by 2020, th
ere has been a large
development in new wind turbines for optimized perf
ormance. The present thesis deals
with the uncertainties in regards to the lightning
phenomenon on wind turbines with
emphasis on the rotor blades. Rotor blades are the
most expensive part to replace in
the event of lightning related damage. The research
presents results based on lightning
data analysis on wind turbines, backed up by finite
element analysis testing of wind
turbine systems. The final chapters include the tes
ting and improving of lightning
protection systems installed on modern day rotor bl
ades.
The first part of the thesis deals with the theoret
ical understanding of the lightning
phenomenon and its effect on wind turbine systems.
The core work of the research
begins with the analysis of lightning data collecte
d over Nysted wind farm and different
wind turbines installed over the world. The data an
alysis helps in identifying the parts of
the wind turbine that are at high risk to lightning
attachment and related damage. The
peak current levels of the lightning strikes seen o
n the wind turbine are compared with
those in modern day lightning standards, and show t
hat historic data in the standards
are not an exact match to the real case scenarios.
The lightning data analysis also
sheds light into the importance of upward initiated
lightning, which will become
important for large wind turbines, especially in th
eir new offshore environment. A full
scale 3D FEA model of a wind turbine, with lightnin
g protection systems installed in its
rotor blades, is subjected to electrical stresses t
o find likely attachment points in
regards to upward initiated lightning, and these re
sults are later compared to those
found in the data analysis.
The second half of the thesis deals with the testin
g of new materials and prototype
blades, to be introduced to reduce their radar cros
s section. The new materials include
a large amount of carbon content which affects the
efficiency of the lightning protection
system. High voltage and high current tests backed
up with finite element analysis
have been performed to find how these new materials
affect the performance of the
lightning protection system. The results indicate t
hat further work needs to be done
before these new materials can be integrated into t
he blade, as they increase the risk
of lightning related damage to the blade.
ble energy both in Britain and the
rest of Europe. With a rise in the installed capaci
ty and an increase in offshore wind
energy due to governments green targets by 2020, th
ere has been a large
development in new wind turbines for optimized perf
ormance. The present thesis deals
with the uncertainties in regards to the lightning
phenomenon on wind turbines with
emphasis on the rotor blades. Rotor blades are the
most expensive part to replace in
the event of lightning related damage. The research
presents results based on lightning
data analysis on wind turbines, backed up by finite
element analysis testing of wind
turbine systems. The final chapters include the tes
ting and improving of lightning
protection systems installed on modern day rotor bl
ades.
The first part of the thesis deals with the theoret
ical understanding of the lightning
phenomenon and its effect on wind turbine systems.
The core work of the research
begins with the analysis of lightning data collecte
d over Nysted wind farm and different
wind turbines installed over the world. The data an
alysis helps in identifying the parts of
the wind turbine that are at high risk to lightning
attachment and related damage. The
peak current levels of the lightning strikes seen o
n the wind turbine are compared with
those in modern day lightning standards, and show t
hat historic data in the standards
are not an exact match to the real case scenarios.
The lightning data analysis also
sheds light into the importance of upward initiated
lightning, which will become
important for large wind turbines, especially in th
eir new offshore environment. A full
scale 3D FEA model of a wind turbine, with lightnin
g protection systems installed in its
rotor blades, is subjected to electrical stresses t
o find likely attachment points in
regards to upward initiated lightning, and these re
sults are later compared to those
found in the data analysis.
The second half of the thesis deals with the testin
g of new materials and prototype
blades, to be introduced to reduce their radar cros
s section. The new materials include
a large amount of carbon content which affects the
efficiency of the lightning protection
system. High voltage and high current tests backed
up with finite element analysis
have been performed to find how these new materials
affect the performance of the
lightning protection system. The results indicate t
hat further work needs to be done
before these new materials can be integrated into t
he blade, as they increase the risk
of lightning related damage to the blade.
| Original language | English |
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| Supervisors/Advisors |
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| Publisher | |
| Publication status | Published - 2010 |