الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Wind energy is the most commonly used of all regenerative resources as it can
produce the greatest amount of energy. Modern wind energy turbines are equipped
with advanced electrical and electronic technological systems. Wind turbines are
often subjected to lightning strokes due to their special shape, tall structure and their
presence in the open air. Besides seriously damaging the blades, lightning results in
accidents to low-voltage and control circuit, wherever breakdowns are frequently
occur in many wind farms worldwide. Such damages are no rarity and represent in
the long run an economic risk for manufacturers and operators. Therefore, more
studies are needed in order to minimize the probability of equipment failure due to
the lightning in order to improve wind farms components performance during
lightning strokes.
In this thesis, wind farm performance under lightning stroke is analyzed.
Effective factors on the generated transient voltage during lightning strokes are
investigated and discussed. A wind farm including generators, tower control systems,
arresters and transformer are modeled at high frequency using ATP/ EMTP package.
Electric field distributions around the wind turbine blades surfaces for different blade
material and different IEC lightning protection techniques are presented and
discussed. A grounding system is one of the most important factors required for
appropriate lightning protection system. A proposed design of grounding systems for
a wind turbine was introduced, which effectively reduced the Ground Potential Rise
(GPR), the voltage distributions at ground surface level and touch potential in the
site. A novel technique for wind turbine components protection used ferromagnetic
rings placed around the wind turbine blade roots is presented and discussed. This
technique was effectively damped the induced overvoltage at control devices and
distribution system. Enhances the protection strategy of the wind farms against
lightning stroke by determines the optimum location of wind turbine is achieved by
using Ant Colony Optimization (ACO) technique.