الفهرس 
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Abstract
With the rapid public pressure of a viable alternative to the current
thermal and nuclear convention and also with increasing the demand of
renewable energy, wind generation has been a growing market in the last
couple of decades. Wind turbines are often struck by lightning due to their
special shape, complex construction and the fact that they are usually placed
in isolated locations, mainly at higher altitudes with high resistivity soil. So,
a grounding earthing system is needed to reduce the effect of any fault
current and consequently large potentials that arise on ground surface and
become a threat to human life and damage equipment on site.
A new proposal for the assessment of earthing system location used for
wind turbines is presented. This proposal depends on the simulation of the
electric field as well as the calculation of current density at the ground
surface above the earthing system and distribution inside the soil when the
wind turbine is exposed to over voltage. The electrical potential simulation
around the earthing system of wind turbine using ring earth electrode with
and without auxiliary vertical rods is also studied. Accurate calculations and
simulation of the electric field are prerequisite for the simulation of current
density. The electric field distribution is obtained by calculating the electric
potential in three-dimensional domain surrounding the earthing system and
simulating by using Finite Element Method in MATLAB program. The
boundary conditions satisfy both Dirichlet’s and Neumann’s equations. The
simulated electrodes are energized with one per unit voltage to be available
for different types of applied potential. The resistance of the earthing system
is calculated. This simulation model gives confidence in predicting the