الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Electricity is an essential requirement for modern society. There are two ways to transport electricity from generating plants to load areas, overhead transmission lines and underground power cables.most distribution networks of medium and low voltages are constructed with power cables rather than overhead transmission lines. Cable lines are also less sensitive to climate and environmental conditions and therefore their reliability with respect to overhead lines is higher Electric insulation is main part of power cables and its quality affects expected life-time. There are factors which effect on the insulation such as partial discharge, impurity, roughness, cavities and space charges will affect cable insulation life-time Main reason of dielectric/insulation breakdown is partial
discharge occurrence inside insulation cavities when electric strength of
cavity is low, applied electric field to cavity can lead to breakdown
inside cavity and finally inside solid insulation. Therefore this kind of
discharges can lead to local breakdown in cable insulation This work calculates the electric field stress inside the voids and
cracks within 132 kV XLPE cable insulation using Finite Element Method (FEM). The effects of void radius, position and length are
studied Partial discharge mechanism inside these defects (voids and cracks) is simulated by using MATLAB/Simulink. The effects of defect radius, position are presented and discussed.