In high voltage environment

the existence of micro-defect structure can lead to electric field distortion in insulating materials

and is one of the most important factors that influence the insulation strength of alumina ceramics. For studying the influence of typical defect structures of alumina ceramics on the electric field distribution

a mesoscopic model with defect structures of alumina ceramic is set up

and the influence of the existence of grain size

glass phase and porosity on electric field distribution is s analyzed by using the finite element software analysis. The results show that the influence of grain size on electric field distortion is less

while the existence of glass phase has a great influence on the electric field distortion. The influence of glass phase on electric field distortion is related to grain boundary direction. The bigger the included angle between grain boundary direction and electric field direction

the higher the electric field distortion at the glass phase. Compared with the influence of the grain size and glass phase

the influence of the existence of porosity defect on on the electric field distortion inside the alumina ceramics is highest. Specifically

the maximum electric field due to the porosity in the grain is increased by 46.8%

and that due to porosity at the grain is more than doubled. The influence range of porosity on electric field distortion is higher and on the maximum value of the field strength is lower.