电缆半导电层介电性能对电场分布的影响

用有限元法研究了电缆内外半导电层电阻率及介电常数对电缆电场分布的影响规律.研究表明,随着内半导电层介电常数的增加,电缆内部的最大场强增加,内屏蔽层的场强明显减小,较高的介电常数会引起电介质内电场分布的畸变,过低的介电常数会使半导电层处场强集中,进而可能引发树枝状放电;随着外半导电层电导率的增加,电缆外护层的场强及电压明显降低,这对减小高压电缆绕组电晕发生的概率有一定的指导意义.

Effect of Cable Semi-Conductive Layer Dielectric Performance on Electric Field

The effect of cable semi-conductive layer resistivity and dielectric constant on electric field distrihution is studied by finite-element method (FEM).The computation results indicate the maximum electric field intensity in the cable increases and electric field intensity in the internal semi-conductive layer re- duces with the increase of the internal semi-conductive layer di- electric constant.Rather larger dielectric constant of the internal semi-conductive layer will cause the electric field distortion in the insulation layer.On the other hand,lesser dielectric constant will cause the electric field concentration in the internal semi- conductive layers and then may bring tree discharge.The results also indicate that the electric field intensity and potential in the external semi-conductive layer sharply reduce with the decrease of the external semi-conductive layer resistivity,which has defi- nite instructing meaning to reduce the corona discharge on the high-voltage cable winding surface.