Abstract
Now the distribution cables are often used as armature winding in high voltage motor. The effect of cable semi-conductive layer dielectric performance on electric field distribution was studied by finite-element method (FEM). Then the probability of corona discharge in the winding cables was analyzed. The computed results indicate the maximum electric field intensity in the cable increases and electric field intensity in the internal semi-conductive layer reduces with the increase of the internal semi-conductive layer dielectric constant. In other words, rather large value of the internal semi-conductive layer dielectric constant will cause the electric field distortion in the insulation layer. On the other hand, lesser dielectric constant value 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 provides theoretic foundation for reducing the corona discharge on the high-voltage cable surface. Meanwhile, the research indicates near the outlet of stator slot and bad grounding spot the corona discharge will first occur.
