Transmission equipment is mainly used for the XLPE (cross-linked polyethylene) insulation cable for ultra high voltage power to minimize power loss. The experiment examined the partial discharge characteristics according to the insertion of the bar electrode and needle electrode into the XLPE specimen and the air voids. XLPE insulation cable manufactured by T. company and tungsten electrode material by K. company were used for specimens, by adhering conductive tape on the semi-conductive material of the lower electrode of XLPE specimen with the dimension of 16×40×30 [mm] was used as negative electrode. In order to investigate the PD with φ-q-n of XLPE specimen according to the electrode shape and the size of air voids. we examined the PD by varying the voltage after applying voltage of 3~20 kV on the electrode. Therefore, it was confirmed from the result of PD characteristics of specimen that the larger the air void than the gap between electrode (+) and electrode(-), the larger effect on the discharge when the bar electrode and needle electrode inserted into XLPE, and the closer the distance between the insulation and the needle electrode, the faster insulation breakdown.
