In this study, the partial discharge degradation properties for 2-core PVC cable(2 cores × 1.5 mm2 cross section, length of 10 cm, 20 cm, 30 cm) following immersion with the salt water that the 2%, 4%, 8% of NaCl is dissolved in 100 g of distilled water for 48 and 96 hours has been measured. The results of this study are as follows. When the degradation time in salt water of 2% NaCl is 48 hours, it found that the number of partial discharge increased as about 40 pps, 50 pps, 90 pps with increasing the length of cable to 10 cm, 20 cm, 30 cm. In case the concentration and degradation time is same, the inception and extinction voltage decreased with increasing the length of cable. When the degradation time in salt water is 96 hours and the length of cable is 20 cm, it found that the number of partial discharge decreased as 3,000 pps, 500 pps, 100 pps with increasing the concentration of NaCl to 2%, 4%, 8%.

In this study, the characteristics of partial discharge was measured for the four core silicone cable (0.6/1.0 kV, 1.0 SQ × 4 C) with insulated part of 15 cm and conductor of 1cm. The following results have been confirmed as a result of this study. When the first line of cable is connected to the positive electrode and the second, third line of cable is connected to the negative electrode, it found that the inception voltage and extinction voltage decreased with increasing the line of negative electrode, and the partial discharge charge quantity(Q) increases, while the number of discharge occurrence has decreased. The inception voltage and extinction voltage of partial discharge has decreased with increasing the degradation rate in the 33%, 67%, 100%. Also, it confirmed that the partial discharge charge quantity(Q) and the number of discharge occurrence has decreased.