Application of 77 kV Overhead Insulated Cables

In this paper, we examine and report on the potential and effects of enlarging cable sizes and installing joint boxes on utility poles in the overhead cable laying method for 77 kV solidinsulated cables. Traditionally, the underground cable laying method has been mainly adopted, however, in Japan, overhead cable laying method is commonly adopted for 6.6 kV distribution cable. For 77 kV transmission system, overhead cable laying method has been rarely used and could be applicable only for relatively small cable sizes. This study clarifies the technical challenges and facility configuration related to enlarging the cable size for 77 kV in the overhead cable laying method, as well as installing joint boxes on utility poles.