The first installation of 345kV long-length transmission line between Mikyum and Sungdong substation in Korea

345kV 미금${\sim}$성동변전소간 장거리 지중송전선로 준공

The first 150lkV underground transmission line of Korea was installed between Danginri and Yongsan substation in 1974. Since then, the underground transmission lines of about 720 circuit-km had been installed up to 1995. As the national economy has been enlarged and the population of city has been rapidly increased, the demand of an electric power has been very increased. Therefore the first 345kV long-length transmission line of Korea was installed between Mikyum and Sungdong substation on Jan., 1997. This paper describes the design of the 345kV oil-filled cable and its accessories, the design of the system, the methods of installation, field tests, and the future trends of the underground transmission line in Korea.