The HVDC Haenam–Cheju is a 101 kilometers long HVDC submarine cable connection between the South Korean Mainland and the island of Jeju in South Korea, which went into service in 1996. The connection consists of two monopolar 180kV-lines with a maximum transmission power of 300 megawatts. The line runs from the Haenam converter station situated at (34°22′03″N126°35′34″E) to Jeju converter station at (33°32′06″N126°35′44″E) and has no overhead line sections. The first 5 kilometres on Korean Mainland are underground, the rest of the cable is laid partially buried in the sea. As the station on Jeju is close to the sea, all equipment is encapsulated in order to prevent corrosion from sea salt. The system is designed to take over the full power supply of Jeju and is therefore equipped with synchronous compensators delivering the require reactive power when there is no generation unit at Jeju in work.