Jeju 2 (Jindo-Jeju)

The Jeju 2 HVDC project, also known as the Jindo-Jeju HVDC system, is the second high-voltage direct current (HVDC) link connecting Jeju Island to mainland South Korea. This project was completed in 2014 and is owned and operated by Korea Electric Power Corporation (KEPCO).

Technical Specifications

The Jindo-Jeju HVDC system has a transmission capacity of 400 MW and operates at a voltage of ±250 kV. The link spans a total length of 105 km, primarily consisting of submarine cables. The system employs a bipolar configuration with metallic return, utilizing four cables: three high-voltage cables and one medium-voltage cable.

The high-voltage cables use mass-impregnated paper insulation, while the medium-voltage cable uses cross-linked polyethylene (XLPE) insulation. This configuration allows for flexible operating modes, as the third high-voltage cable can be connected in parallel with or instead of any of the other three cables.

Converter Stations

The converter stations for this HVDC link use Line-Commutated Converters (LCC) with a conventional arrangement of a single twelve-pulse bridge per pole.

Cable System

LS Cable & System designed and manufactured the submarine cables for this project. The company developed a state-of-the-art manufacturing facility in Donghae capable of producing a single 105 km long submarine cable without joints. This capability was important for the project's implementation.

Control and Protection System

The HVDC system includes advanced control and protection features. The control system allows operators to adjust transmission power levels and change the direction of power flow. The protection system safeguards against faults in both AC and DC parts of the system.

Cooling System

The project incorporates a valve cooling system (VCS) to dissipate heat from the valve towers and maintain optimal operating temperatures during power transmission.

Significance

The Jeju 2 HVDC project is important for several reasons. It enhances the power supply stability to Jeju Island, which previously faced frequent blackouts due to an inefficient and low-capacity independent electric network. The project supports South Korea's energy policies aimed at increasing energy independence and efficiency. It facilitates the integration of renewable energy sources on Jeju Island, supporting the goal of making Jeju carbon-free and entirely powered by renewable energy by 2030. The HVDC link improves the efficiency of power interconnections and minimizes the risk of outages on the island.

This project represents a significant advancement in South Korea's power transmission infrastructure and plays a key role in supporting the growing electricity demand of Jeju Island, particularly considering its popularity as a tourist destination.