[Agile Electronics Story] Submarine Power Cable Brightly Connecting Land and Islands

[Asia Economy Reporter Ki-min Lee] ‘Agile Electronics Story’ is a corner that keenly examines small pieces of information about electronic and mechanical products and devices. We kindly cover hot new products frequently appearing in advertisements and news, nostalgic products, puzzling products, industry terms, and news with the heart of a beginner.

It has been quite a long time since we entered an era where even islands without a single power plant can have lights on late into the night and sustain daily life.

So, where does that electricity come from? Although solar panels installed in each household are sometimes used, most of the electricity is mainly produced at power plants on the mainland. Typically, the generated electricity is transmitted mainly through transmission towers.

When transmission towers cannot be erected due to distance or strong winds, power cables are buried under the sea to transmit electricity. The cables used in this case are submarine power cables.

Global demand for submarine power cables has been increasing for several years. In this edition of ‘Agile Electronics Story,’ we will take a closer look at submarine power cables.

Tens of Kilometers Long and 50m Production Equipment... Astonishing Submarine Power Cables

AC Submarine Power Cable

<사진=LS전선> → Photo by LS Cable & System

Submarine power cables are cables that transmit high-voltage electricity across seas between continents, or between land and islands. Like other land power cables, submarine power cables are divided into transmission and distribution. Transmission refers to the process of transporting electricity generated at power plants, while distribution means sending electricity through transformers to facilities or homes. Depending on the transmission method, they are classified into alternating current (AC) and direct current (DC). AC submarine cables are mainly used for medium to long distances (under 100 km). DC cables are primarily used for ultra-long-distance power grid connections over 100 km, enabling low-loss power transmission.

The manufacturing process is similar to that of ultra-high voltage cables. First, copper raw material is melted in a furnace and drawn into conductor strands. The drawn conductor strands are made thinner and twisted together with multiple strands to form a bundle. The bundled conductor is then wrapped with an insulator to prevent leakage. The insulator is made of materials such as XLPE, which is polyethylene mixed with organic sulfur compounds. Afterward, the outer part is covered with aluminum or lead (Pb) and then wrapped again with PVC or similar materials. To manufacture submarine power cables, additional steps are added to the ultra-high voltage cable production process. Since a single transmission submarine power cable can extend tens of kilometers in a straight line, a process to draw it out in long lengths is necessary. For this reason, manufacturing equipment about 50 meters long is required. The produced submarine power cable is wound onto a turntable.

▲LS Cable employees are loading ultra-high voltage submarine cables at the Donghae plant. (Provided by LS Cable)

The prepared submarine power cable is loaded onto laying vessels and moved for installation. Prior to this, surveys are conducted to examine the seabed topography, presence of volcanic or seismic zones, and maritime boundaries. In shallow waters, divers and cable laying machines are used to bury the cables, while in deep waters over 30 meters, underwater robots or remotely operated vehicles are deployed. The reason for burying the cables is to prevent damage caused by fishing boats snagging the cables with nets or large fish like sharks biting them, mistaking them for prey. Therefore, in deep waters of several thousand meters where large fish cannot live and fishing does not occur, submarine power cables are installed by simply laying them on the seabed. For long connection distances, cables are joined using connectors.

Market Size Growing Rapidly Amid Global Eco-Friendly Trends

Due to global eco-friendly trends, the submarine power cable market is gradually expanding. The method of sending electricity from existing power facilities without building power plants on islands to preserve the eco-friendly ecosystem is gaining attention. Additionally, submarine power cables are used to directly supply electricity generated from offshore wind farms.

According to the industry, the global submarine power cable market is expected to grow from $4.061 billion in 2016 at an average annual growth rate of 5.89%, reaching $5.83 billion this year. In South Korea, submarine power cable projects are actively underway. Korea Electric Power Corporation recently announced a bid for a 230 billion KRW third ultra-high voltage direct current submarine cable construction project connecting Jeju and Wando.

Worldwide, only a handful of companies such as those in the United States, France, and Japan can manufacture submarine power cables. Among domestic companies, LS Cable & System is active in the market. LS Cable & System entered the submarine power cable market in 2008 and, in February last year, became the first Korean company to enter the Brazilian submarine cable market. They also secured projects worth a total of 500 billion KRW in Taiwan. Furthermore, earlier last month, they won a project worth 100 billion KRW in Bahrain.