ESS Case / Korea(7)

Seogeochado DC microgrid demonstration project

Project TitleSeogeochado DC microgrid
LocationSeogeocha Island, Jindo-myeon, Jeollanam-do, Republic of Korea
Time Period of ProjectJune 2016 – January 2019
Participating organizations Korea Electric Power Corporation, LG ELECTRIC, Inha University
Key wordsDC, Energy Storage System, Microgrid

1. Project summary (background)

Seogeochado overcame the chronic power shortage by establishing a ‘DC ecosystem’. Street lamps that were often turned off were replaced with DC power light-emitting diode (LED). Home appliances such as TV refrigerators and air conditioners as well as carts that help the elderly walk were converted to DC power. As KEPCO and LS ELECTRI converted all of the existing AC power distribution networks to DC, the wires connecting the power poles also changed from three lines for alternating current (AC) to two lines. The synergy effect of Seogeochado’s ‘DC ecosystem’ is greater when it meets new and renewable energy. Solar power and wind power are typical DC power sources. With this project, a total of 500kW of power facilities, including 200kW of solar power, 100kW of wind power, and 200kW of emergency variable speed generators, will be additionally supplied to Seogeochado Island. In Seogeochado, with the DC microgrid construction, dozens of dryers in the seaweed drying field can be operated 24 hours using only solar and wind energy.


2. Objectives of the project

The project objectives due to the construction of Seogeochado DC Island are as follows:

  • Creation of an energy-independent island through renewable power generation
  • 10% energy efficiency improvement with DC power distribution network
  • DC microgrid business model development


3. Current status & results (outcomes)

  • Consists of wind power generation, solar power generation, ESS, variable speed diesel power generation, power converter, DC distribution line, and DC load, and is connected with the existing AC system by hybrid
  • As the Seogeo-do DC microgrid operating system and operating procedure, the communication protocol is applied to integrate the SCADA system of the living-dwelling driveway and the Seogeo driveway in EMS
  • A web server was built to enable remote system operation and management due to the difficulty of providing emergency support to the island area


4. Barriers & obstacles

In spite of numerous shortcomings, the current power distribution system is AC. This is because DC is difficult to transform. However, with the development of power semiconductor technology, DC can be easily transformed, and the situation has changed. For long-distance transmission, DC also loses less power than AC.


5. Lessons learned & best practices

The synergy effect of Seogeochado’s ‘DC ecosystem’ has grown as it met with new and renewable energy. Solar power and wind power are typical DC power sources. KEPCO plans to export the DC ecosystem model through this project. In Southeast Asia, where there are many islands, there are many regions where electricity penetration is as low as 60%. Energy self-reliance can be greatly increased by constructing a ‘DC microgrid’ that combines renewable energy, an energy storage system (ESS) system, and a DC power distribution network in remote areas where it is difficult to draw electricity.


6. Key regulations, legislations & guidelines

Existing energy law & regulation.

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