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Press Release

NEDO Runs Submergence Test on Solar Power System

– Aiming to develop guidelines for ensuring better safety during flood disasters –
December 4,2017
New Energy and Industrial Technology Development Organization (NEDO)
Japan Photovoltaic Energy Association
Okuji-Kensan Co.,Ltd.

For four days, from November 28 to December 1, NEDO, the Japan Photovoltaic Energy Association (JPEA), and Okuji-Kensan Co., Ltd. conducted a submergence test of a solar power system in Hokuto City, Yamanashi Prefecture. The test was a demonstration aiming to assess the risks of electric shock from the system, and was part of series of demonstration tests to ensure better safety of the solar power system.

Based on the results from the test, the participants will seek to develop guidelines to ensure safety during inspection and removal of the solar power system during floods, as well as guidelines for inspection equipment and solutions.

Appearance of the solar power system devices Figure 1 Solar power system devices used
in the submergence test
Scene of a test scenarioFigure 2 Test scenario (an example)

1.Outline

Due to the launch of the feed-in tariff scheme (FIT)*1 in July 2012, Japan has increased its implementation of solar power systems. However, there have been some instances where these systems were submerged due to natural disasters, such as typhoons or heavy rain. As the submerged system’s insulation may perform poorly, there is a danger of electric shock when approaching or touching the equipment. The Japan Photovoltaic Energy Association (JPEA) has issued advice on how to deal with the situation if the solar system is damaged by submergence.*2

NEDO, JPEA, and Okuji-Kensan Co., Ltd. conducted a submergence test of a solar power system in Hokuto City, Yamanashi Prefecture, in order to assess the risks of electric shock from the system during episodes of water damage. The test was part of NEDO's project for the safety, titled "Project for Improvement of Efficiency and Development of Operation and Maintenance Technology of Photovoltaic Power Generation Systems/Demonstrating the Theory for the Safety of Photovoltaic Power Generation Systems".

The test was conducted on the assumption that the solar system will continue generating electricity after being submerged. By submerging the solar system in a closed pond, the team was able to conduct quantitative investigations, including assessing the risk of electric shock by measuring the level of electrical leakage from the system into the water, and observing the overall situation after the submergence had taken place.

Based on the results from the test, the participants will seek to develop guidelines to ensure safety during inspection and removal of the solar power system during episodes of water damage, as well as guidelines for inspection equipment and solutions, by the end of FY2017. In addition to these efforts, they will continue to raise awareness to prevent electric shock accidents.

  • ●Test period: November 28, 2017 (Tuesday) to December 1, 2017 (Friday)
  • ●Test place: Natsuaki/Tsukagawa area, Nagasaka-cho, Hokuto city, Yamanashi Prefecture (a regulated test pond next to the Hokuto Site Solar Power Plant)
  • ●Test contents: Assembled the solar power system, including a solar cell module, a connection box and a power conditioner, to imitate the actual use (photovoltaic array), in order to observe electricity leakage and system’s condition after submerging the system in the test pond. Prior to the test, a bench-scale test was conducted by measuring the level of electricity leakage after submerging pieces of equipment in a water tank, such as a solar cell module and a connection box.

【Glossary】

*1 Feed-in Tariff Scheme (FIT)
Act on Special Measures Concerning Procurement of Electricity from Renewable Energy Sources by Electricity Utilities (Act No. 108 of August 30, 2011)
Final revision of Act No. 59 of June 3, 2016
*2 Disseminating information on how to handle a situation when a solar system is damaged after being submerged.

2.For more information, please contact:

NEDO New Energy Technology Department
Contact Persons: Morita, Yasuda Tel: +81-44-520-5277­

Japan Photovoltaic Energy Association (JPEA)
Contact Person: Inoue Tel: +81-3-6268-8544­