Press Release

Press Release

Commencement of voltage fluctuation control tests for large-scale introduction of solar power generation

December 11, 2012
Chubu Electric Power Co.,Inc.

Chubu Electric Power, working in collaboration with Mitsubishi Electric Corporation (President & CEO: Kenichiro Yamanishi; Location: Marunouchi, Chiyoda-ku, Tokyo; below "Mitsubishi Electric"), has installed a prototype system that combines storage batteries and other components with an aim towards controlling voltage fluctuation that is one problem associated with large-scale introduction of solar power generation facilities, and has begun field tests from today.

The output from solar power generation varies greatly with the weather. As a result, large-scale introduction of solar power generation facilities to the distribution system in the future may cause short-cycle fluctuation of the current flowing into distributing substations. There is concern that this may lead to fluctuations in the voltage delivered from the substations.

Chubu Electric Power and Mitsubishi Electric have been jointly conducting research on controlling short-cycle voltage fluctuations. The two companies have created a prototype system that combines a power conditioner and lithium-ion cells, and have installed it at the Shimoze substation (Distributing substation, Shimoze, Iida City, Nagano Prefecture) that is connected to Mega Solar Iida (output: 1,000 kW; started operation in January 2011) and household solar power generation facilities.

As the next step, the prototype system will be used to observe fluctuations in current and voltage in the substation. Methods will then be established to control voltage fluctuations by charging and discharging power from the storage batteries to combat fluctuations that are detected.

Chubu Electric Power will steadily proceed with system stabilization measures that will be required for large-scale adoption of solar power generation in the future, and will actively strive to implement low-carbon power supply.

[Overview of field tests]


December 11, 2012 to November 2015

Test location

Chubu Electric Power Shimoze substation
(Shimoze, Iida City, Nagano Prefecture)

Test facilities

Power conditioner (250 kVA)
Lithium-ion cells (25 kWh)

Test details

Check the effectiveness of the prototype system
Collect technical information
Assess deterioration resistance (life) of lithium-ion cells


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