A new model of GIC flowing in the Japanese power grid for assessing the risks of severe space weather disturbances

Geomagnetically induced current (GIC) is hazardous to the social infrastructures having long-length conductors such as power lines, pipelines, and communication cables. A research team of PSTEP has developed a new numerical model for calculating GIC flowing in the Extra High Voltage (EHV) power transmission lines in Japan to estimate a potential risk of GIC in Japan. Dr. Satoko Nakamura, a researcher at Research Institute for Sustainable Humanosphere, Kyoto University, said, “We hope to contribute to a construction of a disaster prevention system.”

A risk of (GIC) is expected to be high for large magnetic storms caused by solar eruptions. One of the most famous consequences is the collapse of the Hydro-Québec power grid on 13 March 1989 associated with a severe geomagnetic storm. Previously, it has been believed that the occurrence of strong GICs is limited in the high latitude regions. Japan is located at low- and mid-latitudes, and the influence from GIC on the transformer situated in Japanese power grid is small. “It has recently been suggested that the Japanese grid system may not be always safe as previously thought,” said Nakamura.

Japan is surrounded by sea, having complicated ground structures. This makes the distribution of GIC complicated and makes it different from GICs on continents. Nakamura’s calculation will be useful to identify the region where GIC is intensified. Nakamura said, “We became able to estimate GICs in Japanese power grid quantitatively.”

The research result was presented at the SGEPSS fall meeting in Kyoto on 19 October 2017.