Improving the prediction model of Spanish power gridʼs vulnerability in solar storms
In September 1859, a big sun burst caused the most violent geomagnetic storm so far -the Carrignton Event- which destroyed the telegraph systems of that time. Nowadays, satellites, electric lines, transport, communication and positioning systems are some of the technological resources that could stop functioning due the impact of geomagnetic storms on Earth.
Now, a new study is improving predictions of the vulnerability in the Spanish network of electric transport, according to an article published in the journal Space Weather, by the experts Àlex Marcuello, Pilar Queralt, Juanjo Ledo, from the Geomodels Research Institute of the University of Barcelona; Joan Miquel Torta and Santiago Marsal (Observatori de lʼEbre - CSIC and URL) and Joan Campanyà, who holds a doctorate from the UB and is member of the Trinity College Dublin (Ireland). The new research study has been distinguished as a research announcement in the EOS newsletter of the American Geophysical Union (AGU), within the area of geology and geophysics.
In September 1859, a big sun burst caused the most violent geomagnetic storm so far -the Carrignton Event- which destroyed the telegraph systems of that time. Nowadays, satellites, electric lines, transport, communication and positioning systems are some of the technological resources that could stop functioning due the impact of geomagnetic storms on Earth.
Now, a new study is improving predictions of the vulnerability in the Spanish network of electric transport, according to an article published in the journal Space Weather, by the experts Àlex Marcuello, Pilar Queralt, Juanjo Ledo, from the Geomodels Research Institute of the University of Barcelona; Joan Miquel Torta and Santiago Marsal (Observatori de lʼEbre - CSIC and URL) and Joan Campanyà, who holds a doctorate from the UB and is member of the Trinity College Dublin (Ireland). The new research study has been distinguished as a research announcement in the EOS newsletter of the American Geophysical Union (AGU), within the area of geology and geophysics.
From polar auroras to technology failure
Apart from the beauty of auroras in polar latitudes, the disturbances of Earthʼs magnetic field caused by the solar cycle can generate huge economic losses in different productive sectors. When the solar wind, carrying particles, interacts with the Earthʼs magnetic field, a geomagnetic storm takes place. This storm can generate Geomagnetically Induced Currents (GIC) in the subsoil, which are dangerous to electrical networks and transport systems (oil pipelines, gas pipelines, railway lines, etc.).
These low-frequency currents, which behave as continuous currents, depend on the regionʼs geoelectrical structure, that is, the regional geology, and on the rocksʼ electric conductivity. Regarding the electrical lines, GIC couple with the distribution network through the transformerʼs earth dams.
According to Àlex Marcuello, lecturer from the Department of Earth and Ocean Dynamics of the University of Barcelona, “the applied methodology in this new study allows a simulation of different situations for the network, according to different magnetic storm conditions. Therefore, modeling can estimate the highest values of GIC for different substations, finding out their effect in different elements of the grid -connected or not- and identifying the most vulnerable ones”.
Improving predictions with the study of electric conductivity
This scientific article, with Joan Miquel Torta as its first author, sets as a study model an electricity substation in Vandellòs, Tarragona. To study the vulnerability of the electric grid, the study analyzes the comprehensive elements of the grid and its length, apart from the geoelectrical structure of the subsoil using in situ measurements in the territory.
“In general, the most vulnerable high voltage lines are the ones with voltages higher than 200 kV” says Àlex Marcuello. “The most GIC-sensitive components are the transformers in the substations. These GIC cause a half-cycle saturation in the nucleus of the transformers, and its consequence is triple: the transformer warms up and can even burn, the current and voltage stop being sinusoidal (50Hz) and become unstable, and last, the gridʼs inductive power increases. As a final result of the three situations, a partial or total blackout can take place”.
A more realistic diagnosis on the countryʼs power grid
The study published in the journal Space Weather creates a prediction model which is one of the most realistic ones so far, based on simplified approaches. In this context, the experts of the Geomodels Research Institute -with its head office in the Faculty of Earth Sciences of the UB- have characterized the conductivity of subsoil in the region of the Vandellòs substation, using the magnetotelluric method.
“This methodology enabled a substantial improvement in the former predictions for GICs. Also, we have proposed a model that can add three factors on which the GIC depend: the magnetic storm, the subsoil geoelectrical structure, and the electricity grid characteristics”, says Marcuello.
Satellite meteorology: anticipating the effects of solar storms
The importance of technological effects of magnetic storms have encouraged around the world the design of warning protocols, able to warn in the minimum time interval -even hours before- to set the proper preventive measures. Situations such as the Quebec blackout in March 13, 1989, with around five million people affected and economic losses of 12 million dollars -are extreme cases that encourage the research process in satellite meteorology to prevent and palliate the magnetic effects of solar activity in the planet.