Open AccessEffects of neutral point reactors and series capacitors on geomagnetically induced currents in a high‐voltage electric power transmission system
Author(s) -
Arajärvi Esko,
Pirjola Risto,
Viljanen Ari
Publication year - 2011
Publication title -
space weather
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.254
H-Index - 56
ISSN - 1542-7390
DOI - 10.1029/2011sw000715
Subject(s) - capacitor , geomagnetically induced current , electric power transmission , equivalent series resistance , electrical engineering , transformer , voltage , power transmission , engineering , power (physics) , physics , magnetic field , earth's magnetic field , thermodynamics , quantum mechanics , geomagnetic storm
Geomagnetically induced currents (GIC) are DC‐like currents compared to power transmission frequencies. Consequently, it may be possible to reduce the magnitudes of GIC by installing resistive components or series capacitors into a power grid. We simulate the effects of neutral point reactors and series capacitors on GIC in the Finnish 400 kV network. Reactors add an additional resistance to earthing leads of transformers, and series capacitors block the flow of GIC in transmission lines. The geoelectric field impacting the system is considered to be uniform. The use of reactors does not necessarily reduce the GIC risk. Although the installation of reactors tends to decrease GIC on the average, maximum GIC may even increase. Assuming a reactor at all stations results in a 50% reduction of the maximum GIC compared to the situation with no reactors. With up to four series capacitors, the maximum GIC is reduced by 40% when they are optimally located. However, even small changes in the topology of the grid can cause large changes in GIC. A combination of reactors and series capacitors could in principle provide a way to diminish the GIC risk. This study also emphasizes the difficulty of preventing GIC problems by these means.