Geomagnetically induced current. Geomagnetically induced currents (GIC), affecting the normal operation of long electrical conductor systems, are a manifestation at ground level of space weather. During space weather events, electric currents in the magnetosphere and ionosphere experience large variations, which manifest also in the Earth's magnetic field. These variations induce currents (GIC) in conductors operated on the surface of Earth. Electric transmission grids and buried pipelines are common examples of such conductor systems. GIC can cause problems, such as increased corrosion of pipeline steel and damaged high-voltage power transformers. GIC are one possible consequence of geomagnetic storms, which may also affect geophysical exploration surveys and oil and gas drilling operations. Background[edit] The Earth's magnetic field varies over a wide range of timescales. Risk to infrastructure[edit] GIC in power grids[edit] Grid management is also aided by space weather forecasts of major geomagnetic storms.
Www.agu.org/pubs/current/si/links/2007JA012487.pdf. Solar Storm induced HVAC Megawatt Transformer failure is completly avoidable ... Global Geomagnetic Storm Induced Failure of 400 Mega-HVAC Transformers is Avoidable by Redundant HVAC Transformer Arrays - or - A Current and Voltage Division Method to Reduce Mega-HVAC Transformer Failures by Redundant Transformer Arrays Abstract During severe solar storms HVAC transformers used by utilities of dimensional size similar to a medium sized house are subject to catastrophic failure. As these transformers have very long commissioning and repair schedules their failure poses a catastrophic risk.
Large parts of grids that depend on their existence of these AC transformers can be rendered non-functioning when the mega transformers fail. This catastrophe can be avoided by using simple voltage division and current division principals implemented in the form of redundant arrays of smaller HVAC transformers. Electric power is modern society's cornerstone technology on which virtually all other infrastructures and services depend. The problem Definitions Physics. Real-time forecast service for geomagnetically induced currents. Geomagnetically Induced Currents When a coronal mass ejection (CME), a huge plasma cloud originating from the Sun, hits the Earth, it causes a space weather storm. Electrons in the Earth's magnetosphere cascade into the polar regions, creating a current that flows along the auroral oval. When these currents change in time an electric field will be induced in the ground. The electric field will act as a celestial battery driving currents in the ground and in man-made conductors such as communication cables, pipelines electric power transmission grids and railway equipment.
Normally part of a power system consist of Y-configurated transformers connected to 3-phase transmission lines in a network. GICs have frequencies < 1 Hz, which are very small compared to the 50 or 60 Hz AC in the power system. The history of GICs dates back about 150 years. Www.esa-spaceweather.net/spweather/workshops/spw_w4/proceedings/PulkkinenPoster.pdf. Space Weather: How Currents in Space Produce Currents in Power Grids.