Geomagnetic Hazards to Conducting Networks

Geomagnetic disturbances can disrupt the operation of conductingnetworks, such as power systems, pipelines and communication cables. In power systems,geomagnetically induced currents (GIC) flow to ground through power transformers,disrupting their operation and causing transformer heating, increased reactive power demand,and generating harmonics that can cause relay misoperation. In extreme cases these effectscan lead to power blackouts such as occurred on the Hydro-Québec system during a geomagneticstorm in March 1989 leaving 6 million people without power for 9 hours. Geomagnetic disturbances are the result of eruptions on theSun that send high energy particles streaming out into space. When these particles reach theEarth they interact with the magnetic field, generating currents that flow down into the ionosphere.The most intense currents are associated with the aurora and occur in an east-west bandacross Canada. It is the magnetic field produced by these ionospheric currents that is seen on theground as a magnetic disturbance. Prevention of geomagnetic effects on power systems hasfocussed on blocking the flow of GIC in the system. However, such measures are expensive andmany utilities rely on forecasts of geomagnetic activity to help them operate during disturbances.The Canadian Geomagnetic Forecast Service, operated by Natural Resources Canada,has been in operation since 1974 and now provides long term and short term forecasts for threelatitude regions of Canada. Research is needed on all aspects of the problem; from newinformation about solar eruptions for improving forecasting services; to understanding systemresponse to disturbances. Research on geomagnetic disturbances is conducted by the CanadianGeomagnetic Forecasting Centre and a number of active groups at Canadian universities; whileresearch on geomagnetic effects is conducted by affected industries, often in collaborationwith the forecasting centre. Copyright Kluwer Academic Publishers 2003