Geomagnetic Hazards to Conducting Networks
Author: Boteler, D.H.
Source: Natural Hazards, Volume 28, Numbers 2-3, March 2003 , pp. 537-561(25)
Geomagnetic disturbances can disrupt the operation of conducting networks, 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 effects can lead to power blackouts such as occurred on the Hydro-Québec system during a geomagnetic storm in March 1989 leaving 6 million people without power for 9 hours.
Geomagnetic disturbances are the result of eruptions on the Sun that send high energy particles streaming out into space. When these particles reach the Earth 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 band across Canada. It is the magnetic field produced by these ionospheric currents that is seen on the ground as a magnetic disturbance.
Prevention of geomagnetic effects on power systems has focussed on blocking the flow of GIC in the system. However, such measures are expensive and many 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 three latitude regions of Canada.
Research is needed on all aspects of the problem; from new information about solar eruptions for improving forecasting services; to understanding system response to disturbances. Research on geomagnetic disturbances is conducted by the Canadian Geomagnetic Forecasting Centre and a number of active groups at Canadian universities; while research on geomagnetic effects is conducted by affected industries, often in collaboration with the forecasting centre.
Document Type: Research Article
Affiliations: Geomagnetic Laboratory, Geological Survey of Canada 7 Observatory Crescent, Ottawa, Ontario K1A 0Y3, Canada, E-mail: email@example.com
Publication date: March 2003