Print this page Geo-magnetic Disturbances
Lee Layton, P.E.
Course Outline
This course begins with a description of solar weather and how geo-magnetic storms are created. Chapter two explains the work being done to predict GMD events. Chapter three explains how GMD’s may impact the electric power industry. Finally, chapter four discusses mitigation options that may help minimize the impact of GMD’s on electric power systems.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
Learning Objective
After taking this course you should,
- Understand how geomagnetic storms may affect the electric utility grid;
- Know the size and scope of the electric utility grid;
- Understand how geomagnetic storms begin;
- Be able to explain the impact of geomagnetic induced currents;
- Know the major historical geomagnetic events;
- Be able to explain electrojets;
- Be able to explain coronal mass ejections;
- Be able to explain a solar proton event;
- Know how to rate the intensity of a geomagnetic storm;
- Know the various satellites in use to monitor geomagnetic storms;
- Be able to explain the risks to the electric utility system; and
- How to mitigate the impact of geomagnetic storms on the electric utility grid.
Intended Audience
This course is intended for electrical engineers and others who want to understand how electric power systems may be affected by geo-magnetic disturbances.
Benefit to Attendees
The potential impacts of geo-magnetic disturbances on the electric power industry is coming under much scrutiny and this course is intended to give the reader a good understanding of the issues affecting the industry and how the issues may be mitigated.
Course Introduction
Geomagnetic storms — a type of space weather that creates disturbances that affect the planet’s magnetic field —have the potential to cause significant damage across the globe with a single event. Severe geomagnetic storms can disrupt the operation of electric power transmission systems and critical infrastructures relying on space-based assets. A geomagnetic storm that degrades the electric power grid would affect not only the energy sector but the transportation, communications, banking, and finance sectors, as well as government services and emergency response capabilities.
Issues with geo-magnetically induced currents (GIC) have been known since the mid-19th century when it was noted that electrical telegraph systems could sometimes run without power during geomagnetic storms, described at the time as operating on the "celestial battery", while at other times they were completely inoperative.
The North American bulk electric power system is perhaps the most critical infrastructure on the continent, for its continued reliable operation supports several other critical infrastructures, including water supply, telecommunications, food and fuel production and distribution, and others. It underpins our government, economy, and society in crucial ways. The U.S. National Academy of Engineering ranked electrification as the greatest engineering achievement of the 20th century, ahead of automobiles, telecommunications, computers, and even healthcare in terms of it positive impact on quality of life.
GMDs start with the sun. Solar coronal holes and coronal mass ejections (CMEs) are the two main categories of solar activity that drive solar magnetic disturbances on the Earth. CMEs involve the ejection of a large mass of charged solar energetic particles that escape from the sun’s halo (corona), in a matter of days, or sometimes just a few hours.
The storms are global phenomena; a single severe storm can adversely impact systems on multiple continents. The disturbance in the Earth’s geo‐magnetic field can cause geo‐magnetically induced currents (GICs) in the ground and electrical network. Once they are introduced into the bulk power system’s transmission and generation facilities, these ground‐induced currents can saturate and may damage some equipment, which can be difficult to immediately replace, such as high voltage transformers, which require long lead times to construct.
These quasi‐DC currents can enter and exit the power system at transformer grounds disrupting the normal operation of the power system and can, in some cases, damage equipment. Because of their proximity to the Earth’s magnetic north pole, higher latitudes typically experience greater effects of GMDs. However, a severe storm can affect equipment and systems even at lower latitudes.
Course Content
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Course Summary
Severe GMDs are relatively rare events. Due to the growth in high voltage transmission systems over the last few decades that are now operating close to their limits, GMDs could pose a credible reliability risk. The greatest risk scenario involves widespread damage to high‐voltage transformers and long recovery times. Reactive power loadings on hundreds of transformers could sky rocket, causing heating issues and potential large-scale voltage collapses, power system software like state estimation could fail, control room personnel would be overwhelmed, and the storm could last for days with varying intensity.
Procedures are in place to observe solar activity, measure the severity of Earth‐directed solar activity at the L1 Lagrange point, and relay this information rapidly to interested parties. Capabilities are also in place to provide forecasts of potential GMDs in the form of warnings, alerts, and watches.
Technologies exist that can be retrofitted to transmission equipment to reduce vulnerability to GMDs such as neutral grounding resistors to reduce GIC flow in high‐voltage transmission lines.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
