Effects of Geomagnetic Disturbances on the Bulk Power System
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2012 Special Reliability Assessment Interim Report: Effects of Geomagnetic Disturbances on the Bulk Power System February 2012 Embargoed until 12pm EST February 29, 2012 This page intentionally left blank Preface Preface The North American Electric Reliability Corporation (NERC) has prepared the following assessment in accordance with the Energy Policy Act of 2005, in which the United States Congress directed NERC to conduct periodic assessments of the reliability and adequacy of the bulk power system of North America.1,2 NERC operates under similar obligations in many Canadian provinces, as well as a portion of Baja California Norte, México. NERC Mission The North American Electric Reliability Corporation (NERC) is an international regulatory authority established to evaluate reliability of the bulk power system in North America. NERC develops and enforces reliability standards; assesses reliability annually via a 10‐year assessment, and winter and summer seasonal assessments; monitors the bulk power system; and educates, trains, and certifies industry personnel. NERC is the Electric Reliability Organization for North America, subject to oversight by the U.S. Federal Energy Regulatory Commission (FERC) and governmental authorities in Canada.3 Figure A: NERC Regional Entities Table A: NERC Regional Entities FRCC Florida Reliability Coordinating Council MRO Midwest Reliability Organization NPCC Northeast Power Coordinating Council RFC ReliabilityFirst Corporation SERC SERC Reliability Corporation SPP Southwest Power Pool Regional Entity TRE Texas Reliability Entity WECC Western Electricity Coordinating Council Note: The highlighted area between SPP and SERC denotes overlapping Regional area boundaries. NERC assesses and reports on the reliability and adequacy of the North American bulk power system, which is divided into eight regional areas, as shown in the map (Figure A) and corresponding table (Table A). The users, owners, and operators of the bulk power system within these areas account for virtually all the electricity supplied in the United States, Canada, and a portion of Baja California Norte, México. 1 H.R. 6 as approved by of the One Hundred Ninth Congress of the United States, the Energy Policy Act of 2005: http://www.gpo.gov/fdsys/pkg/BILLS‐109hr6enr/pdf/BILLS‐109hr6enr.pdf 2 The NERC Rules of Procedure, Section 800, further detail the Objectives, Scope, Data and Information requirements, and Reliability Assessment Process requiring annual seasonal and long‐term reliability assessments. 3 As of June 18, 2007, the U.S. Federal Energy Regulatory Commission (FERC) granted NERC the legal authority to enforce Reliability Standards with all U.S. users, owners, and operators of the bulk power system, and made compliance with those standards mandatory and enforceable. In Canada, NERC presently has memorandums of understanding in place with provincial authorities in Ontario, New Brunswick, Nova Scotia, Québec, and Saskatchewan, and with the Canadian National Energy Board. NERC standards are mandatory and enforceable in British Columbia, Ontario, New Brunswick, and Nova Scotia. NERC has an agreement with Manitoba Hydro making reliability standards mandatory for that entity, and Manitoba has adopted legislation setting out a framework for standards to become mandatory for users, owners, and operators in the province. In addition, NERC has been designated as the “electric reliability organization” under Alberta’s Transportation Regulation, and certain reliability standards have been approved in that jurisdiction; others are pending. NERC and NPCC have been recognized as standards‐setting bodies by the Régie de l’énergie of Québec, and Québec has the framework in place for reliability standards to become mandatory and enforceable in that jurisdiction. GMDTF Interim Report: Affects of Geomagnetic Disturbances on the Bulk Power System–February 2012 Table of Contents Table of Contents Report Executive Summary .......................................................................................................................... i 1. Space Weather and the Power System ................................................................................... 1 2. Monitoring and Predicting Space Weather ............................................................................ 8 3. Existing Response Capability ................................................................................................. 14 4. Credible Threat Concept and GIC Calculation....................................................................... 16 5. Power Transformers ............................................................................................................. 25 6. Protection and Control ......................................................................................................... 48 7. Other Equipment .................................................................................................................. 58 8. Power System Analysis .......................................................................................................... 62 9. Grid Monitoring Enhancement ............................................................................................. 71 10. GIC Reduction Devices .......................................................................................................... 73 11. Operating Procedures to Mitigate GIC ................................................................................. 79 12. Managing Geomagnetic Disturbance Risks .......................................................................... 82 13. Recommendations ................................................................................................................ 85 Appendices Attachment 1: Acronyms .............................................................................................................. 96 Attachment 2: April 2011 NOAA SWPC Workshop ....................................................................... 98 Attachment 3: NERC Industry Alert ............................................................................................ 102 Attachment 4: Public GMD Response Procedures ..................................................................... 104 Attachment 5: Public OEM Documentation on GMD ................................................................. 105 Attachment 6: Monitoring and Measurement Architecture ...................................................... 106 Attachment 7: View on Risk Management ................................................................................. 109 Attachment 8: Example of GIC Calculations ............................................................................... 118 Attachment 9: NERC GMDTF Roster ........................................................................................... 128 North American Electric Reliability Corporation Staff ................................................................ 137 Effects of Geomagnetic Disturbances on the Bulk Power System–February 2012 Executive Summary I. Executive Summary The highly complex, interconnected North American power grid has provided a long record of reliable, secure delivery of electric power. However, solar storm or geomagnetic disturbance (GMD) events have demonstrated their ability to disrupt the normal operations of the power grid. The most recent example in North America occurred in March 1989, when a GMD led to the collapse of the Hydro‐Québec system, leaving more than six million people without power for nine hours. Figure ES‐1 below shows the March 1989 storm over North America. Understanding the effects of GMD on bulk power systems and the ability of the industry to mitigate their effects are important to managing system reliability. Figure ES‐1: Geomagnetic intensity–March 1989 storm NERC conducted this assessment in response to findings in the High Impact, Low Frequency Event Risk to the North American Bulk Power System (March 2010)4 report, which found the best approach to HILF events was through an organized combination of industry‐led task forces and initiatives. The GMD Task Force implemented that approach for study of geomagnetic disturbances. The breadth of subject matter expertise is shown by the listing of the task force leadership, members, and observers in Attachment 9. I.1 The GMD Phenomena GMD emanate from the sun (see Figure ES‐2). According to scientists, solar coronal holes and coronal mass ejections (CME) are the two main categories of solar activity that drive solar magnetic disturbances on Earth. CME create a large mass of charged solar energetic particles 4 NERC/US Department of Energy, June 2010: High Impact, Low Frequency Event Risk to the Bulk Power System of North America: http://www.nerc.com/files/hilf.pdf i GMDTF Interim Report: Affects of Geomagnetic Disturbances on the Bulk Power System–February 2012 Executive Summary that escape from the sun’s halo (corona), traveling to Earth between 14 and 96 hours.5 These high‐energy particles consist of electrons, along with coronal and solar wind ions.6 Geomagnetic induced currents (GICs) that interact with the power system appear to be produced when a large CME occurs and are directed at Earth. Figure ES‐2: Storm interaction with Earth and transmission lines B t E Charged particles from the CME interact with Earth’s magnetosphere‐ionosphere and produce ionospheric currents, called electrojets. Typically millions of amperes in magnitude, electrojets perturb Earth’s geomagnetic field,