IEEE PES Boston Chapter & IEEE Com Soc Boston Chapter Joint Lecture

Space Weather in Solar Cycle 24: Is the Power Grid at Risk?

Wayne H. Hagman

April 16, 2013

11

Acknowledgements

I would like to acknowledge the efforts of Susan Soergel aiding me in the production of this lecture. Susan “kindly” suggested I might participate in a lecture on this subject. She then helped with research of early solar magnetic disturbance effects on man-made electromagnetic systems. Space and time limitations prevented me from using all the material she so kindly provided. Finally, she “photo-shopped” some photographs for me to develop images of transformer core magnetization effects. I greatly appreciate Susan’s assistance.

Title page photo is from: Louis J. Lanzerotti, “Space Weather and Its Effects,” Scientific Committee on Antarctic Research Lecture to XXXI Antarctic Treaty Consultative Meeting, Kiev, Ukraine, June 2008, http://www.scar.org/communications/atcmpresentation/ATCM31_Kiev -Lecture_comp.pdf.

http://www.scar.org/communications/atcmpresentation/ATCM31_Kiev-Lecture_comp.pdfhttp://www.scar.org/communications/atcmpresentation/ATCM31_Kiev-Lecture_comp.pdf

22

Presentation OverviewEarly man-made electromagnetic systemsCorrelation of sunspot activity & major electrical system disturbancesMechanism of geomagnetic current inductionFirst order effects on power systemsTransformer magnetizationSecond order effects on power systemsShunt reactors & shunt capacitors - reactanceCurrent transformersProtective relaysAugust 4, 1972March 13, 1989Mitigation strategiesConclusionsReferences

33

Early Man-Made Electromagnetic Systems

Some of the earliest man-made electromagnetic systems were developed to provide “higher bandwidth”communications:

Telegraphy using wires

Telephony using wires

Radio telegraphy using radio waves

Railroads & railroad signaling systems

In all four systems, once long distances became involved, practitioners started observing “information transfer rate” phenomena (usually degradation) that were eventually correlated with solar activity.

44

TelegraphyParticularly severe disruptions to the telegraph system occurred in 1848,1859-60, 1872, 1883. The largest one was on Oct 30 – 31, 1903. [K1]

May 28, 1877 - telegraph lines affected from Boston, Baltimore, Philadelphia, & Washington, DC. [K2]

August 12, 1880 - telegraph lines could send messages between Hartford & Boston without battery for nearly 2 hours. [K3]

Nov 17, 1882 - all telegraph [activity] east of the Mississippi and north of Washington, DC, ceased. Wires with earth circuits wereunusable though systems using the newer 'metallic' circuits were un affected. Buried cables and above ground cables were equally affected. People who attempted to use telephones heard buzzing or ringing noises. [K4]

The problems occurred on systems that used the earth (ground) aspart of the circuit.

55

Telephony

Disruptions to telephone systems occurred with far lower frequency, however.

One reason for the reliability is that telephone systems are inherently two-wire systems not relying on the earth for a return path.

However, the major reason for the higher reliability turns out to be due to safety considerations. Telephone engineers understood early on that users of their technology would be in close contact with instruments that were directly connected to wires that traveled from point A to point B on the earth. Such wires were susceptible tostatic charge & lightning overvoltage effects, which could not be tolerated both from the standpoint of customer safety and risk of structure fires. Therefore, the carbon block spark gap surge suppressor was developed for telephone applications [C13].

The surge suppressor isolated both wires from ground, providing a spark gap discharge voltage rating of between 500 & 1,000 volts,which turns out to be higher than the voltages induced in all but the worst solar magnetic storms.

66

Radio Telegraphy

While radio telegraphy does not rely on wires, variations in reception were observed, and eventually correlation was made with solar phenomena.

An early correlation of radio reception with solar phenomena was made in a 1917 paper presented to the IRE wherein the author, who was involved in setting up a radio network in the Dutch East Indies, noted a correlation between reception changes and the aurora borealis, but had no idea why [C1].

Actual understanding of the relation between sunspot activity and radio reception had to wait for two things:

Development of sufficient technology to accurately measure transmitted and received power.

Use of radio technology for long enough that one or more 11-year sunspot cycles were experienced.

Correlation between abnormal radio transmission and disturbances in the earth’s magnetic field was reported in a 1925 by Bell Labs scientists working on transatlantic radiotelephone communication [C2].

Further empirical observation & research was reported from 1925-1932, some based on observations recorded between 1900 & 1910 (there’s that need to see an entire 11 year cycle) [C3, C4, C5, C6, C7, C8, C9, C10, C11, C12].

77

Railroad SignalingRailroad signaling systems were developed to prevent collisions and allow better utilization of physical plant, i.e., more trains down a given track in a certain amount of time.

May 13, 1921 - The New York Railroad Storm - The prelude to this particularstorm began with a major sunspot sighted on the limb of the sun vast enough to be seen with the naked eye through smoked glass. The spot was 94,000 miles long and 21,000 miles wide and by May 14th was near the center of the sun in prime location to unleash an earth-directed flare. The 3-degree magnetic bearing change among the five worst events recorded ended all communications traffic from the Atlantic Coast to the Mississippi. At 7:04 AM on May 15, the entire signal and switching system of the New York Central Railroad below 125th street (in New York City – on the approach to Grand Central Station) was put out of operation, followed by a fire in the control tower at 57th Street and Park Avenue. No one had ever heard of such a thing having happened during the course of an auroral display. The cause of the outage was later ascribed to a 'ground current' that had invaded the electrical system. Railroad officials formally assigned blame for a fire that destroyed the Central New England Railroad station, to the aurora. Telegraph Operator Hatch said that he was actually driven away from his telegraph instrument by a flame that enveloped his switchboard and ignited the entire building at a loss of $6,000. Over seas, in Sweden, a telephone station was 'burned out', and the storm interfered with telephone, telegraph and cable traffic over most of Europe. Aurora were visible in the Eastern United States, with additional reports from Pasadena, California where the aurora reached zenith.

This solar storm is estimated to be about 10 times the magnitude of the 1989 storm that took down the Hydro-Quebec power grid.

[K5]

88

A Correlation of Sunspot Activity & Major Electrical System Disturbances

[B1]

Telegraph Systems

Telegraph Systems Power & Telephone Systems

99

Induction Of Geomagnetic Currents

[D10]

Low frequency variations in the earth’s magnetic field link the loop formed by long earth-based conductors (transmission lines, telephone lines, pipelines, etc.) and the earth, inducing a circulating current that flows around the conductor-earth loop. This is a manifestation of Faraday's Law of Induction on a grand scale.

1010

Earth Conductivity In US & Canada

[D4]

The susceptibility of man- made electromagnetic

systems to geomagnetically- induced currents is higher in

regions with lower conductivity & where wires

are oriented east-west.

1111

Probability Of Geomagnetic Storms In US & Canada

[D4]

The probability of a geomagnetic storm in which the field change is greater

than 300 nanotesla per minute can be as high as

0.2 % per unit time. But the impact of the storm on a power system depends on

the earth’s local resistivity.

1212

Path Of Geomagnetically-Induced Currents In Electric Power Systems

[D4]

1313

First Order Effect On Power Systems Of Geomagnetically-Induced Current

Any power transformer with a grounded Y connection is susceptible to having low frequency (near DC) current flow through its windings.

The most susceptible transformers are those on extra high voltage (EHV) transmission systems, because those systems are very solidly grounded.

The design of the magnetic core also affects the susceptibility of the transformer to magnetic saturation due to low frequency currents.

DC current flowing in a transformer winding alters the magnetic and electrical properties of the transformer – it no longer “behaves” like a transformer, rather it morphs into a multi-headed beast that causes many problems on the power system.

[E13]

1414

Normal Power Transformer Magnetic State

Under normal conditions, the excitation of the transformer core is balanced between the positive and negative peaks of the sine wave.

Economical transformer design dictates that the magnetic capabilities of the core be almost fully used during normal operation, i.e., the core operates just below the magnetic saturation point.

When a core is below the saturation point, virtually all of the magnetic flux is contained in the core.

The magnetic reluctance of the core is low. The magnetization losses are low and the (shunt) magnetizing inductance is high, resulting in a very small magnetizing current. The inductive volt-amperes-reactive (VAR) requirements of the transformer are very low.

Essentially, all the current that goes in the primary comes out the secondary. An unloaded transformer looks like an open circuit.

With non-saturated core magnetization, the transformer voltage and current waveforms contain very low harmonic content – the waveforms are essentially sinusoidal at 60 Hz (in North America).

1515

Power Transformer Equivalent Circuit – Normal Core Magnetization

[K6 p. 98]

Magnetizing (Core) Inductance

Magnetization (Core) Loss

Two Winding Transformer Equivalent Circuit Showing Core Magnetization Elements

Between Line &Ground

Under normal excitation conditions the magnetization (resistive) loss is small &

the magnetizing inductance is large, Ih & Im are small.

1616

Single Phase Transformer With Three-Legged Core

1717

Transformer With Normal Magnetic Field (Core Not Saturated)

The magnetic flux is entirely contained within the core.

No flux intersects (links) the tank wall.

1818

Effect Of Geomagnetic (Low Frequency) Currents On Power Transformers

When geomagnetic (low-frequency) currents flow in a transformer winding, the excitation of the transformer is biased in one direction or the other, resulting in half-cycle saturation of the core.

When the core saturates, it has reached the limit of its ability to carry a magnetic field, and any field beyond the limit comes out of the core and passes through the air as “leakage flux”.

The magnetic reluctance of the core is still low. However, the magnetic reluctance of the portion of the magnetic circuit outside the core is high. This results in a much-lowered value of shunt inductance, and a large shunt current flows through the magnetizing branch. The inductive volt-amperes-reactive (VAR) requirements of the transformer are very high.

Now, there is current going into the primary that is not coming out the secondary. A saturated transformer looks like a shunt reactor. Problems can occur with differential protective relays that are looking to see balanced primary & secondary currents, i.e., the transformers may trip.

With saturated core magnetization, the transformer voltage and current waveforms contain very high harmonic content – the waveforms are no longer sinusoidal.

1919

Power Transformer Equivalent Circuit – Saturated Core Magnetization

[K6 p. 98]

Magnetizing (Core) Inductance

Magnetization (Core) Loss

Two Winding Transformer Equivalent Circuit Showing Core Magnetization Elements

Between Line &Ground

With the core saturated the magnetization loss grows and

the magnetizing inductance becomes small, Ih grows & Im is very large.

2020

Transformer With Leakage Flux (Core Saturated)

The magnetic flux is escaping the core & passing through the “Air”.

Flux now intersects (links) the tank wall –

inducing current &

causing unwanted heating.

2121

Second Order Effects On Power Systems Of Geomagnetically-Induced Current

Leakage flux in transformers that links any conductive material will cause induced currents (eddy & circulating) which will result inalmost immediate severe localized, unwanted, unexpected, heatingdue to resistive losses, e.g., paint burning off transformer tank walls.

The localized heating effect is not unlike the heating in a microwave oven (particularly if you put foil in the oven!) – the difference is in the frequency of the electromagnetic radiation causing the heating.

If the unwanted heating is in portions of the transformer that were not designed to get [that] hot, transformer failures may occur.

Non-sinusoidal voltage waveforms (high harmonic content) will also affect shunt capacitor banks, current transformers, & protectiverelays.

2222

Transformer Winding Failure Due To Localized Abnormal Heating

[D4, D8]

~ 4”

Transformer Tank Wall

(No Damage)

Normal Winding Disk With

Undamaged Insulating Paper

Failed Winding Disk With

Insulating Paper Burned Off & Melted Copper

Strands

2323

Shunt Reactors & Shunt Capacitors

Shunt capacitor banks are used to offset inductive effects on the power system – to support voltage.

Shunt reactors are used to offset the effects of capacitance on the system –to lower voltage.

Typically, shunt capacitors are switched in during periods of high load, and shunt reactors are switched in during periods of light load.

The same effects can be achieved – within rating limits - by varying the excitation on generators, i.e., operation as “synchronous condensers”.

Static VAR compensators (SVC’s), which combine capacitor banks and reactors, also provide similar compensation & voltage support, with very fast automated controls.

Many power systems once had dedicated synchronous condensers (rotating machines). However, capacitor banks are cheaper & capacitor technology advanced to the point where reliability became excellent, so synchronous condensers were retired.

2424

Inductive & Capacitive Reactance

Inductive Reactance

LfXL π2=

Capacitive Reactance

CfXC

π21

=

As inductance, L, goes down, inductive reactance (impedance) drops.

Saturated transformers have low shunt magnetizing inductance, so they draw high currents. They look like shunt reactors on the system, dragging down the system voltage.

As frequency, f, goes up, capacitive reactance (impedance) drops.

Capacitor banks have lower impedances to harmonics. They draw larger currents when harmonics are present.

2525

Abnormal Reactance Effects On Power Systems During Geomagnetic Events

Unwanted shunt inductance of saturated transformers draws large currents, forcing system voltage down.

Capacitor banks also draw large currents, partially offsetting the inductive effects.

Essentially, the saturated transformers are in a tug-of-war with the capacitors on the system.

Modern shunt capacitors have very low loss, and are, therefore, less susceptible to transient heating damage due to excess current. However, large currents may affect other components in capacitor bank installations, resulting in damage & unwanted tripping. Voltage imbalance and overvoltage protection may also be “fooled” by harmonic voltage spikes and cause unwanted trips. Finally, overcurrent protection may also operate spuriously in the face of harmonic currents. [H2] Similar issues may apply to SVC’s.

Without capacitive voltage support, the system voltage may collapse, causing a blackout.

Rotating machines have fairly high thermal inertias, so generators operated as synchronous condensers have a higher probability of staying on line.

2626

Effects On Current Transformers (CT’s) During Geomagnetic Events

CT’s are used to “measure” currents flowing in power system components and supply proportionally lower currents to measurement and protective devices, i.e., protective relays.

It is important to have accurate measurements of system state during abnormal operating conditions!

CT’s also have a magnetic core, although they typically operate at lower magnetization levels than power transformers – because reading accuracy must be maintained in the face of large fault currents. So CT’s have some “built in margin”.

Research has shown that higher ratio CT’s (≥ 400:1) are less susceptible to magnetic saturation during geomagnetic events [H1].

CT’s with lower burden (load) are also less susceptible to magneticsaturation {H1].

[H1, H2, H3]

2727

Protective Relays

Protective relays are used to disconnect (trip) elements of the power system, and/or notify operators, when abnormal system operation occurs, e.g., faults. These relays typically use signals from current transformers (CT’s) and potential transformers (PT’s) as inputs.

There are two general forms of protective relays in use on powersystems:

Electromechanical relays (the original form of relay)Electromechanical relays sense abnormal conditions through imaginative and novel use of electromagnetic principles and devices in reaction to current and voltage inputs. They are typically very robust, but perform only one of two functions.

Microprocessor relays (the modern electronic relay)Microprocessor relays sense abnormal conditions through the use of algorithmic analysis of current and voltage inputs. One relay may perform many different functions, based on multiple algorithms running in its microprocessor.

[H1, H2, H3]

2828

Effects On Protective Relays During Geomagnetic Events

Both forms of protective relays may behave in unexpected ways during geomagnetic events.

Firstly, the relay can only operate based on its inputs – if a CT is supplying a distorted waveform due to the effects of harmonic saturation, the relay may respond in a different, and perhaps unwanted, way than it does to nearly sinusoidal inputs.

Secondly, the internal functionality of the relay itself may lead to an unexpected response, either tripping when such action is unwarranted, or not operating when it should. Transformer differential relays are a good example of this phenomena. Harmonic restraints – typically used to prevent tripping on inrush currents, do a good job of preventing false trips due to core saturation effects. However, operation of the relay may be so restrained that it will not operate in the face of a true transformer internal failure.

Different manufacturers achieve similar relay performance using different internal approaches. The behavior of various relays must be evaluated with respect to the conditions that can be expected to occur during geomagnetic events. This evaluation has proceeded at varying paces depending on where in the sunspot cycle we are and the motivation of individual relay manufacturers. [H1, H2, H3]

2929

Event Of August 4, 1972 {1}

A K-8 geomagnetic storm occurred August 4-5, 1972.

The Edison Electric Institute (EEI) had been sponsoring a research project since 1968 looking at Solar Magnetic Disturbances wherein the participants installed recording DC ammeters in the neutral leads of selected grounded-Y transformers.

Ironically, the EEI had participated in a similar information gathering effort following the first recorded solar magnetic disturbance effect on an electric power system, March 24, 1940 [F1].

Categories of disturbances reported included:

Shifts in MVAR flow of up to 300%Shifts in MW flow of up to 33%Voltage fluctuations up to 30%Frequency shift of up to 2%Relay operations (some relays did not have harmonic restraints)3rd harmonic currents in transformer tertiary windingsCommunication, telemetering, & supervisory alarm failures

[F2]

3030

Event Of August 4, 1972 {2}

Disturbances occurred across northern North America and in the eastern half of the US.

Virtually all disturbances occurred simultaneously, at 1742 EST.

There was no widespread voltage collapse… [F2]

3131

Event Of March 13, 1989 {1}

A K-9 geomagnetic storm occurred March 13, 1989.

On the Hydro-Quebec system the effects were devastating:

Seven SVC’s tripped within 59 seconds of each other as a result of excessive harmonicsFive 735kV transmission lines associated with the SVC’s tripped9 GW of generation was lost due to system instabilityAutomatic load-shedding equipment operated but was unable to cope with such a large perturbationThe loss of SVC’s, transmission lines, and generation ultimately resulted in the voltage collapse of the Hydro-Quebec system approximately 25 seconds later.The outage lasted 9 hours (time to restore 83% of customers).Various equipment was damaged by transient overvoltages that occurred as the system voltage oscillated wildly during the voltage collapse.

[B1, H2]

3232

Event Of March 13, 1989 {2}

The Northeast Power Coordinating Council (NPCC) and Mid-Atlantic Area Council (MAAC) power pools, which serve the entire northeastern US from New England to Washington, DC, were nearly involved in a cascading system collapse.

Public Service Electric & Gas (NJ) suffered damage to a generator step-up transformer, which had to be replaced.

Allegheny Power System (PA, WV, VA) experienced tank wall heating on an autotransformer at Meadowbrook substation.

Five 130 kV lines tripped in Sweden.

[B1, B4, H2, D8]

3333

Mitigation Strategies {1}The first requirement for mitigation of solar magnetic disturbance effects is to realize that such a storm is about to happen, or is happening:

Prediction of solar storm effects on power systems (as well as communications systems, etc.) [G1, G2]Monitoring of low frequency currents and their effects[J1, J2, J3]:

DC neutral current monitors on susceptible Y-connected transformersHarmonic current and/or voltage monitoring on susceptible transformers and other power system componentsRequires accurate modeling of solar magnetic disturbance effects[E2, E3, E5, E7, E8, E9, E10, E12, E13, E14]]

Neutral blocking devices can be applied to power transformers E6, E11]. These are not without their own issues…

3434

Mitigation Strategies {2}Available reaction times are very small, so pre-planning is necessary [F7, F17, G3, G4, G5].

Transformer & system loading can be reduced ahead of time:

Equipment starts an event in a more advantageous thermal state. However, localized heating due to leakage flux is almostinstantaneous, so reducing transformer temperatures ahead of time may not help, as the normal large thermal inertia only helps with distributed heatingReduced system load can provide greater operating margin. However, the proper load point requires study, as too little load removes damping effects from the system.

Generating entities should be required to operate as synchronous condensers (with appropriate compensation).

3535

Kirk: “Bridge to Engineering…” (loud static & red alert sounds in background)Scott: “Scott here, Capt’n. I can barely hear you. Our communication channel is failing.”Kirk: “Scotty, the Romulan Inductive VAR Device is perturbing the magnetic field.

I need more Capacitive VARS!”Scott: “Aye, Capt’n, I’m giving you all she’s got. I can’t change the laws of physics!

The cap banks are tripping out, and… the synchronous condensers are inthe Starfleet Academy Museum… We took those dinosaurs out years ago…to reduce maintenance costs and make room for more cap banks.”

Something To Think About…

http://trekmovie.com/2009/04/21/review-star-trek-the-original-series-season-1-blu-ray/, http://marketpreview.blogspot.com/2008_05_01_archive.html

http://trekmovie.com/2009/04/21/review-star-trek-the-original-series-season-1-blu-ray/http://marketpreview.blogspot.com/2008_05_01_archive.html

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References

A - Solar Physics[A1] J. Watermann, “Space Weather Effects Observed on the Ground,” Online Proceedings of the First European Space Weather Week, European Space Agency, ESA-ESTEC, Noordwijk, The Netherlands, November 29-December 3, 2004, http://www.esa-spaceweather.net/spweather/workshops/esww/proc/watermann.pdf.[A2] “The Sunspot Cycle,” Marshall Space Flight Center, National Aeronautics and Space Administration, http://solarscience.msfc.nasa.gov/SunspotCycle.shtml, Updated 2013/01/02.[A3] “Solar Cycle Prediction,” Marshall Space Flight Center, National Aeronautics and Space Administration, http://solarscience.msfc.nasa.gov/predict.shtml, Updated 2013/01/02.

B – Chronology of Events[B1] D. H. Boteler, R. J. Pirjola, and H. Nevanlinna, “The Effects of Geomagnetic Disturbances on Electrical Systems at the Earth’s Surface,” Advances in Space Research, Vol. 22, Issue 1, 1998, pp. 17-27.[B2] Louis J. Lanzerotti, “Space Weather and Its Effects,” Scientific Committee on Antarctic Research Lecture to XXXI Antarctic Treaty Consultative Meeting, Kiev, Ukraine, June 2008, http://www.scar.org/communications/atcmpresentation/ATCM31_Kiev-Lecture_comp.pdf.[B3] Louis J. Lanzerotti, “Space Weather and Its Effects,” Lecture Notes, Scientific Committee on Antarctic Research Lecture to XXXI Antarctic Treaty Consultative Meeting, Kiev, Ukraine, June 2008, http://www.scar.org/treaty/atcmxxxi/ATCM31_IP60_Lecture.pdf.[B4] “Chronology of Effects,” Space Weather Canada, Government of Canada, July 23, 2012, http://spaceweather.ca/tech/se-chr-eng.php.

http://www.esa-spaceweather.net/spweather/workshops/esww/proc/watermann.pdfhttp://www.esa-spaceweather.net/spweather/workshops/esww/proc/watermann.pdfhttp://solarscience.msfc.nasa.gov/SunspotCycle.shtmlhttp://solarscience.msfc.nasa.gov/predict.shtmlhttp://www.scar.org/communications/atcmpresentation/ATCM31_Kiev-Lecture_comp.pdfhttp://www.scar.org/treaty/atcmxxxi/ATCM31_IP60_Lecture.pdfhttp://spaceweather.ca/tech/se-chr-eng.php

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C - Radio & Wired Communication Systems[C1] Cornelis J. De Groot, “On the Nature and Elimination of Strays,” Proceedings of the Institute of Radio Engineers, Vol. 5, No. 2, April 1917, pp. 75-132.[C2] Lloyd Espenschied, C. N. Anderson, and Austin Bailey, “Transatlantic Radiotelephone Transmission,”Bell System Technical Journal, Vol. 4, Issue 3, July 1925, pp. 459-507; also published in Proceedings of the Institute of Radio Engineers, Vol. 14, No. 1, February 1926, pp. 7-56.[C3] Greenleaf W. Pickard, “The Effect of the Solar Eclipse of January 25, 1925, on Radio Reception,”Proceedings of the Institute of Radio Engineers, Vol. 13, No. 5, October 1925, pp. 539-569.[C4] Greenleaf W. Pickard, “The Correlation of Radio Reception With Solar Activity and Terrestrial Magnetism,” Proceedings of the Institute of Radio Engineers, Vol. 15, No. 2, February 1927, pp. 83-97.[C5] Greenleaf W. Pickard, “The Correlation of Radio Reception With Solar Activity and Terrestrial Magnetism. II.,” Proceedings of the Institute of Radio Engineers, Vol. 15, No. 9, September 1927, pp. 749-766.[C6] L. W. Austin, “Long-Wave Radio Measurements at the Bureau of Standards in 1926, With Some Comparisons of Solar Activity and Radio Phenomena,” Proceedings of the Institute of Radio Engineers, Vol. 15, No. 10, October 1927, pp. 825-836.[C7] L. W. Austin, “Radio Atmospheric Disturbances and Solar Activity,” Proceedings of the Institute of Radio Engineers, Vol. 15, No. 10, October 1927, pp. 837-842.[C8] Clifford N. Anderson, “Notes on the Effect of Solar Disturbances on Transatlantic RadioTransmission,” Proceedings of the Institute of Radio Engineers, Vol. 17, No. 9, September 1929, pp. 1528-1535.[C9] K. Sreenivasan, “On the Relation Between Long-Wave Reception and Certain Terrestrial and Solar Phenomena,” Proceedings of the Institute of Radio Engineers, Vol. 17, No. 10, October 1929, pp. 1793-1814.[C10] Eitaro Yokoyama and Tomozo Nakai, “Effects of Sun Spots and Terrestrial Magnetism on Long-Distance Reception of Low-Frequency Waves,” Proceedings of the Institute of Radio Engineers, Vol. 19, No. 5, May 1931, pp. 882-890.

References

3838

[C11] Clifford N. Anderson, “Notes on Radio Transmission,” Proceedings of the Institute of Radio Engineers, Vol. 19, No. 7, July 1931, pp. 1150-1165.[C12] L. W. Austin, “Solar Activity and Radio Telegraphy,” Proceedings of the Institute of Radio Engineers, Vol. 20, No. 2, February 1932, pp. 280-285.[C13] “Overvoltage Protection of Solid-State Subscriber Loop Circuits,” Application Note 080942, ZarlinkSemiconductor, Inc., September 17, 2002.[C14] “Geomagnetic Effects on Radio Propagation,” Space Weather Canada, Government of Canada, November 22, 2011, http://spaceweather.ca/tech/se-hf-eng.php.[C15] “Geomagnetic Effects on Communication Cables,” Space Weather Canada, Government of Canada, November 29, 2011, http://spaceweather.ca/tech/se-cab-eng.php.

D - General Power Systems Solar Magnetic Disturbance Effects[D1] “Forum: Geomagnetic Disturbances and Electric Power Systems,” IEEE Power Engineering Review, July 1989, pp. 6-9.

“Magnetic Storm Blamed for Hydro-Quebec Failure,” Reprinted from CEA “Bulletin” April 1989Robert J. Ringlee and James R. Stewart, “Geomagnetic Effects on Power Systems.”

[D2] John Douglas, “A Storm From the Sun,” IEEE Power Engineering Review, December 1989, pp. 11-13.[D3] John Kappenman and Vernon D. Albertson, “Bracing for the Geomagnetic Storms,” IEEE Spectrum, March 1990, pp. 27-33.[D4] Tom S. Molinski, William E. Feero, and Ben L. Damsky, “Shielding Grids From Solar Storms,” IEEE Spectrum, November 2000, pp. 55-60.[D5] Samuel K. Moore, “Extreme Solar Storm Strikes Earth,” IEEE Spectrum, December 2003, pp. 15-16.[D6] Leontina M.V.G. Pinto, Jacques Szczupak, Márcio A. Drummond, Luiz H. Macedo, Luiz Muniz Barreto, “Geomagnetically Induced Currents: The Ultimate Threat to System Security,” Paper presented at 2005 IEEE Russia Power Tech, St. Petersburg, Russia, June 27-30, 2005.

References

http://spaceweather.ca/tech/se-hf-eng.phphttp://spaceweather.ca/tech/se-cab-eng.php

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[D7] Risto J. Pirjola and David H. Boteler, “Geomagnetically Induced Currents in European High-Voltage Power Systems,” Proceedings of the 2006 Canadian Conference on Electrical and Computer Engineering, Ottawa, ON, May 7-10, 2006, pp. 1263-1266.[D8] James A. Marusek, “Solar Storm Threat Analysis,” Impact, 2007, http://www.breadandbutterscience.com/SSTA.pdf.[D9] Peter Behr and ClimateWire, “Solar Flare This Week Illuminated Power Grid’s Vulnerability,”Scientific American, June 9, 2011, http://www.scientificamerican.com/article.cfm?id=solar-flare-this-week-illluminated-power-grid-vulnerability.[D10] “Geomagnetic Effects on Power Systems,” Space Weather Canada, Government of Canada, November 22, 2011, http://spaceweather.ca/tech/se-pow-eng.php.[D11] John Kappenman, “A Perfect Storm of Planetary Proportions,” IEEE Spectrum, February 2012, pp. 26-31.

E - Power Transformers[E1] B. A. Cogbill, “Are Stabilizing Windings Necessary in All Y-Connected Transformers?,”Transactions of the American Institute of Electrical Engineers, Part III: Power Apparatus and Systems, Vol. 78, No. 3, October 1959, pp. 963-970.[E2] W. J. McNutt, “Operation of Power Transformers During Major Power System Disturbances,”Publication No. GET-3237, Power Transformer Department, General Electric Company, Pittsfield MA, June 1966.[E3] G. W. Alexander, S. L. Corbin, and W. J. McNutt, “Influence of Design and Operating Practices on Excitation of Generator Step-Up Transformers,” IEEE Transactions on Power Apparatus and Systems, Vol. PAS-85, No. 8, August 1966, pp. 901-909.[E4] “The Whys of the Wyes,” Publication No. GET-3388B, Power Transformer Department, General Electric Company, Pittsfield MA, December 1967.[E5] W. McNutt, “The Effect of GIC on Power Transformers,” Presentation at the Special Panel Session “Geomagnetic Storm Cycle 22: Power System Problems on the Horizon,” July 17, 1990, IEEE PES Summer Meeting, Minneapolis, MN, July 15-19, 1990.

References

http://www.breadandbutterscience.com/SSTA.pdfhttp://www.scientificamerican.com/article.cfm?id=solar-flare-this-week-illluminated-power-grid-vulnerabilityhttp://www.scientificamerican.com/article.cfm?id=solar-flare-this-week-illluminated-power-grid-vulnerabilityhttp://spaceweather.ca/tech/se-pow-eng.php

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[E6] J. G. Kappenman, S. R. Norr, G. A. Sweezy, D. L. Carlson, V. D. Albertson, J. E. Harder, B. L. Damsky, “GIC Mitigation: A Neutral Blocking / Bypass Device to Prevent the Flow of GIC in Power Systems,” IEEE Transactions on Power Delivery, Vol. 6, No. 3, July 1991, pp. 1271-1281.[E7] Shu Lu, Yilu Liu, and Jaime De La Ree “Harmonics Generated From a DC Biased Transformer,”IEEE Transactions on Power Delivery, Vol. 8, No. 2, April 1993, pp. 725-731.[E8] Y. You, E. F. Fuchs, and P. R. Barnes, “Reactive Power Demand of Transformers with DC Bias,”Conference Record of the 1994 IEEE Industry Applications Society Annual Meeting, Boulder, CO, October 2-6, 1994, pp. 339-346.[E9] Matti Lahtinen and Jarmo Elovaara, “GIC Occurrences and GIC Test for 400 kV System Transformer,” IEEE Transactions on Power Delivery, Vol. 17, No. 2, April 2002, pp. 555-561.[E10] Philip R. Price, “Geomagnetically Induced Current Effects on Transformers,” IEEE Transactions on Power Delivery, Vol. 17, No. 4, October 2002, pp. 1002-1008.[E11] Léonard Bolduc, Michel Granger, Grégoire Paré, Jean Saintonge, and Luc Brophy, “Development of a DC Current-Blocking Device for Transformer Neutrals,” IEEE Transactions on Power Delivery, Vol. 20, No. 1, January 2005, pp. 163-168.[E12] Peter M. Balma, Ramsis Girgis, Hasse Nordman, Léonard Bolduc, “Geomagnetic Induced Currents and the Effects on Power Transformers,” Tutorial Session, March 8, 2010, IEEE PES Transformers Committee Spring 2010 Meeting, Houston, TX, March 7-11, 2010.[E13] R. Girgis and K. Vedante, “Effects of GIC on Power Transformers and Power Systems,” Paper presented at the 2012 IEEE PES Transmission and Distribution Conference and Exposition, Orlando, FL, May 7-10, 2012.[E14] Luis Marti, Afshin Rezaei-Zare, and Arun Narang, “Simulation of Transformer Hotspot Heating Due to Geomagnetically Induced Currents,” IEEE Transactions on Power Delivery, Vol. 28, No. 1, January 2013, pp. 320-327.

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F - Power Systems[F1] W. F. Davidson, “Sun-Spot Disturbances of Terrestrial Magnetism,” Electrical Engineering, Vol. 60, No. 2, February 1941, pp. 72-75.[F2] V. D. Albertson and J. M. Thorson, Jr., “Power System Disturbances During a K-8 Geomagnetic Storm: August 4, 1972,” IEEE Transactions on Power Apparatus and Systems, Vol. PAS-93, No. 4, July/August 1974, pp. 1025-1030.[F3] V. D. Albertson, J. M. Thorson, Jr., and S. A. Miske, Jr., “The Effects of Geomagnetic Storms on Electrical Power Systems,” IEEE Transactions on Power Apparatus and Systems, Vol. PAS-93, No. 4, July/August 1974, pp. 1031-1044.[F4] N. Mohan, J. G. Kappenman, and V. D. Albertson, “Harmonics and Switching Transients in the Presence of Geomagnetically-Induced Currents,” IEEE Transactions on Power Apparatus and Systems, Vol. PAS-100, No. 2, February 1981, pp. 585-593.[F5] Risto Pirjola, “On Currents Induced in Power Transmission Systems During Geomagnetic Variations,”IEEE Transactions on Power Apparatus and Systems, Vol. PAS-104, No. 10, October 1985, pp. 2825-2831.[F6] John G. Kappenman, Vernon D. Albertson, Daniel Soulier, Robert J. Ringlee, James R. Stewart, Philip R. Gattens, and Christopher C. Balch, “Effects of Geomagnetic Disturbances on Power Systems,” Panel Session, July 12, 1989, IEEE PES Summer Meeting, Long Beach, CA, July 9-15, 1989.[F7] P. R. Barnes, D. T. Rizy, B. W. McConnell, F. M. Tesche, and E. R. Taylor, Jr., “Electric Utility Industry Experience with Geomagnetic Disturbances,” ORNL-6665, Power Systems Technology Program, Oak Ridge National Laboratory, September 1991.[F8] A. P. Sakis Meliopoulos, George J. Cokkinides, and Mario Rabinowitz, “Comparison of SS-GIC and MHD-EMP-GIC Effects on Power Systems,” IEEE Transactions on Power Delivery, Vol. 9, No. 1, January 1994, pp. 194-207.[F9] D. H. Boteler, Q. Bui-Van, and J. Lemay, ”Directional Sensitivity to Geomagnetically Induced Currents of the Hydro-Quebec 735 kV Power System,” IEEE Transactions on Power Delivery, Vol. 9, No. 4, October 1994, pp. 1963-1971.

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[F10] D. H. Boteler and R. J. Pirjola, “Nature of the Geoelectric Field Associated with GIC in Long Conductors Such As Power Systems, Pipelines, and Phone Cables,” Proceedings of the 1997 International Symposium on Electromagnetic Compatibility, Beijing, China, May 21-23, 1997, pp. 68-71.[F11] Léonard Bolduc, Pierre Langlois, David Boteler, and Risto Pirjola, “A Study of Geoelectromagnetic Disturbances in Québec, 1, General Results,” IEEE Transactions on Power Delivery, Vol. 13, No. 4, October 1998, pp. 1251-1256.[F12] Ari Viljanen, “Relation of Geomagnetically Induced Currents and Local Geomagnetic Variations,”IEEE Transactions on Power Delivery, Vol. 13, No. 4, October 1998, pp. 1285-1290.[F13] Léonard Bolduc, Pierre Langlois, David Boteler, and Risto Pirjola, “A Study of Geoelectromagnetic Disturbances in Québec, 2, Detailed Analysis of a Large Event,” IEEE Transactions on Power Delivery, Vol. 15, No. 1, January 2000, pp. 272-278.[F14] Risto Pirjola, “Geomagnetically Induced Currents During Magnetic Storms,” IEEE Transactions on Plasma Science, Vol. 28, No. 6, December 2000, pp. 1867-1873.[F15] Risto Pirjola, Chun-ming Liu, and Lian-guang Liu, “Geomagnetically Induced Currents in Electric Power Transmission Networks at Different Latitudes,” Paper presented at the 2010 Asia-Pacific International Symposium on Electromagnetic Compatibility, Beijing, China, April 12-16, 2010.[F16] Trevor R. Hutchins and Thomas J. Overbye, “The Effect of Geomagnetic Disturbances on the Electric Grid and Appropriate Mitigation Strategies, “Paper presented at the 43rd North American Power Symposium, Boston, MA, August 4-6, 2011.[F17] “Geo-Magnetic Disturbances (GMD): Monitoring, Mitigation, and Next Steps; A Literature Review and Summary of the April 2011 NERC GMD Workshop,” North American Electric Reliability Corporation, Atlanta, GA, October 2011, http://www.nerc.com/files/GMD_Workshop_Report_April_2011.pdf.[F18] “Geomagnetic Effects on Pipelines,” Space Weather Canada, Government of Canada, November 22, 2011, http://spaceweather.ca/tech/pipelines/se-pip-eng.php.[F19] Ramsis Girgis, Emanuel Bernabeu, Frank Koza, David W. Fugate, and Bill Chiu, “Geo-Magnetically Induced Currents: Effects and the Power System; Monitoring, and Potential Mitigation,” Tutorial Session, March 15, 2012, IEEE PES Transformers Committee Spring 2012 Meeting, Nashville, TN, March 11-15, 2012.

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[F20] Randy Horton, David Boteler, Thomas J. Overbye, Risto Pirjola, and Roger C. Dugan, “A Test Case for the Calculation of Geomagnetically Induced Currents,” IEEE Transactions on Power Delivery, Vol. 27, No. 4, October 2012, pp. 2368-2373.

G - Power System Operations[G1] John G. Kappenman, “Geomagnetic Storm & Power System Impacts: Advanced Storm Forecasting for Transmission System Operations,” IEEE PES Summer Meeting, Edmonton, AB, July 18-22, 1999.[G2] John G. Kappenman, William A. Radasky, James L. Gilbert, and I. Arslan Erinmez, “Advanced Geomagnetic Storm Forecasting: A Risk Management Tool for Electric Power System Operations,” IEEE Transactions on Plasma Science, Vol. 28, No. 6, December 2000, pp. 2114-2121.[G3] “Procedures for Solar Magnetic Disturbances Which Affect Electric Power Systems,” Document C-15, Northeast Power Coordinating Council, Inc, New York, NY, Revised: January 11, 2007.[G4] “Industry Advisory, Preparing for Geo-Magnetic Disturbances,” A-2011-05-10-01, North American Electric Reliability Corporation, Princeton, NJ, Initial Distribution: May 10, 2011.[G5] “Implement Solar Magnetic Disturbance Remedial Action,” SOP-RTMKTS.0120.0050, Revision 14, ISO New England, Holyoke, MA, April 10, 2012.

H - Current Transformers & Protective Relaying[H1] J. G. Kappenman, V. D. Albertson, and N. Mohan, “Current Transformers and Relay Performance in the Presence of Geomagnetically-Induced Currents,” IEEE Transactions on Power Apparatus and Systems, Vol. PAS-100, No. 3, March 1981, pp. 1078-1088.[H2] B. Bozoki at al., Working Group K-11 of the Substation Protection Subcommittee of the Power System Relaying Committee, IEEE PES, “The Effects of GIC on Protective Relaying,” IEEE Transactions on Power Delivery, Vol. 11, No. 2, April 1996, pp. 725-739.[H3] Changyun Li, Qingmin Li, Jinxia Yao, and Min Liu, “The Characteristics of Electromagnetic Current Transformers with DC Bias,” Paper presented at the 1st International Conference on Sustainable Power Generation and Supply (SUPERGEN), Nanjing, China, April 6-7, 2009.

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I - HVDC Converters[I1] N. Mohan, V. D. Albertson, T. J. Speak, J. G. Kappenman, and M. P. Bahrman, “Effects of Geomagnetically-Induced Currents on HVDC Converter Operation,” IEEE Transactions on Power Apparatus and Systems, Vol. PAS-101, No. 11, November 1982, pp. 4413-4418.[I2] A. Sarshar, M. R. Iravani, and J. Li, ”Calculation of HVDC Converter Noncharacteristic Harmonics Using Digital Time-Domain Simulation Method,” IEEE Transactions on Power Delivery, Vol. 11, No. 1, January 1996, pp. 335-344.

J - Geomagnetically-Induced Current Monitoring[J1] J. D. Aspnes, R. P. Merritt, and B. D. Spell, “Instrumentation System to Measure Geomagnetically Induced Current Effects,” IEEE Transactions on Power Delivery, Vol. PWRD-2, No. 4, October 1987, pp. 1031-1036.[J2] Donald R. Fagnan, Phil R. Gattens, and F.D. Johnson, “Monitoring Solar Magnetic Disturbances in Power Systems (A Summary),” IEEE Power Engineering Review, November 1990, pp. 4-6.[J3] Ben Damsky, William Feero, Richard Pyle, and Ronald Henderson, “The SUNBURST Network: Recording and Analyzing Solar Magnetic Disturbances (Summary).” IEEE Power Engineering Review, November 1990, p. 6.

K – Other References[K1] J. E. Burbank, “Earth Currents and a Proposed Method for their Investigation,” Terrestrial Magnetism and Atmospheric Electricity, Vol. 10, No. 1, March 1905, pp. 23-49.[K2] New York Times, May 29, 1877, p. 5.[K3] New York Times, August 15, 1880, p. 8.[K4] New York Times, November 18, 1882, p. 1.[K5] Space Weather, May 13, 1921 - The New York Railroad Storm, http://www.solarstorms.org/SS1921.html.[K6] Central Station Engineers of the Westinghouse Electric Corporation, Electrical Transmission and Distribution Reference Book - 4th Edition, Westinghouse Electric Corporation, East Pittsburgh, PA, 1950.

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IEEE PES Boston Chapter & IEEE Com Soc Boston Chapter�Joint Lecture��Space Weather in Solar Cycle 24:�Is the Power Grid at Risk?AcknowledgementsPresentation OverviewEarly Man-Made Electromagnetic SystemsTelegraphyTelephonyRadio TelegraphyRailroad SignalingA Correlation of Sunspot Activity &�Major Electrical System Disturbances Induction Of Geomagnetic CurrentsEarth Conductivity In US & CanadaProbability Of Geomagnetic Storms In�US & CanadaPath Of Geomagnetically-Induced Currents In Electric Power SystemsFirst Order Effect On Power Systems Of Geomagnetically-Induced Current Normal Power Transformer Magnetic StatePower Transformer Equivalent Circuit –�Normal Core MagnetizationSingle Phase Transformer�With Three-Legged CoreTransformer With Normal Magnetic Field�(Core Not Saturated)Effect Of Geomagnetic (Low Frequency) Currents On Power TransformersPower Transformer Equivalent Circuit –�Saturated Core MagnetizationTransformer With Leakage Flux�(Core Saturated)Second Order Effects On Power Systems Of Geomagnetically-Induced Current Transformer Winding Failure Due To Localized Abnormal HeatingShunt Reactors & Shunt CapacitorsInductive & Capacitive ReactanceAbnormal Reactance Effects On�Power Systems During Geomagnetic EventsEffects On Current Transformers (CT’s)�During Geomagnetic EventsProtective RelaysEffects On Protective Relays�During Geomagnetic EventsEvent Of August 4, 1972 {1}Event Of August 4, 1972 {2}Event Of March 13, 1989 {1}Event Of March 13, 1989 {2}Mitigation Strategies {1}Mitigation Strategies {2}Slide Number 36ReferencesReferencesReferencesReferencesReferencesReferencesReferencesReferencesReferences