The document discusses the effects of geomagnetic storms on power systems. Geomagnetic storms are caused when coronal mass ejections from the sun interact with the Earth's magnetosphere. This interaction can induce geomagnetically induced currents in long-distance power lines that can cause equipment damage, power outages, and blackouts. Key impacts include transformer heating, damage from harmonic currents, increased reactive power consumption, and protection system malfunctions. Case studies of historical geomagnetic storms that caused power outages are presented. Approaches to mitigate risks include installing blocking devices, power flow management, and load shedding.

1. 10EES86 Electrical and Electronics Engineering
The Effects of
Geomagnetic Storms on
Power Systems
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1DS12EE002

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INTRODUCTION

3. Introduction
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 During geomagnetic storms we are evaluating the health of
Power System equipment.
 Studying the effects of geomagnetic Storm, provides the
measures to protect the equipment.
 Increases the reliability of power supply system as reduces
risk to the equipment and avoid outages, during Geomagnetic
Strom.

4. Definitions
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 Space Weather
Geomagnetic storms, sub storms, and auroras produced by ionized
particles captured in the Earth’s magnetic field.
 Solar Wind
Motion of interplanetary ionized particles away from the Sun and
towards the Earth.
 Magnetosphere
Magnetic field of Earth ,extends into space.

5. Coronal Mass Ejection (CME)
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 Produced by large flares.
 Cloud of solar material (Charged particles)and magnetic
fields, ejects from the sun.
 Cause storms on earth several days after leaving the sun.
 Speed : 1 to 5 million miles per hour
 Electrons, coronal and solar wind ions
 Mass : Up to 1 billion metric tons
 Temperature : > 1 million Kelvin
 Width : Millions of km

6. Coronal
Mass
Ejection
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7. What is a
Geo-
magnetic
storm?
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 Caused when Earth directed CME, collide
with Earth’s magnetosphere.
 11-year cycles
 Variations
 Duration (10s – several days)
 Daytime v. Nighttime
 Size
 Frequency
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8. Normal
Earth’s
Magnetic
Field
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9. GEO MAGNETIC SPACE STORM
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CME
Distorted Earth’s Magnetic Field

10. What is a
Geo-
magnetic
Induced
Current?
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 CME interact with Earth’s magnetosphere-
ionosphere.
 Produce ionospheric currents, called Electro-
jets.
 Typically millions of amperes in magnitude.
 Electro-jets penetrate Earth’s geomagnetic
field, inducing voltage potential at Earth’s
surface and resulting in GICs.
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11. Geo-
magnetic
Induced
Current
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12. Solar Activity A Index level K Index level
Quiet A Index <7 Usually no K-indices >2
Unsettled 7< A Index <15 Usually no K-indices >3
Active 15< A Index <30 A few K-indices of 4
Minor Geomagnetic Storm 30< A Index < 50 K-indices mostly 4 and 5
Major Geomagnetic Storm 50< A Index <100 K-indices mostly 5 and 6
Severe Geomagnetic Storm A Index >100 K-indices 7 or greater
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A-Index
The A-index is based on the data from a set of specific stations after
observing the storm for 24 hour at a mid-latitude observatory.

13. What is a
Kp-
index?
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 Based on A-index.
 The Kp-index quantifies
disturbances in the horizontal
component of earth's magnetic field
 An integer in the range 0-9.
 Being 1 is calm and 5 or more
indicating vigorous geomagnetic
storm.
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14. Kp Index NOAA Space Weather Scale Geomagnetic Storm levels
Kp = 5 G1 (Minor)
Kp = 6 G2 (Moderate)
Kp = 7 G3 (Strong)
Kp = 8 G4 (Severe)
Kp = 9 G5 (Extreme)
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Kp-INDEX

15. Impacts the GMD
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 Affect Power System
 Satellite malfunction
 Radio transmission disruption
 High altitude aircraft damage
 Relay mis-operation

16. Impacts on Power System
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 Disrupts power grids
 Blackouts
 Damage to the transformers
 Damage to the Generators
 Damage to the Circuit Breaker
 Reduce system voltage lead to power outage.
 Consume more reactive power
 Trip capacitor banks
 Loss of reactive power support.

17. Degree of impact by a GMD storm on power
system based on factors:
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 Magnitude of the magnetic field and its orientation.
 Latitude
 Directional orientation, resistance, and length of transmission
lines.
 Geology of local area like the electrical conductivity of soil.
 Proximity of the ocean or the large water bodies.
 Design of power system and power system equipment.

18. Case Studies:
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 March 13, 1989
Hydro Quebec power system collapsed by G5 storm
Collapsed in 90 seconds
Restoration took 9 hours
6 million customers lost power
Total cost to Quebec: $13.2 million
Transformer heating problems (1,200 MVA transformer destroyed)

19. Case Studies…
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 July 15, 2000
G5 Class geomagnetic storm
Kp of 9 for over nine hours
No significant power system damage
 March 1989 GMD storm
Failure of the Salem No.-1 Nuclear
Generator.
Circulating currents in low-voltage
windings of transformer.

20. Interaction with Power System :
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21. Effects of
GIC in an
HV
Transmission
Network
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22. Approach
to
GMD risk
mitigation
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Effects on
Power System Equipments

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GENERATORS
Negative Sequence Current due to GIC cause
 Voltage imbalance and harmonic distortion by GSU
transformer impact the generator.
 Failure due to rotor heating and protective relay operation.
 Increased Generator heating.
 Negative sequence relay alarming mis-operation.

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GENERATORS
 Damage to rotor rings and wedges, by negative sequence
current and rotor heating
.
 Increased mechanical vibrations and torsional stress.

26. Mitigation technique to Protect Generator
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 Reduce power output to increase margin in rotor field amps
and allowable rotor heating.
 Reduce loading on a per generator basis and Increase local
reactive power capacity.
 Ensure that allowable negative sequence current is maintained
within IEEE limits.

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CIRCUIT BREAKERS
 If magnitude of GIC exceeds the peak of current to be
interrupted during a fault, the arc between the poles of circuit
breaker would not be interrupted and damage the circuit
breaker.
 If magnitude of GIC is small, current interruption will always
takes place at zero crossing.
CONDUCTORS
GIC impact line sag and conductors temperature when the circuit
is stressed to severe GMD events.

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TRANSFORMERS
Effects of GICs on EHV Transformer
 Harmonic Currents
Cause relays to trip working equipment.
 Fringing magnetic field (flux that flows outside the core)
Create heating in Transformer which, reduced life.
 Increased reactive power (VAR) consumption
VAR consumption can cause the system to collapse due to
voltage instability.

29. TRANSFORMER PROTECTION
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 Current limiting capacitance (i.e., powerful capacitor)
In the transformer’s neutral transmit alternating current of
the mains’ frequency under normal operation but block the
flow of the low-frequency GIC.
 Special protective relay
Contains no microelectronic components ,based on high-
voltage elements to resist electromagnetic interferences.

30. Conclusion
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 Our GIC measurement shows observed GIC almost in
proportion to variations in the geomagnetic field.
 Technologies will be helpful in predicting GIC when a major
geomagnetic storm occurs.
 Mitigation strategies will be explored: transformer bypassing,
installing of GIC blocking devices, power flow redistribution
by intentional line outages, and load shedding schemes, to
name a few.

31. REFERENCES
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1. “The effects of geomagnetic storms on electrical power
systems” IEEE Power System excessive harmonic currents in
the ground relays.4 Communications Committee of the
IEEE Power Engineering Society.
2. “Serbian journal of electrical engineering” ,Vol. 8, No. 2,
November ,2011.
3. GMDTF Interim Report: “Affects of geomagnetic
Disturbances on the bulk power system”- February 2014.

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Thanks

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