this was created for submit in one of my campus assesment!
Roshan Karunarathna (rosh@vau.jfn.ac.lk)
1. INTRODUCTION
The sun’s magnetic and sunspot cycles have being expected to get peak from 2013, bringing a stormy season to our solar system and an increase in sun related damage here on Earth. - Power networks, pipelines, radio communications and the global positioning system (GPS) are all entering a period of increased risk of outages from geomagnetic storms as the solar activity cycle peaks in 2013.
Our sun is a massive ball of superheated gases that swirl with incredible currents and magnetic fields. At times the pressure builds up into sunspots, which can explode out from the sun in events known as solar flares, solar proton events (SPEs) and coronal mass ejections (CMEs).
2. IMPACT OF SOLAR STORMS
Solar events happen all the time, but 2013 was predicted to be a particularly bad year due to the peaking of several sun cycles. The last time this happened was in 1859 when the largest recorded solar storm spun compasses, disrupted telegraph service, and lit up the skies. Our dependency on electronics and an overloaded power grid makes us much more vulnerable to solar storms today.
“Solar storms” bombard the solar system – and Earth – with radiation and magnetic shock waves that can wreak havoc on magnetic fields, power systems, and electronics devices. The Earth’s atmosphere shields us from much of the radiation, but solar storms can still do quite a bit of damage, including:
• Short out satellites and take down GPS, cell phone, Internet, and TV services.
• Cause damage to electronic devices and computers.
• Disrupt the power grid resulting in overloads, widespread power outages, and dangerous power surges. • Increase corrosion and breakage of gas and fuel pipelines.
• Confuse compasses and electromagnetic gadgets.
• Cause light displays (like the “northern lights”) in the sky.
• Knock out communications, including radio, military communications, and early warning systems.
3. IMPACT OF SOLAR STORMS ON COMMUNICATION NETWORK
Solar storms can affect radio communications, satellite communications, radars and navigation systems. When consider about effect on communications, in the past solar storms have caused billions of dollars of commercial satellites to malfunction and die prematurely. A Great solar storm has the power to destroy many space assets (Space Station, Space Shuttle, LEO Satellites, GEO Satellites, and Off World Missions) simultaneously.
3.1 RADIO COMMUNICATION
On frequencies below 30MHz, the ionosphere generally acts as an efficient reflector, allowing communications to distance. Solar extreme ultraviolet and soft x-ray emissions from solar flares change the electron density and gradients in the ionosphere reflections. A sudden increase of x-ray radiation from a solar flare causes substantial ionization in the lower region of the ionosphere producing ionospheric disturbances of radio signals, sudden phase anomalies, sudden enhancement of signals and short wave fade. Solar flares also produce a wide spectrum of radio noise (Cohen N and et al., 1994).
Polar cap absorption (PCA), aurora absorption, multipatting and non-great circle propagation effects are associated with coronal mass ejections (CMEs) that can disrupt radio communications. The effects of solar storms on radio communications through ionospheric reflectivity and scintillation include (NSSA, 2007, Barnes, P.R and et al., 1991)
3.2 SATELITE COMMUNICATION
In our technology driven society, satellites play an important role in communications. The loss of satellites can affect: major news wire service feeds, network television, satellite Television and cable programming, nationwide radio service, weather data, cell phone service, pagers, automated teller machines, gas station credit card handling services, airline weather tracking services, earthquake monitoring network, blackberries, GPS navigation service, and critical military & airline communications. And this list grows longer every day.
Current commercial satellites are light-weight, sophisticated, built at the lowest cost using off-the- shelf electronics. This current low cost approach makes new satellite design more vulnerable to damage from solar storms due to less radiation hardening. A high-energy particle from an SPE can penetrate the wall of a satellite and deposit sufficient charge to cause an electrical upset to a circuit switch, false command, memory state change or loss. As the nuclear particles collide within the spacecraft, they release electrons that build up an internal dielectric charge. This static charge can destroy circuitry on electronic boards. The particles can also change data and instructions stored in computer memory. Some of the memory damage is soft causing Single Event Upset (SEU). Generally, this anomaly can be corrected by a computer reboot. But some of the damage can be hard causing unrepairable physical damage to the junction of the microcircuit. These types of failures can be fatal. Satellites receive their operating power from large solar panels arrays. High-energy protons from SPEs and CMEs can damage the solar cells by causing the silicon atoms in the solar cell matrix substrate to violently shift position which produce crystal defects. These defects increase the resistance of the solar cells to electrical current. As a direct result, solar cell efficiency steadily decreases and solar panel power drops off.
One critical satellite system that is very sensitive to damage from solar storms is the Attitude Control System. If the system is damaged or compromised, the satellite will become disoriented. Without accurate orientation data, the satellite will be unable to make fine adjustments to its orbit to prevent the satellite from reentering Earth’s atmosphere and burning up.
Another threat is differential charging. Charged particles striking different areas of a spacecraft can cause these sections of the spacecraft to be charged to different levels.
3.3 SUMMARIZED EFFECTS CONSIDERING DIFFERENT ASPECTS
• HF Radio Communication(3.3.MHz)
o Increased absorption.
o Depressed maximum usable
frequencies (MUF).
o Increased fading and flutter
o Effect short–wave propagation
through sunlit side of earth.
• VHF propagation (30 – 300MHz)
o Effect pagers and cellular phones
o Susceptibility to fadeout of the high and low band in mobile voice communications for
dispatching utility company line crews
• Satellite communications (200MHz to several GHz)
o Increased scattering of satellite- to-ground ultra-high frequency (UHF) transmissions or
scintillation can seriously interfere with direct satellite communications links
• Radio frequency interfere (RFI)
o Loss of phase lock
o Severe distortion of data
transmissions from
geosynchronous satellites
o Erroneous positioning information from single frequency GPS
o Drastic loss in spacecraft electrical power due to inability to reposition craft.
o Faraday rotation of the plane of polarization effect on satellites that employ linear polarization up to 1GHz
• Radar surveillance systems
o Azimuth angle errors
o Range errors
o Radar energy scatter due to
auroral interference
o Elevation angle errors
• Navigation systems
o position errors
o Scintillation of GPS signals
o Inaccuracy due to the
introduction of small delays
from GPS satellite signals
o fadeout of signals
4. PREVENTIVE MEASURES
Having analyzed the threats that can be caused by solar storms upon the improved technologies being enjoyed today, it is necessary to highlights measures to mitigate them. So protecting Network Communication systems is also got a vital importance due to the reason modern world is depend on such technologies mostly. These precautionary measures include but not exhaustive of the following:
o Use of series capacitors to block the flow of GIC in transmission lines or neutral – blocking capacitors in transformer neutrals.
o Putting sunscreen on all technology.
o Replacement of copper wires with optical fibers by telecommunications operators
o Installation of solar storm warning system (solar monitor) that can offer up to date information on solar activity, including images, flares locations, flare predictions.
o Use of shorter transmission cables as they are less vulnerable to damage.
o Long term preventive measures also exist to protect against coronal mass ejections, including digging transmission cables into the soil, placing lighting rods on transmission wires, reducing operating voltages of transformers and using cables that are shorter than 10 kilometers. It might also be possible to develop and deploy large resistors that would add another level of protection to large transformers.
o Incorporating solar storm hardening into satellite design.
o By receiving geomagnetic storm alerts and warning (e.g. by the space weather prediction center, via space weather satellites), power companies can minimize damage to power transmission equipment by momentarily disconnecting transformers or by inducing temporarily blackouts.
4.1 PREPARING FOR OUTAGES
The biggest threat of a solar super storm is a knockout of the power and communications grids that might take some time to repair. You can prepare for this the way you’d prepare for any kind of storm, by stocking up on:
Off the Grid Power: Buy a generator and extra fuel, or install a backup energy supply such as solar panels or a wind turbine.
Battery Backup for Computers: An Uninterrupted Power Supply (UPS) looks a lot like a standard surge protector but contains batteries that keep computers running smoothly without damage during power fluctuations and brownouts.
Emergency Supplies: Create an emergency box with flashlights, batteries, cooking and heating fuel, food, and clean water. Also, consider a backup stash with paper copies of financial and personal records, cash, road maps, address book, radio, first-aid kit, and anything else you’d need if your handy digital gizmos – along with your car, credit cards, bank, and shopping center – are out of commission for a while.
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| Figure 1.Portable generator |
Preparing for Power Surges
Likewise, a powerful solar storm may cause major power surges that might fry anything in its path. Protect your electronics by using:
1. Whole House Surge Protector: A whole house surge protector connects to your breaker panel and provides protection from lightning and other power surges.
2. Individual Surge Protectors: For added protection, or in the absence of a whole house surge protector, install surge protectors on computers, TVs, stereos, and other electronics in your home.
5 SUGGESTED SYSTEMS AND SOLUTIONS FOR A SECURE COMMUNICATION NETWORK SYSTEMS
5.1 "SOLAR SHIELD" COULD HELP KEEP”THE LIGHTS ON”TO HAVE A CONTINUE
POWER OVER DEVICES.
"Solar Shield is a new and experimental forecasting system”. We can zero in on specific transformers and predict which of them are going to be hit hardest by a space weather event. The troublemaker for power grids is the "GIC" – short for geomagnetically induced current. When a coronal mass ejection (a billion-ton solar storm cloud) hits Earth's magnetic field, the impact causes the field to shake and quiver
During extreme storms, engineers could safeguard the most endangered transformers by disconnecting them from the grid. That itself could cause a blackout, but only temporarily. Transformers protected in this way would be available again for normal operations when the storm is over. The innovation of Solar Shield is its ability to deliver transformer-level predictions.
How it works:
Solar Shield springs into action when we see a coronal mass ejection (CME) billowing away from
the sun. Images from SOHO and NASA's twin STEREO spacecraft shows the cloud from as many as three points of view, allowing to make a 3D model of the CME, and predict when it will arrive.
While the CME is crossing the sun-Earth divide, the Solar Shield team prepares to calculate ground currents. The crucial moment comes about 30 minutes before impact when the cloud sweeps past ACE, a spacecraft stationed 1.5 million km upstream from Earth. Sensors onboard ACE make in situ measurements of the CME's speed, density, and magnetic field. These data are transmitted to Earth and the waiting Solar Shield team.
Computer models predict fields and currents in Earth's upper atmosphere and propagate these currents down to the ground." With less than 30 minutes to go, Solar Shield can issue an alert to utilities with detailed information about GICs.
This idea of Solar Shield is experimental and has never been field-tested during a severe geomagnetic storm. A small number of utility companies have installed current monitors at key locations in the power grid to help the team check their predictions.
5.2 EARLY WARNING SYSTEM
Geomagnetic storms are triggered when a billion tones or more of solar plasma erupts from the surface of the sun at speeds of up to 3,000 kilometers per second, in what is known as a coronal mass ejection (CME).
If the mass ejection occurs in the direction of Earth, it can interact with the planet's own magnetic field and induce a substantial voltage on the surface. Long man-made conducting paths such as transmission lines, metallic pipelines, cables and railways act as antennae, focusing and transferring the current.
But CMEs are difficult to predict. They often batter Earth about four to five days after a solar flare is observed, but not always. The Advanced Composition Explorer (ACE) satellite, stationed a million miles from Earth, can detect the intensity of an incoming storm but may give as little as 30 minutes warning of its arrival. Forecasters issue a Sudden Impulse Warning, which indicates the Earth's magnetic field will soon be distorted by an incoming geomagnetic disturbance.
Demand for solar weather predictions and warnings has grown rapidly from operators of power, communications and navigation systems and airlines, but the crucial ACE satellite is aging and nearing the end of its useful life.
5.3 NETWORK SECURITY SYSTEM
5.3.1 USING POWER SURGE PROTECTORS
The devices should be protected with power surge protectors. After a situation, all grids have procedures for a "black start" following complete collapse: first by starting up specialist diesel generators, re-energizing selected power plants, connecting them to the grid, then gradually bringing the rest of the power generating sets back online and gradually restoring power to customer’s one area at a time. Less likely (but much more damaging) would be if a storm caused some of the extra-high voltage (EHV) transformers on the network to overheat and burn out. Most networks have only limited supplies of EHV transformer components, and there would be long lead-times for designing, manufacturing and installing new ones.
If a large number of transformers were fried, it might take months to restore power, according to a report on the "Effects of Geomagnetic Disturbances on the Bulk Power System" published by the North American Electric Reliability Corporation (NERC) in February 2012.
5.3.2 ACT WHEN TRANSMISSION IS IN HIGH DEMAND
Risks to the network and transformers are heightened when power lines and transformers are operating close to capacity. The biggest danger comes in spring and autumn, when a relatively small number of power plants are operating and transmission is in high demand. The simplest way to safeguard the network is to cut the demand for transmission, which lowers the operating temperature of the transformers so they have more room to rise safely without causing permanent damage. Grid operators can cut pressure on the network by increasing the amount of local generation (calling up more units from standby). In extreme cases, customers' power can be disconnected. Better a temporary loss of supply than one that lasts for months. Upgrading to newer and more reliable transformers can also harden the network against the risk of burn-out and failure.
Interest in space weather prediction is rising. The hope is that even a few minutes’ notice about an incoming storm at level G4 or G5 could allow networks to move to a safer operating mode or temporarily shut down as a precaution.
REFERENCES..
Web References…
1. http://www.space.com/713-space-storm-hits-earth-survives.html
2. http://www.solarstorms.org/SWChapter1.html
3. http://www.todayshomeowner.com/how-to-protect-your-home-from-solar-flares- and-solar-storms/
4. http://science.nasa.gov/science-news/science-at-nasa/2010/26oct_solarshield/
5. http://www.solar-facts-and-advice.com/coronal-mass.html
Papers….
1. Impacts of solar storms on energy and communications technologies
*Omatola, K.M. and Okeme, I.C.
Department of Physics, Kogi State University, Anyigba, Nigeria
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