Transmission is made of a high electromotive force web, by and large 110 - 765 kilovolt Ac. The higher the electromotive force degree of a transmittal line, the lower is the transmittal power loss. However, the electromotive force bounds for the transmittal line electromotive forces are set by insularity and protective devices.
The standard transmittal line electromotive forces depend upon the state and they are: 765, 550, 500, 400, 345, 275, 230, 169, 145, 132, 110, 66, 33 kilovolt. The electromotive forces in the scope of 345 - 765 kilovolts are classified as excess high electromotive force (EHV). The electromotive forces above 765 kilovolts are considered as extremist high electromotive forces (UHV). Presently, the UHV systems, at 1000-, 1500-, 2250- kilovolt electromotive force degrees are in research phase. Point to indicate transmittal is, some clip, preferred by HVDC. The electromotive force degrees used for HVDC power transmittal are: 250 kilovolt, 400 kilovolt, 500 kilovolt and 550 kilovolt. Higher District of Columbia electromotive forces are being planned.
National Grid Malaysia is the chief electricity transmittal web associating the electricity coevals, transmittal, distribution and ingestion in Malaysia. It is operated and owned by Tenaga Nasional Berhad (TNB) . The transmittal line electromotive forces for Malaysia are running at 132kV, 275kV and 500kV.
Other than grid system, Malaysia besides has a High Voltage Direct Current Transmission line where the 300 MW Thailand - Malaysia HVDC interconnectedness system consists of Khlong Ngae convertor station on the Thai boundary line and Gurun convertor station on the Malaysia boundary line. Both Stationss are linked by a 300 KV DC overhead transmittal line of 110 kilometer. EGAT 's Khlong Ngae convertor station is situated at Sadao territory in Southern Songkhla state, approximately 24 km. from Thai-Malaysia boundary line. TNB 's Gurun convertor station is located in Kedah, approximately 86 kilometers. from Malaysia 's northern boundary line. Malaysia will purchase electricity during the twenty-four hours clip for our commercial use which is Malaysia 's Peak use and Thailand will purchase during the eventide boulder clay tardily dark where their use is at the extremum.
History of Use
In the early years of commercial usage of electric power, transmittal of electric power at the same electromotive force as used by illuming and mechanical tons restricted the distance between bring for thing works and consumers. Originally coevals was with direct current, which could non easy be increased in electromotive force for long-distance transmittal. Different categories of tons, for illustration, illuming, fixed motors and grip (railroad) systems, required different electromotive forces and so used different generators and circuits.
The alleged "cosmopolitan system '' used transformers both to twosome generators to high-potential transmittal lines, and to link transmittal to local distribution circuits. By a suited pick of public-service corporation frequence, both illuming and motor tons could be served. Rotary convertors and subsequently mercury-arc valves and other rectifier equipment allowed DC burden to be served by local transition where needed. Even bring forthing Stationss and tons utilizing different frequences could besides be interconnected utilizing rotary convertors. By utilizing common bring for thing works for every type of burden, of import economic systems of graduated table were achieved, lower overall capital investing was required, load factor on each works was increased leting for higher efficiency, letting for a lower cost of energy to the consumer and increased overall usage of electric power.
By letting multiple bring forthing works to be interconnected over a broad country, electricity production cost was reduced. The most efficient available works could be used to provide the varying loads during the twenty-four hours. Reliability was improved and capital investing cost was reduced, since stand-by bring forthing capacity could be shared over many more clients and a wider geographic country. Remote and low-priced beginnings of energy, such as hydroelectric power or mine-mouth coal, could be exploited to take down energy production cost.
The first transmittal of three-phase jumping current utilizing high electromotive force took topographic point in 1891 during the international electricity exhibition in Frankfurt. A 25 kilovolt transmittal line, about 175 kilometers long, connected Lauffen on the Neckar and Frankfurt.
Voltages used for electric power transmittal increased throughout the twentieth century. By 1914 55 transmittal systems running at more than 70,000 V were in service, the highest electromotive force so used was 150,000 Vs. The first three-phase jumping current power transmittal at 110 kilovolts took topographic point in 1912 between Lauchhammer and Riesa, Germany. On April 17, 1929 the first 220 kilovolt line in Germany was completed, running from Brauweiler near Cologne, over Kelsterbach near Frankfurt, Rheinau near Mannheim, Ludwigsburg-Hoheneck near Austria. The masts of this line were designed for eventual ascent to 380 kilovolt. However, the first transmittal at 380 kilovolt in Germany was on October 5, 1957 between the substations in Rommerskirchen and Ludwigsburg-Hoheneck. In 1967 the first extra-high-voltage transmittal at 735 kilovolts took topographic point on a Hydro-Quebec transmittal line. In 1982 the first transmittal at 1200 kilovolt was in the Soviet Union.
The rapid industrialisation in the twentieth century made electrical transmittal lines and grids a critical portion of the economic substructure in most industrialised states. Interconnection of local coevals workss and little distribution webs was greatly spurred by the demands of World War I, where big electrical generating workss were built by authoritiess to supply power to weaponries mills ; subsequently these workss were connected to provide civil burden through long-distance transmittal.
Small municipal electrical public-service corporations did non needfully want to cut down the cost of each unit of electricity sold ; to some extent, particularly during the period 1880-1890, electrical lighting was considered a luxury merchandise and electric power was non substituted for steam power. Engineers such as Samuel Insull in the United States and Sebastian Z. De Ferranti in the United Kingdom were instrumental in get the better ofing proficient, economic, regulative and political troubles in development of long-distance electric power transmittal. By debut of electric power transmittal webs, in the metropolis of London the cost of a kilowatt hr was reduced to tierce in a ten-year period.
In 1926 electrical webs in the United Kingdom began to be interconnected in the National Grid, ab initio runing at 132,000 Vs.
Hazard Posed by High Voltage Power Lines
The hovering electric and magnetic Fieldss in electromagnetic radiation will bring on an electric current in any music director through which it passes. Strong radiation can bring on current capable of presenting an electric daze to individuals or animate beings. It can besides overload and destruct electrical equipment.
Electrocution Hazards Working Near Overhead Power Lines
Most overhead power lines are n ot insulated.Activities conducted near overhead powerlines such as: threading communicating wiring ; raising antenna masts ; mounting in trees and onto edifices ; and utilizing portable metal ladder presents a existent danger
Highly high power electromagnetic radiation can do electric currents strong plenty to make flickers when an induced electromotive force exceeds the breakdown electromotive force of the environing medium. These flickers can so light flammable stuffs or gases, perchance taking to an detonation. This can be a peculiar jeopardy in the locality of explosives or pyrotechnics, since an electrical overload might light them. This hazard is normally referred to as RadHaz or HERO ( Hazards of Electromagnetic Radiation to Ordnance ) .
The best understood biological consequence of electromagnetic Fields is to do dielectric warming. For illustration, touching an aerial while a sender is in operation can do terrible Burns.
This warming consequence varies with the frequence of the electromagnetic energy. The eyes are peculiarly vulnerable to RF energy in the microwave scope, and prolonged exposure to microwaves can take to cataracts. Each frequence in the electromagnetic spectrum is absorbed by populating tissue at a different rate, called the specific soaking up rate or SAR, which has units of Watts per kg ( W/kg ) . The IEEE and many national authoritiess have established safety bounds for exposure to assorted frequences of electromagnetic energy based on SAR.
There are publications which support the being of complex biological effects of weaker non-thermal electromagnetic Fieldss, including weak ELF magnetic Fieldss and modulated RF and micro-cook Fieldss. Cardinal mechanisms of the interaction between biological stuff and electromagnetic Fieldss at non-thermal degrees are non to the full understood..
Environmental effects from transmittal lines can be found merely near to the line. Biological effects from electrical and magnetic Fieldss around the line have been intensively discussed during the last twosome of old ages.
Certain research surveies show fringy inauspicious wellness effects on human existences. Other surveies do non corroborate these effects.
Pollutant aerosols under high Voltage Power Lines
A probe of theoretically and by experimentation conducted at H.H Wills Physics Laboratory University of Bristol to measure the increased exposure to airborne pollutants near power lines. Harmonizing to Fews (1999), exposures were carried out at different power line location in assorted conditions and the exposure are taken along a line at a right angles up to 200m from a figure of high electromotive force power transmittal line. The consequence of the theoretical account predicts a two of three fold addition in deposition of aerosols on spherical surfaces miming the human caput under high electromotive force lines. This status applies when pesticides or other chemical are sprayed below the power line, the aerosols conditions will formed and do more risky conditions.
As referred to Bonneville Power Portland, vehicles parked under some high electromotive forces lines, vehicles can be roll up an induced electromotive force if the vehicle is parked on a nonconducting surface such as asphalt or dry lock. It will make flickers or worst electricity in your auto as it is non grounded. A individual will be electrocuted, when he or she is used as a music director to anchor the electromotive force induced.
Lightning will normally strike the highest nearby object, which might be a power line tower or wire. Transmission facilitates are designed to defy lightning work stoppages by imparting them to land at the tower.
Death can happen as a individual 's organic structure provides a way for current flow doing tissue harm and bosom failure. Other hurts can include Burns from the discharge generated by the inadvertent contact. These can be particularly unsafe if the victims air passages are affected. Injuries may besides be suffered as a consequence of the physical forces exerted as people may fall from tallness or be thrown considerable distance.
Tall object such as trees and turning flora at high electromotive force lines is risky at 2 facets. First is the semen in contact with the a transmittal line will take to closing down that line and upset the flow of electricity. Second trees and flora can carry on electricity, a state of affairs that can endanger people around the country, animate beings and belongings. The trees can basically go electrified and injured people touches it and might wound or even kill the individual.
Electricity can even leap or curve from the transmittal line up to 15 pass off between the power lines and flora. For this intent a 25 pess safety zone is implemented by Bonneville Power (2008) utilizing the article "Keeping the manner clear for safe and dependable service ''
Malaysia as equator and tropical conditions is full of Vegetation and trees in the surrounding of the transmittal lines. Therefore this is really risky in the Malaysia evidences.
Trespassing and hooliganism have been one of the chief issues in Malaysia where 1000000s of ringgit needed to replace and mend the amendss cause by unwanted activities mentioned. Steel beam and other parts of the tower and transmittal lines were taken down by larceny has been a really alarming.
Pools or pools should be situated near or under the transmittal line because it impedes the workers abilities to run and keep the power lines and presents a possible safety jeopardies to the populace. The jeopardy scope from possible electrical contact with the iwres to dangers that can be brushes during and after lightning work stoppage on transmittal installations. These conditions could be seen at the transmittal lines across paddy Fieldss at the province of KEDAH.
Reason why High Voltage Power Line is Still Use
Most of the high electromotive force power line usage overhead lines, but the power distribution within the metropolis or crowded topographic points is done utilizing belowground overseas telegrams. Less than one per centum of the entire transmittal lines are placed underground. Although belowground ac transmittal would show a solution to the environmental and aesthetic jobs involved in overhead lines, there are proficient and economical grounds that make the usage of belowground Ac transmittal prohibitive. For low electromotive force distribution applications there are no proficient jobs in utilizing overseas telegrams. The aesthetic and safety demands override the economical considerations in most of the distribution systems and therefore the belowground overseas telegrams are constantly used.
High electromotive force power line building is much less expensive than belowground transmittal. Bare wires are used in overhead lines with insularity employed at the points that the wire is supported. Wood or galvanized steel towers are used to back up the music directors. The dielectrics at the music director support points are normally ball and socket porcelain or fiberglass rods covered with skirts made of a compound similar to silicon gum elastic. Lines are good protected against lightning with lightning arresters and shield wires. Bundled music directors are used for 230 kilovolts and above to cut down line reactance and corona effects. There is a trade off between the line losingss and the cost of building the line. Lowering the I2R losings normally means larger music directors at higher electromotive force operation. This increases the cost of music directors and back uping tower cost. Therefore, the decrease in line loss must be carefully weighed against increased cost.
Underground lines are most normally used to feed urban substations in high burden denseness countries. The highest belowground transmittal line electromotive force is 525 kilovolt. Since the cost of an belowground line is 9 to 15 times the cost of an overhead line they are installed merely when they offer a clear advantage or there is no option.
The grounds for the high cost are:
EHV insularity is expensive.
The overseas telegrams must be installed in pipes made of steel or bronze which is dearly-won.
Proper chilling with oil circulation is required.
Difficult to turn up the mistake and expensive to mend.
The overseas telegrams are constructed with oil impregnated paper insularity in many beds. The overseas telegram has a coiling metal wire lesion around the exterior of the insularity to forestall harm to the overseas telegrams while putting. The full overseas telegram is covered with a thin lead sheath that keeps the oil impregnation in the insularity. After the overseas telegram is installed, the pipe is filled with oil. The oil is pumped through the pipe to chill every bit good as insulate the overseas telegram. The oil circulation system includes pumps, filters and oil armored combat vehicles. Sulpher hexaflouride (SF6) is some times used to insulate belowground transmittal overseas telegrams. The popularity of SF6 is increasing because of its simpleness. The belowground transmittal lines are more dependable if decently installed.
Adverse consequence that high electromotive force on homo, animate beings, and environment
Consequence on Human
The preponderance of grounds shows that the low power low frequence electromagnetic radiation associated with family current is really safe, and no biophysical theories for the induction or publicity of malignant neoplastic disease have been substantiated, some research has implicated exposure in a figure of inauspicious wellness effects. These include, but are non limited to, childhood leukemia ( mentions at a lower place ) , grownup leukemia, and neurodegenerative diseases.
Leukaemia and malignant neoplastic disease
Harmonizing to a case-control survey conducted in United Kingdom peculiarly in England and Wales, there is an association between childhood leukemia and propinquity of place reference at birth to high electromotive force power lines and the evident hazard extends to greater distance than would hold been expected. About 4 % of kids in England and Wales live within 600meter of high electromotive force lines at birth. If the association is causal, approximately 1 % of childhood leukemia in England and Wales would be properties to these lines though this estimation has considerable statistical uncertainness.
A United Kingdom survey of 29,000 instances of childhood malignant neoplastic disease, including 9700 instances of leukemia, found a rise hazard of childhood leukemia in kids who lived within 200m of high electromotive force lines at birth compared with those who lived beyond 600m. There was besides a rebuff increased hazard for those populating 200-600m from the lines at birth as this further than can readily be explained by magnetic Fieldss it may be due to other aetiological factors associated with power line.
Harmonizing to Dr. Paul Vailleneuve of the University of Ottawa finds in survey published in February 2002 that those who were exposed to a moderate 6mG of magnetic Fieldss increased by a factor of 12 their odds of developing an agressive encephalon tumour know as glioblastoma multiforme. The Nipponese National Institute for Environmental Studies and the National Cancer Center, in midterm analysis of a joint three-year study undertaking, have concluded kids who are frequently exposed to such electromagnetic moving ridges, emitted from high-potential power lines and some family contraptions, are on norm more than twice as likely to acquire leukemia than those who are non exposed to EMF.
These researches shows an indicant there are hazard involved wellness of the public peculiarly people populating nigh High Voltage Power Lines. The authorities and the govern organic structure should take these status earnestly as it involves human life and besides agonies.
Effect of magnetic field toward melatonin (Sleeping upset)
Harmonizing to Maisch, Podd and Rapley ( 2002 ) , the research has found changeless exposure of magnetic field to single will do kiping disorder.One possible manner a magnetic field could impact slumber is by impacting the production of melatonin, a endocrine produced by pineal secretory organ. The pineal secretory organ is the major control secretory organ over this rhythm, with melatonin production controlled by signals from postganglionic sympathetic fibers ( nerve cells ) connected to the hormone-producing cell of the pineal gland.The firing rate of the endocrine bring forthing varies from daytime and dark. Melatonin is known for its kiping heightening belongingss to guarantee homo would hold a dormant continuance at dark. Harmonizing to Melatonin Hypothesis: Breast Cancer and Use of Electrical Power (1997) , electromagnetic spectrum peculiarly seeable scope suppresses melatonin synthesis in the pineal secretory organ of all craniates including adult male. Dr Scott Davis of Fred Hutchinson Cancer Research Center found the higher magnetic field degrees at dark were associated with significantly lower melatonin degrees. Therefore, the researches had come to a conclusive determination that low frequence Fieldss will make dormant perturbation.
Effect on Pregnant adult females and babies
The high electromotive force power lines besides give consequence to the pregnant adult females and her babies. For an illustration a survey by Dr. De-Kun Li ( January 2002 ) shows that, a treble addition in overall self-generated abortions and a sextuple addition in self-generated abortions happening before the tenth hebdomad of gestation is associated with even fleeting exposure to magnetic Fieldss greater than 16 milligram. Similar consequences were found in a separate paper on self-generated abortions prepared for the undertaking by G. M. Lee which is printed in the same issue. Harmonizing to a intelligence study in New Scientist of January 10, 2002, Li 's consequences caused a California Health Services section scientist, Raymond Neutra, to review his 1991 survey of 727 adult females. Originally, his group 's survey had measured mean magnetic field exposures and with inconclusive consequences. However, when Neutra late reanalyzed the information from his earlier survey, he discovered the consequences were similar to Li 's. Womans exposed to top out magnetic field degrees greater than 14 milligrams doubled their hazard of abortion over those who had no such exposure.
Consequence on the Environment
High Voltage Power Lines: Power lines deliver electricity (normally at 50 or 60 Hz) and may cross 100s of kilometers. Degrees of electromagnetic Fieldss (EMF) from human-made beginnings have increased steadily over the past 50-100 old ages. Most EMF exposures come from increased usage of electricity and new engineerings. In the past decennaries, possible inauspicious effects from EMF exposure on human wellness have been an of import subject of research. However, small has been published about the impact of EMF on the natural terrestrial and aquatic environment.
The World Health Organization (WHO) is turn toing this issue through the International EMF Project. One of the Project 's aims is to supply advice to national governments and others on EMF wellness and environmental effects and protective steps or actions if needed.
This information sheet summarizes the current scientific apprehension on the effects of exposure to EMF Fieldss on the life environment, across the electromagnetic spectrum in the frequence scope 0-300 GHz. This scope covers all frequences that are emitted into the environment through usage of EMF engineering. Recommendations are besides given for farther research to make full spreads in cognition needed to better buttocks EMF environmental impacts.
Awareness of any environmental impacts of EMF is of import to guarantee the saving of tellurian and marine ecosystems, which form the footing for sustainable development. Protection of the environment and preservation of nature have become affairs of great involvement to the populace, every bit good as to authorities. Such involvement is frequently expressed as concern over possible environmental impacts of big engineering undertakings, such as dikes, atomic power works, and radiofrequency senders. Several undertakings have been capable to public force per unit areas on environmental evidences, with EMF being one but non need fully the lone issue. For illustration, a proposed high frequence (HF) wireless sender for the Voice of America in Israel, which would hold been the universe 's largest wireless station, was blocked from building on environmental evidences, in portion related to concerns about possible effects of wireless frequence Fields on migrating birds.
Public concern about environmental exposure to EMF has ranged from claims of decreased milk production in cattles croping under power lines to damage to trees nigh high power radio detection and rangings. Such concerns might besides impact the development of new engineering: several programs have been proposed since the late sixties for bring for thing electric power in infinite by revolving arrays of solar panels. Large sums of electricity generated by such solar power orbiters would be transmitted to ample aerials on the land. In add-on to get the better ofing proficient troubles, this and other new engineerings would hold to derive public credence.
Consequence on the Animals
Most surveies of EMF effects in animate beings have been conducted to look into possible inauspicious wellness effects in worlds. These are normally performed on standard research lab animate beings used in toxicological surveies, e.g. rats and mice, but some surveies have besides included other species such as like short-living flies for the probe of genotoxic effects. The topic of this information sheet, nevertheless, is whether Voltage can hold harmful impacts on species of wild and domestic animate beings. Under consideration are:
Speciess, in peculiar certain fish, reptilians, mammals and migratory birds, which rely on the natural (geomagnetic) inactive magnetic field as one of a figure of parametric quantities believed to be used for orientation and navigational cues
Farm animate beings (e.g. swine, sheep or cows) croping under power lines (50/60 Hz) or in the locality of broadcast medium aerials
Flying zoologies, such as birds and insects, this may go through through the chief beam of high power radio-frequency aerials and radio detection and ranging beams or through high strength ELF Fieldss near power lines.
Surveies performed to day of the month hold found small grounds of EMF effects on zoologies at degrees below ICNIRP 's guideline degrees. In peculiar, there were no inauspicious effects found on cows croping below power lines. However, it is known that flight public presentation of insects can be impaired in electric Fields above 1kV/m, but important effects have merely been shown for bees when electrically conductive urtications are placed straight under power lines. Un-insulated un-earthed music directors placed in an electric field can go charged and cause hurt or interrupt the activity of animate beings, birds and insects.
Harmonizing to Strauss and Bernard (1991), some of the federal Torahs in United States do non modulate electric and magnetic Fieldss due to public deductions and besides multi billion dollar electricity industries in the States. Some of the new Torahs are non based on scientific dictum about safe degree of magnetic filed exposure but instead on the premise that the position quo is publically acceptable.
With this statement, In Malaysian 's the ordinances and act on the High Voltage Power Lines are non truly specific and all conditions could be change by the Minister in charge.
As refer to all the risky possibilities, yet still there are non proved status the danger of the magnetic moving ridge towards human wellness. There are a few researches shown there is a really high possibility of developing malignant neoplastic disease due high electromotive force transmittals lines but none of the research is definite and conclusive. Besides malignant neoplastic disease, a research has found low frequence magnetic moving ridge could strip homo 's sleeping form during dark clip because of stamp downing the melatonin endocrine. Other than that, the status or location of the transmittal line in Malaysia has lid concerns when the transmittal lines fluxing through the paddy field, the wood and besides the lodging estate.
As for the ordinance concerns, due to none of the researches shown the danger of magnetic moving ridge in malignant neoplastic disease and other risky status, safeguards of these safety conditions are neglected. Equally long as there is no complain or human death from the populace, the authorities assume it has reach the safety demands. Therefore, we as the citizens or public, have to go a victim foremost before any Act or Regulation would be drafted to avoid such state of affairs. Make bear in head, it is non prevention but simply an turning away from the authorization.
As more underdeveloped states are traveling frontward towards industrialization, more power lines are needed and more power works will be build to for coevals. Therefore is our female parent Earth in the save from these magnetic moving ridges? Will it destruct our Earth and human sort or the mutational conditions has reached its extremum? No organic structure can reply it. As what a politician would state, there is non danger unless there are marks of decease or irreversible conditions. Uncertainty is the most deathly status compared to certainty.