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International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) Investigation and Analysis of Electromagnetic Radiation on High Voltage Transmission Line S. Priya 1, Dr. P. Anbalagan 2 1 PG Scholar, 2Assistant Professor, Department. of EEE, AUT-BIT Campus, Trichy Abstract— High voltage power lines produce electromagnetic radiation; this electromagnetic radiation can cause various health hazards to humans. Several developments have taken place in the design of the power lines such as increasing the distance between Neighboring transmission lines and the residences decreasing the current, shielding, changing the geometry of the conductors through the compaction method, the phase splitting method as well as the current-phase rearrangement method, to reduce the radiation. It is important to implement these techniques because many researchers still suspect the existence of an association between the EMF induced from power lines and health damages despite all the studies which failed to prove the presence of a causal relationship. The main objective of this work is to give a detailed analysis of the magnetic fields emitted by 220 kV power transmission lines. The work starts by an overview on the latest developments in the power line designs, including recent configurations and the different ways of conductor placements that help in reducing the emitted magnetic fields and by a review of the basic magnetic field equations that will be used later in the comparison of theoretical and actual values. This work is implemented by using MATLAB. ELF-EMFs have frequencies of up to 300 cycles per second, or Hertz (Hz); for example, the frequency of alternating current in power lines is 50 or 60 Hz. Cell phones produce radiofrequency EMFs above the ELF range. For more information about cell phones, see the NCI Fact Sheet Cell Phones and Cancer Risk. Electric fields are easily shielded or weakened by walls and other objects, whereas magnetic fields can pass through buildings, living things, and most other materials. Consequently, magnetic fields are the component of ELF-EMFs that are usually studied in relation to their possible health effects. Electric and magnetic fields (EMFs) are invisible areas of energy, often referred to as radiation, that are associated with the use of electrical power and various forms of natural and man-made lighting. EMFs are typically characterized by wavelength or frequency into one of two radioactive categories: Non-ionizing: low-level radiation which is generally perceived as harmless to humans Ionizing: high-level radiation which has the potential I. INTRODUCTION Electric and magnetic fields are invisible areas of energy that are produced by electricity, which is the movement of electrons, or current, through a wire. An electric field is produced by voltage, which is the pressure used to push the electrons through the wire, much like water being pushed through a pipe. As the voltage increases, the electric field increases in strength. A magnetic field results from the flow of current through wires or electrical devices and increases in strength as the current increases. The strength of a magnetic field decreases rapidly with increased distance from its source. Electric and magnetic fields together are referred to as electromagnetic fields, or EMFs. There are both natural and human-made sources of EMFs. The earth’s magnetic field, which causes a compass to point North, is an example of a naturally occurring EMF. Power lines, wiring, and electrical appliances, such as electric shavers, hair dryers, computers, televisions, and electric blankets produce what are called extremely low frequency (ELF) EMFs. E-ISSN :2348 - 8379 for cellular and DNA damage Fig. 1 Radiation Spectrum EMF is Harmful to Health: During the 1990s, most EMF research focused on extremely low frequency exposures stemming from conventional power sources, such as power lines, electrical substations, or home appliances. While some of these www.internationaljournalssrg.org Page 62 International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) studies showed a possible link between EMF field strength and an increased risk for childhood leukemia, their findings indicated that such an association was weak. Now, in the age of cellular telephones, wireless routers, and portable GPS devices (all known sources of EMF radiation), concerns regarding a possible connection between EMFs and adverse health effects still persists, though current research continues to point to the same weak association. Additionally, the few studies that have been conducted on adults show no evidence of a link between EMF exposure and adult cancers, such as leukemia, brain cancer, and breast cancer. Nevertheless, NIEHS recommends continued education on practical ways of reducing exposures to EMFs. II. RELATED WORKS H. Ahmadi et al (2010), has discussed about the problems and solutions for the electromagnetic fields near transmission line. The people are highly concerned about the effects of high voltage transmission lines on their health. Probable risk for leukemia, breast cancer, neuropsychological disorders and reproductive outcomes has been reported due to this exposure. In this study, several measurements around different areas such as overhead transmission lines, GIS compartments and some appliances have been conducted and compared with the standard tolerances. The emphasis of this research is on high voltage substations and publics. Field magnitudes above 10kV/m have been measured under wires. Results show that there is no serious concern for the people living near the transmission lines but for the individuals who are beneath those lines for long. Recent achievements about electric fields’ effect on human health are reviewed.[1] Girish Kulkarni et al(2012), has suggested about the proximity effects of high voltage transmission lines on humans. New threats to humans are observed from electromagnetic radiation from various sources like mobile phones, transmission lines and many more. For providing continuous and uninterrupted supply of electric power to consumer’s maintenance operation of high voltage power lines are often performed with systems energized or live. This is referred as Hot Line maintenance or live line maintenance in this paper authors are concentrating on effects due to high voltage transmission lines on persons involved in this live line maintenance. The main aim of this paper is to create a model for health hazards in high voltage transmission lines. In this paper just a theoretical approach is presented, in coming days the model suggested will be prepared with ANSYS or MATLAB [3]. Djalel et al (2014) has presented the study of the influence high-voltage power lines on environment and human health. The methodology for calculating the electromagnetic field radiated by the high voltage (HV) lines and for selection of analytical models that interpret the electric and magnetic fields as a function of the distance to the target object. The results were compared with measurements carried out on site where the HV lines are E-ISSN :2348 - 8379 present through a neighborhood of a large agglomeration in the city of Tebessa, for over 50 years. Following published standards establishing the human to HV power line distances for professional exposure or in the case of low frequency field exposure the results obtained by calculations /simulation and measurement in this work, enable us to recommend possible solutions for the electromagnetic pollution issues in the town of Tebessa and thus to reduce the permanent danger to the public considering also the legislative vacuum and the poor preoccupation of official authorities [8]. IV. INVESTIGATION OF EMF IN POWER TRANSMISSION LINE Recognizing that there is a great deal of public interest and concern regarding potential health effects from exposure to electric and magnetic fields (EMFs) from power lines, this section provides information regarding EMF associated with electric utility facilities and the potential effects of the proposed Project related to public health and safety. Potential health effects from exposure to electric fields from power lines is typically not of concern since electric fields are effectively shielded by materials such as trees, walls, etc.; therefore, the majority of the following information related to EMF focuses primarily on exposure to magnetic fields from power lines. ELECTROMAGNETIC RADIATION Electromagnetic radiation (EM radiation or EMR) is the radiant energy released by certain electromagnetic processes. Visible light is one type of electromagnetic radiation; other familiar forms are invisible electromagnetic radiations, such as radio waves, infrared light and X rays. Classically, electromagnetic radiation consists of electromagnetic waves, which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light through a vacuum. The oscillations of the two fields are perpendicular to each other and perpendicular to the direction of energy and wave propagation, forming a transverse wave. Electromagnetic waves can be characterized by either the frequency or wavelength of their oscillations to form the electromagnetic spectrum, which includes, in order of increasing frequency and decreasing wavelength: radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, Xrays and gamma rays. PROTECTION FROM POWER LINE RADIATION Your best protection from power line health risks is knowledge, and that may mean taking measurements. If you have no way of measuring power line radiation levels, it may help to know that the strongest high voltage transmission lines (220kV) typically produce less than 0.5 mill gauss EMF at 200 meters. The strongest street pole power lines (33 kV) generally produce less than 0.5 milligauss at 25 metres. Many street pole power lines are of www.internationaljournalssrg.org Page 63 International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) a lower voltage than this, and their EMF would extend far less. Power lines vary, so if your house is less than 200 meters from major power lines, or within 25 meters of street-pole power lines, you may want to use a Low Frequency Gauss meter suitable for power line radiation detection [4]. Now we must analyze the transmission tower characteristics that were given and calculate relative positioning of all the conductors: C. PROPOSED SYSTEM The problem basically gave me the parameters of a specific transmission line and asked for the electromagnetic values at a constant height of 1.8 meters from ground (approximately the height of a person's head), considering that the person could move on the X axis of a transverse section of the power line. The electromagnetic field, as the name says, is made of 2 components, the electric field and the magnetic field. This work will analyze them separately in different time instants, both in normal conditions and hypothetical abnormal or accidental situations The transmission line being analyzed is a 3-phased, 50 Hz alternating current power line considering a voltage of 400kV and a power of 1200MVA. Each phase is composed of 2 conductors ("bundled" 2 ways) each one having a diameter of 31.8 mm. There are also 2 overhead earth wires or shield wires on the top of the tower, each one having a diameter of 23.45 mm. All the important distances are represented on the previous image (in meters). The section being studied is an area perpendicular to the length of the conductors, considering 40 m for each side from the center of the tower (on the X axis) and a height of 50 m from the ground (on the Y axis). First some physics. For the magnetic field we have Ampere’s Law, which is an electromagnetism law that relates the magnetic field in a closed loop or surface with the electric current circulating through that same loop: ∮ ⃗. d⃗ = .i → 1 To determine the electromagnetic field of this transmission line, we're also gonna need to use the method of images, also known as method of mirror charges. This method is used as a mathematical tool to solve electromagnetic problems by adding a mirror image of the conductor, with the opposite charge, in relation to a common surface, in our case, the ground. To apply this, we just replicate the conductors underneath the soil, like the ground was a mirror, and consider the current on them to be the same but with opposite direction. The cross inside the conductors represents the back side of a vector and the point represents the front side, establishing the sense of direction. Fig. 4 Transmission Tower Characteristics Considering the center of the image as the center of the referential for X and Y. We can now take the coordinates of all the conductors. I'm also representing them as imaginary numbers to make mathematical calculations easier. These are the coordinates for the real and imaginary conductors: P1a = -d3 + hj P1ai = -d3 - hj P1b = -d2 + hj P1bi = -d2 - hj P2a = -d1 + hj P2ai = -d1 - hj P2b = d1 + hj P2bi = d1 - hj P3a = d2 + hj P3ai = d2 - hj P3b = d3 + hj P3bi = d3 – hj Pg1 = -d4 + hgj Pg1i = -d4 - hgj Pg2 = d4 + hgj Pg2i = d4 - hgj → 2 We need the distances between live conductors to be able to calculate the matrix of the coefficients of potential. TRANSMISSION TOWER CHARACTERISTICS E-ISSN :2348 - 8379 www.internationaljournalssrg.org Page 64 International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) Fig.4 Image Conductors Fig. 5 Input Coordinates to Coefficients Vertical and horizontal distances are directly obtained by analyzing the previous image but the diagonal distances need to be calculated. Having established all the coordinates is now easier to get them. To get the diagonal distance you can just calculate the modulus or absolute value of the difference between 2 points. The distances are: LINE VOLTAGE Now we know that the line to line voltage is 400kV, so the instantaneous line to neutral voltage is given by: We are also gonna need the distances between live conductors and the shield wires: V1(t) = √ . H1 = |P1a – P1bi| = 60.0013 m V2(t) = √ . H2 = |P1a – P2ai| = 60.6132 m V3(t) = √ . H3 = |P1a – P2bi| = 60.6712 m √ √ √ × 103. ej(ω.t) × 103. ej(ω.t - 2π/3) × 103. ej(ω.t + 2π/3) → 4 H4 = |P1a – P3ai| = 62.4167 m H5 = |P1a – P3bi| = 62.5281 m H6 = |P1a – P2bi| = 60.5577 m → 3 H7 = |P1a – P1bi| = 62.3076 m Where omega is the angular speed for a frequency of 50Hz. Each phase is composed of 2 conductors; therefore the voltage in each conductor is approximately the same. Also the shield wires are considered to have 0V. We know this line has a power of 1200MVA, so we can calculate the current: In = √ . = × √ . × = 1732.1 A →5 For this particular scenario we are considering a power factor of 1, even though this is obviously not what happens in reality. Although this is not a real situation, this consideration shall not change the values of the electric and magnetic fields, but just change the time instant when they occur. What this means is that the values of the final results are still correct, but their timings might not be the ones indicated. 1. Line Current Fig. 4 Distance of Conductors and Shield wires These are the instantaneous current values for each phase: I1(t) = √2. In . ej(ω.t) I2(t) = √2. In. ej(ω.t - 2π/3) I3(t) = √2. In . ej(ω.t + 2π/3) → 6 Since there are 2 conductors in parallel for each phase, we can consider the current on each conductor to be aproximmately half of the phase current. Then we can also assume that the current on the shield wires is 0A, since their voltage is also 0V. E-ISSN :2348 - 8379 www.internationaljournalssrg.org Page 65 International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) . = . ∙ , < , > 2 ⎡ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎡ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎤ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ →7 With all these considerations done, we can finally start calculating the magnetic field. We have reached the equation for the magnetic induction Now we must attend to some factors: We have seen that the direction of the current on the phase conductors is the opposite of the direction in the "image" or mirrored conductors. This must be represented in the equation with a mathematical operator, and since the coordinates are complex numbers, that operator can be just 'j' (I'm using 'j' as the imaginary unit instead of 'i' to avoid confusions with the currents). Other factor we must pay attention happens when 'r' is larger than the radius 'R', because 'r' is the distance between the point you are analyzing and the conductor, which is given by a complex number, and the fact that is being used on the denominator of the equation means that the direction of the vector is gonna change and it'll give you a wrong result. To correct this, in that situation we are going to use the conjugate of 'r'. \ ⎤ ⎥ ⎥ ⎥ . ⎥ ⎥ ⎥ ⎦ →9 Going back to the electric field equation, we now have the electric charges values, so we can adapt to: ̇n = . Im ( ̇ . ). ( | ̇ ̇ | - | ̇ ̇ | ) → 10 By varying X and Y we'll get the values for a specific area: E(y, x) = Ep → 11 The matrix [A] can now be filled: ⎡ ⎢ ⎢ [ ]=⎢ ⎢ ⎢ ⎢ ⎣ ⎤ ⎥ ⎥ ⎥ ⎥ ⎥ ⎥ ⎦ And finally, the charges can be obtained by: ⎡ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎢ ⎣ ⎤ ⎥ ⎥ ⎥ ⎥= ⎥ ⎥ ⎥ ⎦ →8 V. IMPLEMENTATION OF PROPOSED SYSTEM The frequency (f) is 50Hz and the period (T) is 20ms, I decided to analyze 6 time instants, from 0ms to 8.333ms, each with an interval of T/12 ms. I'm analyzing just 6 because after those, the values will start repeating, even though the voltage and current will have opposite values, in absolute values, they will be the same. To have some kind of reference here are some common EMF values for domestic appliances: Refrigerator Stereo TV Toaster - 0,3µT and 90V/m; - 1µT and 90V/m; - 2µT and 60V/m; - 0,8µT and 40V/m; From this instant on, the graphs will start repeating themselves, passing through the same situations. E-ISSN :2348 - 8379 www.internationaljournalssrg.org Page 66 International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) By analyzing the figures, it is curious to observe that sometimes, the center of the tower, at ground level, has lower EMF values than the sides of the tower, a fact that is commonly unknown by most, which proves that is safer to be right beneath than to be just next to it. Fig. 5.2 Electric Field Test System 230KV: Sn Un Vg F Length Height T H Hg D D1 D2 D3 D4 = = = = = = = = = = = = = = 1000e6 400e3 0; 50; 40; 50; 0.02/3 30; 35; 0.4; 0.2; 8.4; 8.8; 4.3; % Current % Voltage % Initial voltage % Frequency % Width and Height % the area to analyze % time instant to analyze Comparision of MATLAB code Table- I Output Spectrum of EMF Magnetic Field 50 Ii = 1.00E+08 A Vi = 400000 V T= 0.0067 MA diameter 0.0318 diameter2 0.0234 In 1.44E+03 Phase i1 = -1.0206e+03 + 1.7678e+03i Phase i2 = 2.0412e+03 + 9.0649e-13i Phase i3 = -1.0206e+03 - 1.7678e+03i Phase v1 = -1.6330e+05 + 2.8284e+05i Phase v2 = 3.2660e+05 + 1.4504e-10i Phase v3 = -1.6330e+05 - 2.8284e+05i 45 40 VI. CONCLUSION 35 Y-axis(m) 30 25 20 15 10 5 0 -40 -30 -20 -10 0 X-axis(m) 10 20 30 40 Fig. 5.1 Magnetic Field Electric Field 50 45 Although the science is far from conclusive, a substantial base of data exists from years of research which is highly suggestive of an association between exposure to electromagnetic fields and the development of certain health problems. Identification of these groups aggressed of people would be impractical given our current state of knowledge, but their risk would be greater than the general population. The HV power lines are a source of pollution to the 40 35 Y-axis(m) 30 25 20 15 10 5 E-ISSN :2348 - 8379 0 -40 The power transmission line is one of the major components of an electric power system. Its major function is to transport electric energy, with minimal losses, from the power sources to the load centers, usually separated by long distances. For the electric field, simulation, the results of modeling and measurements coincide and give satisfaction. The difference found between theory and measurement at a distance of 35-40 m where the B field rebounds (fluctuation), could be generated by external parameters such as electric permittivity ε and magnetic permeability µ of the soil varying from one location to another, also by climatic and atmospheric conditions such as humidity and environmental temperature gradients. -30 -20 www.internationaljournalssrg.org -10 0 X-axis(m) 10 20 30 40 Page 67 International Conference on Current Research in Engineering Science and Technology (ICCREST-2016) environment through its direct assault on the landscape, land use in the city or agricultural land and its impact on human and animal health by its electromagnetic radiation REFERENCE [1] H. Ahmadi, S. Mohseni, A. A. ShayeganiAkmal, Electromagnetic Fields near Transmission Lines – Problems and Solutions, Iran J. Environ. Health. Sci. Eng., 2010, Vol. 7, No. 2 pp. 181-188. [2] G. Draper , T. Vincent, M.E. Kroll , J. Swanson. Childhood cancer in relation to distance from high voltage power lines in England and Wales: a casecontrol study. CCRG, University of Oxford, British Medical Journal BMJ 04 June 2005. [3] GirishKulkarni, Dr.W.Z.Gandhare, Proximity Effects of High Voltage Transmission Lines on Humans, ACEEE Int. J. on Electrical and Power Engineering, Vol. 03, No. 01, Feb 2012 [4] M. H. Shwehdi and U. M. Johar, Transmission Line EMF Interference with Buried Pipeline: Essential & Cautions, Proceedings of the International Conference on Non-Ionizing Radiation, pp2, 2003. [5] Ahlbom A, Day N, Feychting M, Roman E, Skinner J, Dockerty J. A pooled analysis of magnetic fields and childhood leukemia. Br J Cancer, 2000,83:692-698. [6] Nitsch J, Gronwald F, Wollenberg G. Radiation non uniform transmission line and the partial element equivalent circuit method. 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Cancer Causes Control; 1998. 9 : 299309. [12] R Matthes, A McKinlay, J Bernhardt Eds. Exposure to static and low frequency electromagnetic fields, biological effects and health consequences (0-100 kHz). ICNIRP.2004. [13] Ivancsits S, Diem E, Pilger A, Rudiger HW, Jahn O. Induction of DNA strand breaks by intermittent exposure to extremely-low-frequency electromagnetic fields in human diploid fibroblasts. 2002. 519 :1-13. E-ISSN :2348 - 8379 [14] Ivancsits S, Diem E, Jahn O, Rudiger HW. Age-related effects on induction of DNA strand breaks by intermittent exposure to electromagnetic fields. Mech Ageing Dev 2003.124:847-50. [15] Ivancsits S, Diem E, Jahn O, Rudiger HW. Intermittent extremely low frequency electromagnetic fields cause DNA damage in a dose-dependent way. Int Arch Occup Environ Health, 2003. 76:431-436. www.internationaljournalssrg.org Page 68