High Power Transmission Lines Research Articles

Design of a TE01-Mode Waveguide Bend Based on an Elliptical Waveguide Structure

A Ka-band broadband TE01-mode overmoded waveguide bend based on an elliptical waveguide structure is proposed for high-power transmission line in this paper. To investigate the mode conversion inside the waveguide bend, the mode coupling coefficients of elliptical waveguide bend are theoretically deduced. The influence of the cross section on the power-handling capacity and the transmission efficiency is studied. Calculation and simulation results present that the proposed overmoded waveguide bend has a propagation bandwidth of 7 GHz (relative bandwidth of 21%) with an efficiency over 95%. A prototype is fabricated and measured. The average transmission efficiency is over 93% in the range of 29–36 GHz according to the S-parameter measurement. The results of near-field test demonstrated that a TE01 mode with high purity is obtained at the output port of waveguide bend. The high-power performance is investigated by connecting it with a Gyrotron traveling wave tube, and the waveguide bend works stable under a maximum output power of 150 kW. The measurement results demonstrate that a novel approach is proposed successfully for the design of high-power waveguide bend.

Shielding failure analysis of a hybrid transmission line with AC and DC systems on the same tower

Hybrid AC/DC transmission lines have different systems on the same tower and combine HVDC transmission over long distances with common HVAC transmission. Evaluation of the risk of lightning stroke outage of high power transmission lines is very important because lightning strokes cause mainly outages. The present paper illustrates how to combine efficiently different methods to support insulation coordination studies. Maximum lightning current amplitude that does not cause flashover across insulator string is estimated in response to first and subsequent lightning strokes with three different flashover models using several electrogeometric models and simulations in EMTP-ATP. Characteristic quantities like Shielding Failure Rate (SFR) and Shielding Failure Flashover Rate (SFFOR) are calculated for different shielding configurations.

Analyzing the Health Risks Resulting from Extending the 400kV High Voltage Transmission Lines on the Human

Although it is difficult to imagine life without electricity, there are compiling confirmations show thatexposure to magnetic fields correlated electricity and radio frequencies pose magnificent hazards to human health. The most economist method to transfer electricity from power generation stations to users is by measures of high power transmission lines, buoyed by big transmission towers. The cables laced between the towers radiate magnetic and electric fields. In this research study, the magnetic field at ground level under 400 kV network lines extended in residential places have been conducted in two ways, mathematical calculation and practical measurement then the obtained results analyzed and compared with the international standards reference values. the reason of chose this type of transmission line is frequently using. The results indicate that they fall within the safe limiter commended by the WorldHealth Organization. the strength of radiation increasing with high of sea level and moisture ratiobecause of air ionization.

Research on Safety Protection for Live Working on 1000kV AC Transmission Line with AC and DC Multi-circuit Transmission Lines

In recent years, in order to save line corridors and reduce the scope of demolition, some new transmission modes for high voltage AC and DC power transmission line are proposed. According to the characteristics of the parallel transmission line, this paper studies the distribution characteristics of the electric field intensity of multi circuit parallel transmission lines and the single circuit transmission line. Comparing and analysing the simulation results of the electric field strength, the safety measures for live working of 1000kV AC transmission line with multi circuit parallel transmission lines is put forward. That is the electric field protective equipment and measures used in the live line work of the 1000kV UHV AC single circuit line can meet the requirements of the live operation of the 1000kV UHV AC double circuit line.

Design of high power RF amplifier for 3 MW/CW transmission line test rig

India is developing 2.5MW RF source at VSWR 2:1 in the frequency range 35–65MHz for ITER project. Eight such RF sources will generate total 20MW of RF power for plasma heating and current drive. A large number of high power transmission line components are required for connecting various stages of RF source. To test these passive transmission line components at high power, a 3MW test facility based on the concept of Traveling Wave Resonator (TWR) is underway. A high power CW RF amplifier is required to feed RF power to 10dB coupler of TWR. To fulfill the requirement a tetrode based amplifier is designed to operate in class B with optimized efficiency, gain and harmonics level. The detail design is carried out to estimate operational parameters derived from the data sheet of selected tetrode, simulation for RF cavities, power supply requirements and thermal management for CW operation.

Research on safety protection for live working on ±800kV DC transmission line with AC and DC multi-circuit transmission lines

In recent years, in order to save line corridors and reduce the scope of demolition, some new transmission modes for high voltage AC and DC power transmission line are proposed. According to the characteristics of the parallel transmission line, this paper studies the distribution characteristics of the electric field intensity of multi circuit parallel transmission lines and the single circuit transmission line. Comparing and analysing the simulation results of the electric field strength, the safety measures for live working of ±800kV DC transmission line with multi circuit parallel transmission lines is put forward. That is the electric field protective equipment and measures used in the live line work of the ±800kV UHDC single circuit line can meet the requirements of the live operation of the ±800kV UHDC multi-circuit transmission line.

Analyzing the Health Risks Resulting from Extending the 400kV High Voltage Transmission Lines on the Human

Although it is difficult to imagine life without electricity, there are compiling confirmations show that exposure to magnetic fields correlated electricity and radio frequencies pose magnificent hazards to human health. The most economist method to transfer electricity from power generation stations to users is by measures of high power transmission lines, buoyed by big transmission towers. The cables laced between the towers radiate magnetic and electric fields. In this research study, the magnetic field at ground level under 400 kV network lines extended in residential places have been conducted in two ways, mathematical calculation and practical measurement then the obtained results analyzed and compared with the international standards reference values. the reason of chose this type of transmission line is frequently using. The results indicate that they fall within the safe limiter commended by the World Health Organization. the strength of radiation increasing with high of sea level and moisture ratio because of air ionization

A Millimeter Wave High-Order TE13 Mode Converter

In this paper a methodology to excite a circular high-order TE13-mode via a rectangular TE50 mode was proposed and verified by the millimeter wave measurement. This topology can also be applied to launch other high-order modes (HOMs) such as TE $_{1n}$ , TE $_{2n^\prime }$ and TE $_{0n^\prime }$ (n or $n^\prime =1$ , 2, 3) modes via different transition rectangular TE $_{m0}$ ( $m = 2n-1$ or $m = 2n^\prime $ ) modes, which can be achieved by adjusting the number of coupling apertures and optimizing dimensions of tapered waveguides. A W-band TE13 mode converter was designed and analyzed. Two identical converters connected back to back as a proof-of-principle operating at $Q$ -band were fabricated and measured. Good performance was observed, which was in good agreement with the simulation results. This HOM converter has many potential applications in areas such as gyro-devices, high-power transmission lines, RF multimode systems of accelerators, microwave/plasma, and antenna systems.

Quantitative Analysis of Plant Growth Exposed to Electric Fields

Electromagnetic radiations present in the environment has a profound effect on the growth of vegetable plant primarily grown under the high power transmission lines. The high electric field generated due to ultra high voltage causes the increase and reduction in the size of the plants. Numerous research have been carried out to investigate the effect of electric field on the plants. However, the knowledge in term of quantitative analysis on the effect of electric field on the growth of vegetables is not entirely understood. Thus, this paper presents a study conducted to investigate the effect of high voltage DC electric fields on the young vegetables growth namely ‘Choy Sam’ and bean sprout. The experimental setup was designed which composed of two parallel plate electrodes. This research was focused on the percentage of germination and growing rate of young vegetables . The growth of the young vegetables during exposure was calculated by using statistical methods. The analysis of the results showed that the electric fields and the electric fields treated water have influenced the germination rate and height of stems of both young vegetables causing the increase in stem height.

Quantitative analysis of plant growth exposed to electric fields

Electromagnetic radiations present in the environment has a profound effect on the growth of vegetable plant primarily grown under the high power transmission lines. The high electric field generated due to ultra high voltage causes the increase and reduction in the size of the plants. Numerous research have been carried out to investigate the effect of electric field on the plants. However, the knowledge in term of quantitative analysis on the effect of electric field on the growth of vegetables is not entirely understood. Thus, this paper presents a study conducted to investigate the effect of high voltage DC electric fields on the young vegetables growth namely ‘Choy Sam’ and bean sprout. The experimental setup was designed which composed of two parallel plate electrodes. This research was focused on the percentage of germination and growing rate of young vegetables. The growth of the young vegetables during exposure was calculated by using statistical methods. The analysis of the results showed that the electric fields and the electric fields treated water have influenced the germination rate and height of stems of both young vegetables causing the increase in stem height.

Measurement of Magnetic Field from Electrical Appliances in EEE Classrooms of Southeast University Bangladesh

The aim of this survey is to investigate whether the Electromagnetic Fields (EMF) emitted from various air conditioners and switch boards affect the students, faculties and employees. There is a standard threshold value recommended by World Health Organization (WHO) for both electric and magnetic fields. Electro-Magnetic Fields commonly known as Non Ionizing Radiation is emitted from high power transmission lines, computer monitor/video display unit, radio waves of different frequencies (extremely low frequency to microwaves), telecommunication, satellite, radar etc. which causes health hazards to living system and environment. There has not been much study performed in Bangladesh. The data were collected from various Electrical and Electronic department classrooms at Southeast University in Dhaka, Bangladesh. Both threshold values of Electric and Magnetic fields were measured for various air conditioners and switchboards. The maximum value of the magnetic field results showed that in many cases the magnetic field radiated from the different sources are greater than the threshold limit, which are the main point of our findings.

High-Power Ka-Band Transmission Line with a Frequency Bandwidth of 1 GHZ

We present experimental results on a high-power transmission line from the broadband pulsed Ka-band gyro-TWT to the phased antenna array. The transmission line is designed to operate in a pulse-periodic regime with a pulse width of up to 250 μs, a duty factor of 8, and an average output power of up to 15 kW. Amplitude–frequency and phase–frequency characteristics of the transmission line were measured at a low power level. It is shown that the nonlinearity of the phase–frequency characteristic does not exceed ±10° in the 34 ± 0.5 GHz frequency band.

A Review on Level of Specific Absorption Rate Due to High Power Transmission Lines: Analysis toward Human Position Posture

The main contribution of this project is the development of a homogeneous model of a man to presents the specific absorption rate (SAR) due to high power transmission line. As a low frequency application under high power transmission line of 50 Hz in electrical engineering, to studies the influence of human’s posture on specific absorption rate. This project designs two types of human body which one design uses most cylinder block and another design use brick block where both blocks have a different value of mesh cells. For each design has four types of posture are standing, sitting, arms up and arms out by using Computer Simulation Technology (CST) Studio Software. This analysis does toward for four types of the human position postures because each posture has different value of specific absorption rate (SAR) based on the size of the mesh cells of the design. Based on two designs of the human body, the lowest of the mesh cells value will reduce time to simulate SAR. For each posture has different value of SAR for each part of the human body because the whole human body has different types of tissues. Therefore, the CST studio software uses extremely to simulate the SAR value toward human position posture due to high power transmission line.

Quantitative Analysis of Plant Growth Exposed to Electric Fields

<p>Electromagnetic radiations present in the environment has a profound effect on the growth of vegetable plant primarily grown under the high power transmission lines. The high electric field generated due to ultra high voltage causes the increase and reduction in the size of the plants. Numerous research have been carried out to investigate the effect of electric field on the plants. However, the knowledge in term of quantitative analysis on the effect of electric field on the growth of vegetables is not entirely understood. Thus, this paper presents a study conducted to investigate the effect of high voltage DC electric fields on the young vegetables growth namely ‘Choy Sam’ and bean sprout. The experimental setup was designed which composed of two parallel plate electrodes. This research was focused on the percentage of germination and growing rate of young vegetables. The growth of the young vegetables during exposure was calculated by using statistical methods. The analysis of the results showed that the electric fields and the electric fields treated water have influenced the germination rate and height of stems of both young vegetables causing the increase in stem height.</p><p> </p>

SURVEY OF EMF EMITTED BY LAB EQUIPMENTS IN PHARMACY LABS OF SOUTHEAST UNIVERSITY IN BANGLADESH

The aim of this survey is to investigate whether the Electromagnetic Fields (EMF) emitted by various lab equipments affects t he students. There is a standard threshold value recommended by WHO for both electric and magnetic fields. Electro -Magnetic Fields commonly known as Non Ionizing Radiation is emitted from high power transmission lines, computer monitor/video display unit, radio waves of different frequencies (extremely low frequency to microwaves), telecommunication, satellite, radar etc. which causes health hazards to living system and environment. The WHO/ International Agency for Research in Cancer (IARC) has classified radio frequency electromagnetic field as possibly carcinogenic to humans. There has been no such study performed in Bangladesh. The data were collected from various labs of department of pharmacy at Southeast University in Dhaka, Bangladesh. These labs are Pharmaceutical, Cosmetology and Biopharmaceutical Lab, Pharmacology Lab, Organic Pharmacy and Pharmacognosy Lab, Inorganic Pharmacy Lab and Microbiology Research Lab . Both threshold values of Electric and Magnetic fields were measured for various electronic equipments. Also the maximum value of the magnetic field results showed that in many cases the magnetic field radiated from the different sources are greater than the threshold limit which are the main point of our findings. As a result of the long time efforts of world scientist community WHO formed ICNIRP in 1969.

Survey on Effect of EMF Emitted by CRT Computer Monitors in Bangladesh

As the world is being industrialized and technological revolution continues, there has been an unprecedented increase in the number and diversity of electromagnetic sources. While all these devices have made our lives richer, comfortable and easier, they have been accompanied by concerned possible health risks due to their electromagnetic field (EMF) emission. Electro-Magnetic Fields commonly known as Non Ionizing Radiation is emitted from high power transmission lines, computer monitor/video display unit, radio waves of different frequencies (extremely low frequency to microwaves), telecommunication, satellite, radar etc. which causes health hazards to living system and environment. CRT monitors are still being used in various computer composing shops, photocopy machine shops. Their EMF health effects have not been studied in Bangladesh. The data were collected from various places in Dhaka, Bangladesh: Banani Super Market, Mohakhali, Farmgate Green Road, Nilkhet and Uttara. Both Electric and Magnetic fields were measured for CRT monitors. These results showed that in many cases the magnetic field radiated from the different sources are greater than the threshold limit.

Design of polarizers for a mega-watt long-pulse millimeter-wave transmission line on the large helical device.

The polarizer is one of the critical components in a high-power millimeter-wave transmission line. It requires full and highly efficient coverage of any polarization states, high-power tolerance, and low-loss feature. Polarizers with rounded shape at the edge of the periodic groove surface are designed and fabricated by the machining process for a mega-watt long-pulse millimeter-wave transmission line of the electron cyclotron resonance heating system in the large helical device. The groove shape of λ/8- and λ/4-type polarizers for an 82.7 GHz transmission line is optimally designed in an integral method developed in the vector theories of diffraction gratings so that the efficiency to realize any polarization state can be maximized. The dependence of the polarization states on the combination of the two polarizer rotation angles (Φλ/8, Φλ/4) is examined experimentally in a low-power test with the newly developed polarization monitor. The results show that the measured polarization characteristics are in good agreement with the calculated ones.

Methods of detection of power transmission lines components using image analysis

Introduction of modern, automatic methods of technical diagnostics is very important nowadays. Among numerous technical objects of high importance power transmission lines are required to be diagnosed regularly. Considering the difficulties in performing their inspection due to their extensive length and large dimensions of particular elements, there is a need of developing and aiding currently used diagnostic techniques. A group of the methods of diagnostics of such lines is based on the vision inspection both with use of regular television (TV) and also infrared cameras. The authors of the paper focused on applying methods of image processing and analysis in order to detect components of power lines in images gathered during vision inspections. An approach to defects detection on the basis of images obtained by a regular TV and infrared camera was presented. The results of the research indicated that special approaches are needed to be performed, mainly because of a very composed and variable background in the images.

High-Power Transmission Line Transformer Design for Plasma Generators

Efficient and novel design method to implement high-power transmission line transformers (TLTs) that can be used as output balun for plasma generators is presented. The novelty in the presented method involves: the construction of the balun using transmission lines (TLs) in the form of microstrip configuration, which gives higher power handling capacity with larger amount of current and high breakdown voltage, accurate formulation including magnetic design of the balun, such as core selection, flux density, operational current, voltage, and number of turns, and implementation of the balun for radio frequency amplifier section of the plasma generator for the first time. The presented method also integrates Dowell's formulation into microstrip type design and shows that when TLs with rectangular cross sections, such as copper strips, are used for winding, thermal profile of the balun improves since its conductor loss is reduced. Design charts based on analytical formulation to design high-power TLTs are presented. High-power TLT is then constructed, measured, and implemented for 2-MHz plasma generator. All the measurement results, including thermal profile of the TLT and power amplifier performance of the plasma generator at the center frequency, 2 MHz, when the new type of TLT is implemented have been given. It has been shown that the TLT using the design technique presented in this paper can be used as output balun for plasma generators and meet all the requirements of plasma applications.

Artificial Neural Network Assisted Digital Image Processing to Determine the Hydrophobicity of Polymeric Materials

Hydrophobicity of polymeric insulators of high power transmission line is an important property because it is a good monitor of aging of polymeric outdoor insulator. An employee on the high-voltage transmission line makes this procedure during operation, which can lead to injuries and incorrect estimation of the insulator integrity. In this way, digital image processing is a promising and objective tool to analyze the polymer surface. In this study, two thousand pictures were taken from the wetted insulator surface and analyzed by artificial neural network assisted digital image processing. The neural network used is based on back-propagation method, and Haralicks descriptors were used to quantify the hydrophobic aspect of various polymeric aged surfaces.