kV High Voltage Power Research Articles

SIMPLE ELECTROSPINNING ASSEMBLY FOR THE PREPARATION OF POLYVINYL ALCOHOL NANOFIBERS CONTAINING PIPER BETLE (L)

Objective: The aim of this research was to assemble an electrospinning device with some components from used medical devices in hospital, so that it could be utilized to produce nanofibers containing Piper betle (L). Methods: The electrospinning was assembled with the main components were the 20 kV high voltage (hV) power supply (module), the Terumo TE-331 syringe pump and the collector. The resulting device was then evaluated for tool performance. The device was used to produce Polyvinyl Alcohol (PVA)-based nanofibers with Piper betle (L) as the active ingredient. The nanofibers produced were then tested for antibacterial activity, morphology by Scanning Electron Microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Results: The polymer solution was pushed by a syringe pump with a flow rate of 15 ml/h into the spinneret. In this electrospinning process, the formed nanofibers appear visually as a thin layer on the collector. With variation in PVA concentration and the same concentration of Piper betle l. as the active ingredient, the results showed that the nanofiber carrier did not affect the efficacy provided by Piper betle (L). The characterization with SEM revealed that the assembled tool was able to make nanofiber preparations that have fine continuous/fairly regular fibers with an average diameter of 46.479±2.406 nm. Meanwhile, the analysis using FTIR showed the presence of OH stretching groups of phenolic compounds from Piper betle (L). Conclusion: It can be concluded that the electrospinning was successfully assembled from unused medical devices in hospital and proven to produce nanofibers.

10 kV high-voltage DC power supply design with novel sliding-mode phase-shift controller for intense field dielectrics

10 kV high-voltage DC power supply design with novel sliding-mode phase-shift controller for intense field dielectrics

Optimizing the operation of a high-voltage power line in Turkmenistan considering climatic conditions

This scientific article is devoted to the optimization of a 500 kV high-voltage power line, taking into account the climatic characteristics of Turkmenistan. As a result of the research, it was found that with a nominal line voltage of 500 kV under standard weather conditions, the load losses were 11.45 MW, the corona losses were 0.76 MW and the total power losses were 12.21 MW, in dry snow, corona losses amounted to 2.98 MW, and total power losses amounted to 14.43 MW; in rainy weather, corona losses amounted to 9.76 MW, total power losses amounted to 21.21 MW, and during frosts, corona losses amounted to 26.02 MW, total power losses amounted to 37.47 MW. For this reason, to reduce power losses in the line Mary PPS – Serdar 500 kV for P=0.2Pnat value, it is recommended to keep the voltage at 1.05 Unat in standard weather conditions, at Unat value in dry snow, and at 0.95Unat in rain and frost.

Approximate method for calculating the magnetic field of 330-750 kV high-voltage power line in maintenance area under voltage

Problem. In order to organize effective protection of working personnel from the action of strong electromagnetic influence when performing work on live high-voltage power lines (HVPL), the existing methods of calculating the magnetic field (MF) need to be developed in the direction of their simplification during operational use. Goal. The purpose of the work is to develop an approximate method and a simplified methodology for calculating the magnetic field flux density near the surface of the 330-750 kV HVPL wires for the prompt determination of the safe distance of the working personnel to the surface of the HVPL wires at the current value of their operating current. Methodology. A new approximate method of calculating the flux density of the MF in the area of work on live HVPL based on the Biot-Savart law and determining the maximum values of the flux density of the MF on the axes of symmetry N of the suspension of N wires, which are decisive for the protection of working personnel, is proposed. Results. Exceeding the maximum acceptable level of the MF for individual power lines at their nominal currents, adopted in the European Union, and the need to implement measures to reduce MF were revealed. Originality. It is shown that the distribution of the 330-750 kV HVPL near N of its split wires with an error of no more than 2.5 % can be determined by the current of only one of the phases of the HVPL. This distribution of MF, which is uneven, is determined by the order of axial symmetry N with the maximum values of the flux density of the MF lying on the axes of symmetry N of the suspension of the phase wires. Practical value. The development of an approximate method and a simplified methodology for calculating the flux density of the MF near the surface of the wires of 330-750 kV HVPL, which allows you to quickly, without the use of a computer, calculate the safe distance to the wires of a specific HVPL at the current value of its operating current, as well as determine the necessary measures for the protection of personnel from the MF, which can be implemented either by physically limiting the minimum distance from the worker's body to the surface of the wires to a dangerous one, or by necessary reduction of the HVPL operating current during repair work. Verification. An experimental verification of the proposed method and methodology was carried out on a laboratory installation with a mock-up of a phase of a 330 kV HVPL from AC 400 type wires at 1500 A current, which confirmed the correctness of the proposed calculation relationships.

ANALYSIS OF FACTORS INFLUENCING THE INTENSITY OF TRANSFORMER OIL AGEING IN LONG-TERM OPERATION

The results of the analysis of influence of operational factors and peculiarities of transformer design on intensity of oxidative reactions of transformer oils in the tanks of 110 kV high-voltage power transformers are presented. As a result of two-way analysis of variance it was found that with increasing operating time there is a statistically significant increase in the value of the organic acid content in the oil. At the same time the rate of increase in the organic acids content in the transformer oil, operated under different conditions, significantly differs, which indicates a significant influence of operating conditions on the intensity of oxidative reactions. The results of two-way analysis of variance also show that the effects of changes in factor levels are not additive, that is, the effect of a change in the level of influence of one factor leads to a change in the effect of the level of influence of another. In other words, the process of oil oxidation is cumulative and a certain level of organic acids in the oil can be achieved either over a longer period of operation, but with relatively 'light' operating conditions, or over a shorter period of time, but with more 'heavy' operating conditions. In order to determine the factors most affecting the intensity of oxidative reactions, an analysis of the quality of filled oil, operating time, the influence of the region, the influence of the type and nominal characteristics of transformers on 6 data sets with identical rates of oxidative reactions was carried out. The results of the analysis show that the intensity of oxidation reactions is strongly influenced by the operating time, the transformer loading factors, the consumer composition (region of Ukraine) as well as the type and quality of oils. At the same time, factors such as rated capacity, type of transformer, number of windings, and the value of rated voltage on the medium and low voltage windings do not influence the intensity of oxidation of oils. The results obtained allow the correction of the maximum permissible values of oil acidity, taking into account the factors affecting the intensity of oxidation of oils.

Analysis of lightning disturbance at 150 kV high voltage power lines

The power transmission line channels electrical energy from power plants to consumers through diverse natural conditions. East Java is an area with a unique topography, where clouds causing rain and lightning are frequently formed. Such clouds strongly interfere with the 500 kV Extra High Voltage Line (SUTET), causing a lightning strikes. Therefore, the lightning strikes along the channel needed to be analyzed. The random method used in this research measured the lightning safety at the tower, within a quarter of the distance from the tower and half the distance from the tower (Lightning disturbance due to back flashover) Based on the calculation, the highest number of disturbances in the phase wire per 100 km2 of conductor per year has obtained and (SFO) was 1.073399.10-3. while tower impedance has found at 273.6219 Ohms.

Development of PC based automation of ion beam analysis and ion implantation experiments

This paper presents the details of a personal computer (PC) based automation of ion beam analysis and ion implantation experimental setup that has been developed and implemented in a 1.7 MV Tandetron accelerator. Hardware and software of the PC automated system were designed to automate multiple sample ion implantation, standard Rutherford Backscattering spectrometry (RBS), and High resolution Rutherford Backscattering spectrometry (Hi-RBS) experiments. The system uses in-house developed signal conditioning circuitry, isolation amplifiers, and transistor drivers along with cost-effective and off-the-shelf commercial components like a general purpose, multifunction data acquisition card, etc. A five axis goniometer is used for handling multiple samples and their automatic positioning according to the commands from the PC over RS232 interface. Key tasks carried out in the automation of system include control and mesurement of ion beam fluence, selection of backscattered particles through screening of their energies by controlling a set of +/−25 kV and −3 kV high voltage power supplies, controlled collection of backscattered yield using single and multi channel analysers, controlling the region-of-interest windows in the energy spectra and the cumulative counts in them. Controlling the position of the samples and facilitating the experiments on multiple samples, online display of energy spectra and its auto storage, and vacuum interlocking are also automatically done. This PC based setup has been automated using a windows based LabVIEW software making it easy to port the set up between different computer operating systems apart from achieving many other advantages like quick and easy development of versatile, multi-purpose, and user friendly graphical interface. Extensive tests carried out on the hardware established correct functioning of various modules of the hardware. The 0–10 V control inputs applied to the +/−25 kV and −3 kV high voltage power supplies were tested and seen providing an <0.1% accuracy, <0.05% linearity, very low drift of 50 ppm, 0.01% precision, and <1mv rms output noise. The software modules have been tested to check independent control and monitoring the irradiated dose, energy to voltage conversion, the multi channel analyser control in addition to other tasks such as computing the region-of-interest counts. The fluence computed from the pulse counts from the ion beam current integrator and the actual fluence were found to be matching within 0.1%. The vacuum interlocking scheme was tested covering a range of 10−5 mbar to 10−9 mbar. Hi-RBS was carried out on a 3 nm thick Ag film grown on Si substrate using 0.3 MeV H+ ion beam over a backscattered energy range of 10–300 keV for a fixed ion fluence 2 × 1012 ions/cm2 at each energy. The recorded spectrum showed well separated Si edge and Ag peaks. The energy resolution is calculated to be 1.2 keV and a relative energy resolution (ΔE/E) of ∼0.4% is obtained.

The controller and monitoring system of 1-10 kV high voltage power supply

The controller and monitoring system of 1-10 kV high voltage power supply was developed. The system composed of an Arduino mega 2560 microcontroller boards, a digital to analog conversion (DAC) part, a high voltage module and the designed software on a personal computer. The software was developed by LabVIEW software for controlled the high voltage module and displayed the high voltage values. The microcontroller board used for the digital data transmission to the DAC part and converted the high voltage value to digital data for monitoring. The DAC part generated the analog signal from a board for adjusting a high voltage value of a module. The completed system can be controlled the high voltage and the real-time monitored the high voltage value of a module with the resolution of 2.5 V. The error of actual high voltage values with the setting one was maximum of 5%

Review of Research Progress on the Electrical Properties and Modification of Mineral Insulating Oils Used in Power Transformers

In November 2017, the first ±1100 kV high-voltage direct-current power transformer in the world, which was made by Siemens in Nurnberg, passed its type test. Meanwhile, in early 2017, a ±1000 kV ultra-high voltage (UHV) substation was officially put into operation in Tianjin, China. These examples illustrate that the era of UHV power transmission is coming. With the rapid increase in power transmission voltage, the performance requirements for the insulation of power transformers are getting higher and higher. The traditional mineral oils used inside power transformers as insulating and cooling agents are thus facing a serious challenge to meet these requirements. In this review, the basic properties of traditional mineral insulating oil are first introduced. Then, the variation of electrical properties such as breakdown strength, permittivity, and conductivity during transformer operation and aging is summarized. Next, the modification of mineral insulating oil is investigated with a focus on the influence of nanoparticles on the electrical properties of nano-modified insulating oil. Recent studies on the performance of mineral oil at molecular and atomic levels by molecular dynamics simulations are then described. Finally, future research hotspots and notable research topics are discussed.

SYNTHESIS OF ACTIVE SCREENING SYSTEM OF MAGNETIC FIELD OF HIGH VOLTAGE POWER LINES OF DIFFERENT DESIGN TAKING INTO ACCOUNT SPATIAL AND TEMPORAL DISTRIBUTION OF MAGNETIC FIELD

Purpose. Analyze the spatial and temporal distribution of the magnetic field of high voltage power lines with different design allowing and development of recommendations for the design of active screening systems by magnetic field of high voltage power lines. Methodology. Analysis of the spatial and temporal distribution of the magnetic field of high voltage power lines of different design allowing is made on the basis of Maxwell's equations solutions in the quasi-stationary approximation. Determination of the number, configuration, spatial arrangement and the compensation coil currents is formulated in the form of multiobjective optimization problem that is solved by multi-agent multiswarm stochastic optimization based on Pareto optimal solutions. Results of active screening system for the synthesis of various types of transmission lines with different numbers of windings controlled. The possibility of a significant reduction in the level of the flux density of the magnetic field source within a given region of space. Originality. For the first time an analysis of the spatial and temporal distribution of the magnetic field of power lines with different types and based on findings developed recommendations for the design of active screening system by magnetic field of high voltage power lines. Practical value. Practical recommendations on reasonable choice of the number and spatial arrangement of compensating windings of active screening system by magnetic field of high voltage power lines of different design allowing for the spatial and temporal distribution of the magnetic field. Results of active screening system synthesis of the magnetic field of industrial frequency generated by single-circuit 110 kV high voltage power lines with the supports have 330 - 1T «triangle» rotating magnetic field with full polarization in a residential five-storey building, located near the power lines. The system contains three compensating coil and reduces the level of induction of the magnetic field source to the sanitary standards of 0.5 µT in almost of all the house space.

Hybrid wireless charging system for monitoring overhead 110 kV high‐voltage power line equipment based on magneto‐electric conversion

The monitoring equipment for overhead 110 kV high-voltage power lines plays an important role in the smart grid operations and may be required to work for years without maintenance; therefore, many varieties of energy harvesting devices have been investigated with a variety of problems remained though. In this study, a hybrid wireless power charging proposed system, integrated with magneto-electric and electric-electric conversion, is presented. It consists of an inductive energy harvesting device, an AC–AC frequency inverter, the transmitting and receiving coils, the rectifier systems connected in series, a wind turbine to drive the rotation of the receiving coils, etc. In particular, three receiving coils were designed for symmetrical disposition so that the angle between each pair of receiving coils was 120°. The design of the series rectifier circuit was explored to improve the input voltage level for charging the monitoring equipment more easily. The dynamic wireless power transfer system would bring about four energy-increased outputs with three symmetrical receiving coils when they were driven to rotate. The proposed scheme, born out of the existing methods of energy harvesting for monitoring equipment would provide stable and safe power at any time and it has been verified effectively by both simulation and experiment.

Spectrum Analyses and Diagnoses of 350 kV HVPS Ripples on High Intensity D–T Fusion Neutron Generator

The 350 kV high voltage power supply plays a significant role in the deuterium ion accelerator of high intensity D–T fusion neutron generator, which is designed to be a momentous experimental platform for nuclear energy researches. The ripples of the HVPS have a variety of negative effects on the output high voltage and the neutron yield. In this paper, the 350 kV HVPS ripples were analyzed by means of power spectrum density based on fast Fourier transform. A ripple measurement system with anti-interference measures is developed to acquire the ripples information at the four kinds of output high voltages. The distributions of different frequencies ripples on the HVPS components are obtained from the characteristic frequencies composition of the power spectrum density in accordance with ripples generation mechanism. Furthermore, numerous scientific decisions could be made on the use, maintenance and improvement of the HVPS on the basis of spectrum analyses and diagnoses results.

Simulation of voltage doubling rectifying circuit in 150 kV high-voltage inverter power supply

Simulation of voltage doubling rectifying circuit in 150 kV high-voltage inverter power supply

Genotoxic effects of electromagnetic fields from high voltage power lines on some plants.

Allium cepa bulbs were germinated in pots for three days on treatment area on which 380 kV high voltage power lines are passing. Ten bulbs were set up for each treatment area (0 m (meter), 10 m, 25 m, 50 m and 100+ m for control from power lines). Triticum baeoticum Boiss. subsp. baeoticum seeds were collected at same distance from power lines on planted field. Ten seeds from each area were germinated in Petri dishes for three days in laboratory. The treatment groups were compared with the control group for mitotic index and chromosome aberrations. Data obtained showed that electromagnetic fields from high voltage power lines increased the mitotic index and chromosome aberrations.

Evaluation of hormonal change, biochemical parameters, and histopathological status of uterus in rats exposed to 50-Hz electromagnetic field

This study investigates the effects of the electromagnetic field (EMF) resulting from the 170 kV high-voltage power lines on hormonal status, on progesterone and 17-beta estradiol levels, and on morphology of the uterus and ovaries associated with biochemical parameters of adult Wistar female rats. The rats were assigned to experimental (21) and control groups (7). The rats in the experimental group were housed in a wooden barn with 7.5 m vertical distance to the power line. Groups 1, 2, and 3 were exposed continuously (24 h) to electric-electromagnetic fields (ELF-EMFs) (48.21 +/- 1.58 mG) for 1, 2, and 3 months, respectively. The rats of group 4 served as the control and were placed in laboratory conditions (The average value of the ELF was 0.75 +/- 0.05 V/m. The value of the EMF was calculated to be 0.48 +/- 0.05 mG.). Significant (P < 0.05) decreases were determined among the groups in terms of reproductive organ weights (uterus and ovaries) and progesterone and estrogen levels in relation to the varying periods of the estrous cycle. Although marked reductions (P < 0.05) were observed among the groups in relation to plasma catalase activity, depending on exposure time, no significant differences were found in terms of glutathione and malondialdehyde levels. It is concluded that exposure to the ELF-EMFs for different time periods produced significant decreases in plasma catalase activities in the 3-month exposure groups but no effects on progesterone level, on 17-beta estradiol level, or on the morphology and weight of uterus and ovaries.

Riesgo para la salud por radiaciones no ionizantes de las redes de energía eléctrica en el Perú

We review most important national and international publication, specially those which has been conducted within the framework of the International Electromagnetic field Project of the World Health Organization, for known the biological and health effects of the electric energy fields. The level of population, residential and occupational exposure were revised in principal Peruvian evaluation of electricity services and system realized since 2002 to 2008 with representative samples which included more than 1400 locations measurement. Exposure evaluation showed that the highest exposure levels in Peru came from 220 kV high voltage power lines, However, in most cases (98%) are below the recommended limits. The risk assessment of non-ionizing radiation from electric power network in Peru shows that the health risk is not significant.

Design and Simulation for the Pulse High-Voltage DC Power Supply (HVPS) of 1.2 MW/2.45 GHz HT-7U Lower Hybrid Current Drive System

The superconducting tokamak HT-7U [1] has been designed by the Institute of Plasma Physics since 1998 and will be set up before 2003. The 1.2 MW/2.45 GHz HT-7U LHCD (Lower hybrid current drive) system which being the most efficient non-induction device can heat the plasma and drive the plasma current has been efficiently in operation now, and a particular design of the 2.8 MW/-35 kV high-voltage DC power supply has been already completed and will apply to the klystron of LHCD on HT-7 and the future HT-7U, and the project of the power supply has been examined and approved professionally by an authorized group of high-level specialist in the Institute of Plasma Physics. The detailed design of the power supply and the simulation results are referred in the paper.

Field-portable capillary electrophoresis instrument with potentiometric and amperometric detection

A portable capillary electrophoresis instrument which incorporates both potentiometric and amperometric detection in a single unit is presented. It includes lead acid batteries as independent power source, a 30 kV high voltage power supply and the detection electronics. With a size of 340 mm×175 mm×175 mm and a weight of 7.5 kg it can easily be carried by one person. Possible applications of the instrument are illustrated with the potentiometric detection of alkali and alkaline earth metal cations with coated-wire ion-selective electrodes and the amperometric detection of electroactive anions with gold electrodes. It is further demonstrated that amino acids may be determined with copper electrodes used in either the potentiometric or the amperometric mode.