Electric Power Installations Research Articles

Разработка критериев надежности и оценки технического состояния роторов в опорах на подшипниках скольжения в условиях эксплуатации

The problems of methodical improvement in the application of shaft sensors for the systems of vibration control, monitoring and automatic diagnostics of a technical state of power plants are considered. The assessment of a current standard basis for vibratory control systems is given and its imperfection for the assessment of the technical state of rotors and turboset bearings is shown. The criteria for vibration reliability of rotors and bearings of turbosets with their rotors supported by slider bearings are offered. The criteria for the evaluation of a technical state and vibration reliability of rotors under operation conditions take into account the application of a complete system of shaft sensors in accordance with RSS 55263-2012. The criteria formulated are necessary for the as-sessment of a technical state in modern systems of automatic diagnostics. In addition to conventional vibration parameters (according to RSS 55263-2012 and RSS 55265.2-2012) there are offered in addition about two tens of parameters. Besides there are offered boundary values of these parameters exceeding ones reduces a vibration reliability and general reliability of shafting. The criteria are obtained on the basis of experimental and rated works by the authors for turbosets of 60-1200MWt TES and APP. The concept for the improvement of the systems of monitoring and automatic diagnostics for electric power installations with the use of shaft sensors is offered. The examples of modeling a number of defects at starting and stationary work are shown.

Numerical Simulation of Temperature Distribution Field in Beam Bulk in the Simultaneous Presence of Heat Insulation, Heat Flux and Heat Exchange

Most of the bearing elements of electric power installations operate in the presence of local cold insulator, heat flow, and heat transfer. To ensure the smooth operation of these elements it is necessary to develop appropriate computational algorithms and methods that allow to investigate numerically the thermomechanical condition of bearing elements. Besides, obtained numerical results should have different precision and respectively describe such a complex exceptional nonlinear process under study. Under the established process for the length of the test rod bearing element temperature field, displacement field, elastic, thermal and thermoelastic stress components field will arise. To determine these decisions, taking into account natural conditions and maintenance, we should use the techniques oriented on the basic laws of conservation of energy [1, 2].

発弧用金属線の材質と太さが耐アーク試験時のアークエネルギーに及ぼす影響

SUMMARY Metal wires are widely used for arc ignitions in power arc tests on electrical power installations, and their material and thickness are selected variously. However, the material and the thickness of the metal wire are thought to be influential factors in the severity of the power arc test, because they may change the arc duration and the physical characteristics of arc. Therefore it is important to understand the dependence of the severity of the power arc test on the material and the thickness of the metal wire. In this paper, we made the experiment, where arcs were generated in a closed chamber with changing the material and the diameter of the metal wire for arc ignition. By this experiment, we clarified the fusing characteristics for various metal wires, and then studied how the material and the thickness of the metal wire influence the arc energy for the first half-cycle of current. As a result of this study, we pointed out a possibility of changing the severity in the power arc test according to the metal wire for arc ignition.

Automatic Power Supply for Residential Consumer Using Microgrid with Hybrid Power Supply

Abstract. This paper proposes a Power Management System (PMS) designed to supply continuous power for residential using low voltage Microgrid. The Microgrid equipped with a hybrid power supply includes, battery storage system and three power supplies: a wind mill, photovoltaic (PV) emulator and proton exchange membrane (PEM) fuel cell (FC). The connections of the energy resources to the common ac bus make use of power inverters with specific functionalities. The automatic power management system for the operation and control of the distributed energy resources connected to residential electric power installations, taking into account both the grid connected operating mode and the islanded operating mode. The PMS provides rapid response to support the critical load. It can also operate as a standalone system in case of grid failure like an incessant power supply. The operating behavior of the proposed automatic system is simulated by using MATLAB SIMULINK.

Human Exposure to Electromagnetic Fields Produced by Distribution Electric Power Installations

The long term effects of electromagnetic fields on the human body are far from being well understood. Special concerns arise if this exposure is relatively prolonged such as in the cas ...

Feasibility of a Dual-Fuel Engine Fuelled with Waste Vegetable Oil and Municipal Organic Fraction for Power Generation in Urban Areas

Biomass, in form of residues and waste, can be used to produce energy with low environmental impact. It is important to use the feedstock close to the places where waste are available, and with the shortest conversion pathway, to maximize the process efficiency. In particular waste vegetable oil and the organic fraction of municipal solid waste represent a good source for fuel production in urban areas. Dual fuel engines could be taken into consideration for an efficient management of these wastes. In fact, the dual fuel technology can achieve overall efficiencies typical of diesel engines with a cleaner exhaust emission. In this paper the feasibility of a cogeneration system fuelled with waste vegetable oil and biogas is discussed and the evaluation of performance and emissions is reported on the base of experimental activities on dual fuel heavy duty engine in comparison with diesel and spark ignition engines. The ratio of biogas potential from MSW and biodiesel potential from waste vegetable oil was estimated and it results suitable for dual fuel fuelling. An electric power installation of 70 kW every 10,000 people could be achieved.

New electric‐shock job exposure matrix

To evaluate a consistent association between jobs in "electric" occupations and amyotrophic lateral sclerosis (ALS), a comprehensive job exposure matrix (JEM) that includes electric shocks and magnetic fields (MF) is needed. We used incident electric shocks and electrocutions from two available data sources along with expert judgment to create a JEM that was integrated into an existing MF JEM. The final JEM contained ordinal electric-shock exposure assignments for 501 job titles. Main occupational groups experiencing the electric shocks were precision production, craft, and repair occupations. Specific jobs with the highest proportion of shocks per 100,000 workers were: electrical apprentices (99.7), mechanic and repairer helpers (74.0), hoist and winch operators (63.3), and electrical power installers (52.4). Examples of job titles with low electric-shock exposures were administrative support occupations, data-key entry operators, and waiters and waitresses. Combining publicly available data with an expert panel is a viable method to construct an electric-shock MF JEM. This JEM will allow an evaluation of association between electric shocks and neurodegenerative diseases.

The 42+ T Hybrid Magnet Project at CNRS-LNCMI-Grenoble

Hybrid magnets, the combination of a resistive inner coil with a superconducting outer one, allow to generate the highest continuous magnetic fields for a given electrical power installation. A new superconducting coil outsert has been designed to be integrated in the existing infrastructure at LNCMI-Grenoble (GHMFL). Based on the specific development of a Nb–Ti Rutherford Cable On Conduit Conductor (RCOCC) cooled at 1.8 K by a bath of superfluid helium at atmospheric pressure, the superconducting coil aims to produce a continuous magnetic field of 8.5 T in a 1.1 m bore diameter. Combined with resistive insert coils, an overall continuous magnetic field of 42+ T will be produced in a 34 mm warm aperture. The main results of the conceptual study will be presented together with first developments and tests of the RCOCC.

Scientific and technical complex for modeling, researching and testing of rocket-space vehicles’ electric power installations

In the given article scientific and technical complex for modeling, researching and testing of rocket-space vehicles’ power installations which was created in Power Source Laboratory of National Aerospace University “KhAI” is described. This scientific and technical complex gives the opportunity to replace the full-sized tests on model tests and to reduce financial and temporary inputs at modeling, researching and testing of rocket-space vehicles’ power installations. Using the given complex it is possible to solve the problems of designing and researching of rocket-space vehicles’ power installations efficiently, and also to provide experimental researches of physical processes and tests of solar and chemical batteries of rocket-space complexes and space vehicles. Scientific and technical complex also allows providing accelerated tests, diagnostics, life-time control and restoring of chemical accumulators for rocket-space vehicles’ power supply systems.

High-plasticity heat-resistant 03Kh14G16N6Yu-type steels with heat-and deformation-resistant austenite

The structure and mechanical properties of 03Kh14G16N6Yu-type austenitic steels alloyed by molybdenum, tungsten, vanadium, and zirconium are studied after normalization at 1075°C and long-term holding at 500–700°C. The chemical composition of these steels ensures the resistance of their austenite to the martensitic transformation in the temperature range from 1200 to −196°C and during cold plastic deformation at a reduction of up to 60%. The best combination of the mechanical and technological properties is achieved in a 03Kh15G17N6YuVF steel with 0.08% W and 0.12% V. Long-term (up to 1000 h) holdings at 550–750°C do not cause the precipitation of carbide, nitride, and intermetallic phases in this steel. The long-term strength of the 03Kh15G17N6YuVF steel at temperatures up to 650°C is comparable with and its plasticity and impact toughness are higher than those of high-nickel Kh16N9M2 and Kh16N12M2 steels, which are applied in the main parts of electric power installations.

Fast Analytical Computation of Power-Line Magnetic Fields by Complex Vector Method

The electromagnetic environment related to electric power installations is typically evaluated by numerical integration methods. Numerical techniques, although powerful, are not well suited for assessing the dependence of the field strength on electric and geometric parameters. In this paper, a fast procedure to analytically evaluate power-line magnetic fields, based on complex vectors, is proposed. The use of complex algebra greatly simplifies analytical calculations compared to other approaches proposed in literature, allowing also complex conductor arrangements to be taken into account. A general formula for the magnetic-field intensity of any multiphase single-circuit line configuration is obtained. An expression for practical three-phase line configurations is simply derived as a particular case of the general formula. The proposed approach is then extended successfully to double-circuit lines, taking the load differences between circuits into account. Approximate formulas are validated by comparing magnetic flux density values with those computed from the general expression.

Decommissioning of Diesel-Fueled Electric Power Generators in Developing Countries

The interplay of electricity supply, enterprise development, air pollution, and human health is manifested in many developing countries. Most developing countries are striving to improve their industrial output and standard of living, within their national economic development programs and the Millennium Development Goals MDGOs . The availability of sustainable energy systems for powering industrial and civil facilities has emerged as a key determinant of the success of critical economic development programs. Because of the desirability of spreading development to rural areas to stem human migration to cities that have inadequate facilities and poor national electricity grids, many system planners in developing countries target distributed energy generation. Such distributed sources, which need to be managed locally but interlinked nationally for integration into national economic development programs, can be configured to power the many factories, schools, health facilities, and other industrial sectors that must be developed to improve socioeconomic conditions in developing countries. Currently, the primary source of electric power in most rural areas in developing countries is the diesel-fueled generator. This engine is ubiquitous in both urban and rural areas. The transportation and storage of diesel fuel for its use are required for a continuous supply of electricity. Unavailability and unaffordablity of fuel, especially in far-flung rural communities, often result in interruptions of the electric power supply and temporary cessation of power in dependent industrial operations. There is also the issue of air pollution by power generators that have been in commission for too long. Many fatalities result each year because people living in poorly ventilated houses operate generators indoors and inhale noxious fumes. In some countries where the price of fuel is excessively high particularly in non-oil-producing countries , dependence on diesel-fueled generators as the primary source of electricity supply can raise the cost for small businesses to produce goods and services to levels of unsustainability. As much as 40% of production costs have been attributed to energy investments in the operation of some factories in developing countries. The net effect of this circumstance is that these factories—some of which are established through microcredit schemes, thrift arrangements, direct lending, and community financing—may not be financially sustainable, resulting in inability to meet regional sustainable development targets. Development of large-scale electric power installations—most of which could be based on sustainable energy systems such as hydroelectricity, geothermal processes, wind farms, and gas-fired systems—is necessary. The implementation of these power generation systems, which is targeted in most strategic electricity supply plans of the developing countries, needs to complemented by adequate power transmission and distribution systems. These are requirements for decommissioning diesel-fueled electric power generators that have attendant economic, environmental, and health disadvantages in developing countries. Of course, as implied herein, grid electricity from large-scale installations would be available at costs that are lower than that of small, isolated generators. An additional option in rural or neighborhood electricity supply is to develop small generating facilities by using locally available resources, such as biomass, sunlight, and wind. As national, regional, and global development agencies and banks configure economic development plans and projects with sustainability requirements, local capacity for exploring options should be engaged or developed. Often such options can be fully assessed only through targeted research. It requires involving some local stakeholders to promote program and project sustainability.

Hydrogen Degradation of the Refinery and Electric Power Installations

Hydrogen Degradation of the Refinery and Electric Power Installations

Investigation of a model HTSC transformer with amorphous alloy cores

There are presented the main principles of development of HTSC transformer intended for the individual tests and for investigation within the electrodynamic model of a power network and within the independent electric power installation. The model single-phase transformer incorporates two concentric HTSC windings and circular cores of amorphous alloy and anisotropic steel tapes. It was tested in LN 2 medium and permits to evaluate the developed technological processes. Experimental investigations showed amorphous alloys display relatively low level of losses in the magnetic core as compared to anisotropic steel. The combination of epoxy impregnated fiber glass tapes and liquid nitrogen showed acceptable electrical properties of electrical insulation of HTSC windings. The critical current of the windings was close to the critical current of short samples of Bi-2223 tape.

Insulation co-ordination for continuous operating voltages and temporary overvoltages

This paper presents an approach to the insulation co-ordination of electric-power installations in the scope of the continuous operating voltages and temporary overvoltages; this approach opens the possibility to calculate the necessary required withstand voltages of unit insulations for short-duration (1 min) power-frequency test voltage, with respect to continuous operating voltages and power-frequency temporary overvoltages and the necessary reliability of the operation of high-voltage power system installations.

High electric field measurement and ice detection using a safe probe near power installations

The present study concerns an optical device measuring electric field by using a lithium niobate (LiNbO 3) crystal as the sensing medium, without any electrodes. Such a device has the advantage of providing a good galvanic insulation of materials and persons. A likely application is the high electric field measurement near electric power installations (frequency 50–60 Hz). The principle of measurement implements the electro-optic effect in the crystal. The sensing medium has been designed—thanks to finite element simulations—and a probe prototype constructed, with which measurements can be made far away through optical fibers. Experimental setups are developed in order to validate the physical principle, and also to calibrate the probe. As simulation results are in good agreement with experimental results, the behavior of the probe in a real environment is presented. Finally, the use of the probe to detect ice accretion on high power electric cables is proposed and validated.

Ventilation by natural convection of a one-story building

The objective of the present paper is to study passive ventilation of a one-story detached building. The flow of air is induced by a hot element of the building heated by solar energy. The hot element could be a part of a roof or a wall of the building, or a chimney through which the air is sucked from the building. The method does not require electrical power or mechanical installations, thus it can be applied in remote areas and buildings that are not connected to electric power, like desert-located buildings. The method may be used also for removal of toxic gases, like radon, from the ground floor of the building, without additional expenses. Experiments and simulations have been performed, in steady and transient states, in a scaled-down laboratory model. The results obtained from the simulations and fully supported by measurements and visualization, indicate that it is possible to obtain effective ventilation by the proposed method. Numerical simulations for steady and transient ventilation in real-size buildings are presented and discussed.

Interaction of Environmental ELF Electromagnetic Fields with Living Bodies

The subject of potential environmental hazard due to the exposure to extremely low frequency (ELF) magnetic fields produced by electric power installations is receiving worldwide attention. This paper is a contribution to the assessment of that hazard by evaluating the induced electric fields and currents due to the nonuniform magnetic fields distribution along the height of a human. The effect of magnetic field orientation relative to the body posture is examined and the subsequent variation of the induced electric field in the human body is evaluated. Also, the paper accounts for the electric field coupling of a human in contact with the ground. A comparative study of induced magnetic and electric fields within a grounded human beneath different power lines is made and its results are discussed.

Feasibility of lime treatment at the Leviathan Mine using the in-line system

The In-Line System (ILS) was used in a pilot-scale water treatment study at the Leviathan Mine in California. The LeviathanMine is a remote, abandoned, copper/sulfbr mine. This study addressed two questions: (1) Can the severely polluted mine drainage at the Leviathan Mine be treated with lime to an acceptable quality? and (2) Can a neutralizing reagent formulation (using various ratios of lime, fly ash, and cement) be designed to improve the physical characteristics of the resulting sludge for disposal purposes? The primary pollutants of concern are arsenic, nickel, aluminum, iron, and sulfate. Pilot-scale studies at the Leviathan Mine show that an in-line system (ILS) can be used to treat the severely polluted pond and adit water to meet the U. S. Environmental Protection Agency's National Ambient Water Quality for Freshwater Aquatic Life Protection (l -hour acute toxicity) criteria. Lime and lime-based admixtures were used to neutralize the adit and pond waters. The optimal treatment pH range was 6.9-7.9 for adit water, and 6.5- 8.0 for pond water. The ILS served as a neutralization and mixing system for treating both water sources, and also as an aeration system for treating the adit water. The ILS effectively oxidized nearly 900 m@ of Fe+* within 30 seconds of contact time when treating the adit water. Additional work is needed to evaluate sludge alternatives. The simplicity, portability, flexibility, and economics of the ILS make it a prime candidate for remote treatment operations such as the Leviathan Mine. Furthermore, the ILS can operate by water power with elevational differences of 50 ft or greater. The need for permanent electrical power installation for water treatment can possibly be eliminated by coupling the ILS with a commercially available water-powered lime feed system.

Neuroblastoma and parental occupation.

We evaluated parental occupation and the risk of neuroblastoma using data from a large case-control study conducted by the Children's Cancer Group and the Pediatric Oncology Group. We compared the distribution of 73 paternal and 57 maternal occupational groups among 504 newly diagnosed cases of neuroblastoma and individually matched controls obtained by telephone random digit dialing in the United States and Canada. An increased risk of neuroblastoma was found for fathers employed as broadcast, telephone and dispatch operators (odds ratio [OR] = 6.1; 95% confidence interval [CI] = 0.7-50.9), electrical power installers and power plant operators (OR = 2.7; CI = 0.9-8.1), landscapers and groundskeepers (OR = 2.3; CI = 1.0-5.2), and painters (OR = 2.1; CI = 0.9-4.8). Elevated odds ratios were found for mothers employed as farmers and farm workers (OR = 2.2; CI = 0.6-8.8), florists and garden store workers (OR = 2.4; CI = 0.6-9.9), hairdressers and barbers (OR = 2.8; CI = 1.2-6.3), electric power installers and power plant operators, and sailors, fishers, and railroad workers. No increase in risk was found for other paternal occupations previously associated, including electricians, electrical equipment assemblers and repairers (OR = 1.1; CI = 0.6-2.0), or welders (OR = 0.5; CI = 0.1-1.6). The study reinforced some prior evidence of increased risks in electrical, farming and gardening, and painting occupations, but failed to confirm other previously reported associations. Further analyses of exposure to electromagnetic fields, metals, solvents, and pesticides are currently under way.