ANALYSIS OF THE STATE OF INSULATION OF ELECTRICAL EQUIPMENT OF MINING AND METALLURGICAL COMPANIES

2020 ◽  
Vol 2 (1) ◽  
pp. 201-215
Author(s):  
R.V. KLYUEV ◽  
◽  
I.I. BOSIKOV ◽  
O.A. GAVRINA ◽  
K.S. KRYSANOV ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
High Altitude ◽  
Experimental Studies ◽  
Electrical Equipment ◽  
Insulation Resistance ◽  
Air Humidity ◽  
Electric Networks ◽  
Single Method ◽  
Underground Workings ◽  
Mathematical Processing

The paper presents the results of theoretical analysis and mathematical processing of experimental studies of the insulation state of individual elements of the same type of sections of 0.4 kV electric networks in underground workings conducted at the mining and processing mines at heights of workings up to 1000 m above sea level. The studies were carried out according to a single method in order to identify the effect of highlands on the insulation state of individual elements of 0.4 kV networks. It is recommended to complete scraper winches, fans and other mechanisms of high-altitude mines with organosilicon-insulated engines or with front coatings filled with top coat varnishes similar to excavator engines. A similar situation is noted with the launcher. More than 50 % of all the equipment of high-altitude mines have an active insulation resistance of less than 20 mOhm. A higher asymmetry of the total and active insulation resistance of launchers is noted. It is recommended to use silica gel to reduce air humidity inside the shells of the launcher...

Hypoxic mechanisms in primary headaches

Cephalalgia ◽  
2016 ◽  
Vol 37 (4) ◽  
pp. 372-384 ◽  
Author(s):  
Josefine Britze ◽  
Nanna Arngrim ◽  
Henrik Winther Schytz ◽  
Messoud Ashina
Keyword(s):  
Cluster Headache ◽  
High Altitude ◽  
Acute Mountain Sickness ◽  
Experimental Studies ◽  
Epidemiological Studies ◽  
Primary Headaches ◽  
Secondary Headaches ◽  
Novel Approach ◽  
Calcitonin Gene ◽  
Level Of Knowledge

Background Hypoxia causes secondary headaches such as high-altitude headache (HAH) and headache due to acute mountain sickness. These secondary headaches mimic primary headaches such as migraine, which suggests a common link. We review and discuss the possible role of hypoxia in migraine and cluster headache. Methods This narrative review investigates the current level of knowledge on the relation of hypoxia in migraine and cluster headache based on epidemiological and experimental studies. Findings Epidemiological studies suggest that living in high-altitude areas increases the risk of migraine and especially migraine with aura. Human provocation models show that hypoxia provokes migraine with and without aura, whereas cluster headache has not been reliably induced by hypoxia. Possible pathophysiological mechanisms include hypoxia-induced release of nitric oxide and calcitonin gene-related peptide, cortical spreading depression and leakage of the blood-brain barrier. Conclusion There is a possible link between hypoxia and migraine and maybe cluster headache, but the exact mechanism is currently unknown. Provocation models of hypoxia have yielded interesting results suggesting a novel approach to study in depth the mechanism underlying hypoxia and primary headaches.

scholarly journals Theoretical and experimental studies of a gas stamping device with a piston pressure multiplier

2019 ◽  
Vol 18 (1) ◽  
pp. 163-173
Author(s):  
A. Yu. Botashev ◽  
R. A. Bayramukov
Keyword(s):  
Theoretical Analysis ◽  
Experimental Studies ◽  
Fuel Mixture ◽  
Small Scale ◽  
Scale Production ◽  
Pressure Treatment ◽  
Energy Of Combustion ◽  
Stamping Process ◽  
Pressure Multiplier ◽  
The Matrix

In many industries, the share of small-scale production plants is significant. In these conditions, compared with traditional methods of pressure treatment, pulse pressure treatment methods, one of the varieties of which is gas stamping, are more efficient. However, the known devices of gas stamping provide mainly stamping of thin-walled parts. To expand the technological capabilities of gas stamping, the authors developed a gas stamping device with a piston pressure multiplier, in which heating and deformation of the stamping workpiece is carried out using the energy of combustion of fuel mixtures in the combustion chamber, in the working cylinder and in the cavity of the matrix. This article is devoted to the study of the workflow of this device. Theoretical analysis of the workflow was carried out, and, as a result, a pattern was determined for the variation of the pressure that performs the stamping process in the working cylinder. In particular, it was found that at the final stage of the stamping process, due to the energy of combustion of the fuel mixture, the pressure in the working cylinder increases 1.5...2 times, which allows a significant increase in the thickness of the parts to be stamped. An experimental gas stamping device with a piston pressure multiplier was developed, and experimental studies were carried out. The studies confirmed the main results of the theoretical analysis: the discrepancy between the theoretical and experimental values of the degree of pressure multiplication in the working cylinder does not exceed 11%.

scholarly journals AUTOMATION OF THE HEAT STATE ANALYSIS PROCESS HIGH-VOLTAGE CURRENT TRANSFORMERS

2019 ◽  
pp. 96-110
Author(s):  
V. M. Kutin ◽  
M. V. Nikitchuk ◽  
V. M. Svitko ◽  
O. O. Shpachuk
Keyword(s):  
Expert Knowledge ◽  
Thermal State ◽  
Statistical Processing ◽  
Electrical Equipment ◽  
Technical Condition ◽  
Mobile Systems ◽  
Electric Networks ◽  
Structural Element ◽  
Operating Life ◽  
Current Transformers

Thermographic control of electrical equipment allows you to draw preliminary conclusions about the technical condition of insulation, contact joints, windings, structural elements and cooling systems of electrical equipment of voltage classes 0.4 ÷ 750 kV. However, it should be borne in mind that the results of temperature measurement and assessment of the thermal state of electrical equipment are influenced by such factors as: environmental conditions, qualifications of personnel performing thermographic control and data interpretation, the need to improve regulatory documents for assessing the thermal state of electrical equipment and develop unified algorithms analysis of the results of thermographic examinations and gradation of the development of defects in electrical equipment. Modern research in the field of thermographic control of electrical equipment is developing in several directions, namely: the use of automated (stationary or mobile) systems for collecting thermographic data; development of algorithms for processing thermal images that reduce the influence of extraneous noise on the values of the measured temperatures, select the image of the object being examined, select the optimal level of contrast of the thermal image to detect thermal anomalies; using statistical processing of thermal fields of thermal monitoring objects and making decisions about the thermal state of equipment using neural networks, machine learning and expert knowledge. Automation of the analysis of thermographic control data is an urgent scientific and practical task, the solution of which will improve the quality of maintenance, repairs, extension of the operating life and operational management of electrical equipment in conditions of a significant level of aging of the main production assets of electric companies and change of generations of staff. Measuring current transformers of voltage classes 330 ÷ 750 kV are critical elements in the distribution schemes of electric power and in electric networks, and their technical condition directly affects the reliability of electric networks and power supply to consumers. The paper considers the reasons for the development of defects in current transformers of voltage classes 330 ÷ 750 kV, and also proposes relationships to take into account the influence of the air flow rate and the actual value of the emissivity of the structural element of the current transformers, as well as elements of the algorithms for analyzing data from thermal imaging surveys to reduce the influence of environmental factors and qualification level of the personnel performing the analysis, diagnostic results.

scholarly journals ELECTRIC SUPPLY OF UNDERGROUND CONSUMERS OF DEEP ENERGY-INTENSIVE MINES

2018 ◽  
pp. 25-46
Author(s):  
F. P. Shkrabets
Keyword(s):  
Power Supply ◽  
Supply Voltage ◽  
Maximum Load ◽  
Electrical Equipment ◽  
Transport Systems ◽  
Local Power ◽  
Electrical Networks ◽  
Electric Networks ◽  
Supply Networks ◽  
Technical And Economic Indicators

The increase in the capacity of cleaning and construction vehicles for highcapacity and energy-intensive mines calls for an increase in the  supply voltage of cleaning and tunneling combines, as well as  transport systems: from a voltage of 660 V switched to 1140 V, and  now to 3300 V. This allows improving technical and economic  indicators for clearing and access areas, as well as improving the reliability of local Power Supply Systems (PSS). However, this  trend prevents the supply of underground electric networks with a  voltage of 6 kV, in connection with which the problem arises of  increasing the voltage of supply networks. To date, it has become  possible to apply the 10 kV voltage to the operation, which is most  acceptable for the use of electrical equipment for electrical networks  and protection devices. Leading educational, research and design  organizations were engaged in research on this issue. An analysis of the results of the research showed that switching to 10 kV voltage is  justified and timely. At the same time, 35 kV voltage is not removed  from the agenda, which is technically feasible and economically  justified, but there are problems with the safety of its operation in  underground workings, which requires appropriate refinement. This  level of voltage will improve the quality of electricity.Conclusions: 1. Application of 35 kV voltage in the underground power supply system of coal and ore mines is advisable at a depth of more than 1000 m with a maximum load of at least 1000 kVA at the  level of the stem cables.2. Application of 35 kV voltage in underground electrical networks will allow to significantly improve the quality indicators of voltage,  reliability, and economy of the system due to the current unloading  of the most important element of SES, such as stem cables.3. Analysis of the main parameters and characteristics of electrical mine electrical equipment gives reason to believe that it allows  implementing a trend of 35 kV deep input to deep horizons of mines  (mines) and placement of 35/6 kV substations on working horizons.

Experimental study of the possibilities of the production complex for diagnosing the operability of the electrical equipment system of cars

2020 ◽  
Keyword(s):  
Experimental Study ◽  
Experimental Studies ◽  
Electrical Equipment ◽  
Electrical System ◽  
Production Complex ◽  
Equipment System

The paper presents the results of experimental studies of the developed production complex for diagnosing the efficiency of electrical equipment of cars. Keywords automotive, automobile, diagnostics, electrical system

The most common violations of regulatory indicators of the quality of electric energy in electric networks

2021 ◽  
pp. 44-49
Author(s):  
A. G. Soshinov ◽  
T. H. Aisin
Keyword(s):  
Quality Indicators ◽  
Electric Energy ◽  
Electrical Equipment ◽  
Operating Conditions ◽  
Regulatory Requirements ◽  
Electric Networks ◽  
High Quality ◽  
The Asymmetry

Work on ensuring the quality of electric energy in accordance with the requirements of GOST 32144-2013 is currently relevant and requires prompt and high-quality solutions. The article lists the main consumers of electric energy that negatively affect its quality, provides the results of measurements of electric energy quality indicators and the most common violations of regulatory requirements, analyzes the influence of voltage asymmetry on the operating conditions of electrical equipment. The basic formulas for calculating the asymmetry coefficients and ways to reduce the voltage asymmetry are proposed.

scholarly journals Justification of the active method of protecting the insulation of submersible electric motors

2019 ◽  
Vol 124 ◽  
pp. 02003
Author(s):  
V. A. Trushkin ◽  
O. N. Churlyaeva ◽  
R. V. Kozichev
Keyword(s):  
Physical Properties ◽  
Electrical Breakdown ◽  
Electrical Equipment ◽  
Working Environment ◽  
Operating Parameters ◽  
Insulation Resistance ◽  
Electric Motors ◽  
Electrically Conductive ◽  
Active Method ◽  
Conductive Properties

The article provides an analysis of the properties of the working environment of submersible electrical equipment. The influence of the operating parameters of electrical equipment on the physical properties of the fluid (its electrically conductive properties) is considered. Mathematical confirmation of the implementation of electroosmosis in the capillaries of the insulation of submersible electric motors is given. The rationale for the active method of protecting submersible electrical equipment from reducing insulation resistance and preventing electrical breakdown is given.

scholarly journals Study on Impedance Characteristics of Aircraft Cables

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Weilin Li ◽  
Wenjie Liu ◽  
Xiaobin Zhang ◽  
Zhaohui Gao ◽  
Meng Xie ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Power System ◽  
Electric Power ◽  
Electrical Equipment ◽  
Electric Power System ◽  
Normal Operation ◽  
Variable Frequency ◽  
Forming Mechanism ◽  
Changing Trends ◽  
Impedance Characteristics

Voltage decrease and power loss in distribution lines of aircraft electric power system are harmful to the normal operation of electrical equipment and may even threaten the safety of aircraft. This study investigates how the gap distance (the distance between aircraft cables and aircraft skin) and voltage frequency (variable frequency power supply will be adopted for next generation aircraft) will affect the impedance of aircraft cables. To be more precise, the forming mechanism of cable resistance and inductance is illustrated in detail and their changing trends with frequency and gap distance are analyzed with the help of electromagnetic theoretical analysis. An aircraft cable simulation model is built with Maxwell 2D and the simulation results are consistent with the conclusions drawn from the theoretical analysis. The changing trends of the four core parameters of interest are analyzed: resistance, inductance, reactance, and impedance. The research results can be used as reference for the applications in Variable Speed Variable Frequency (VSVF) aircraft electric power system.

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