Graphene nanoplatelets electrical networks as highly efficient self-heating materials for glass fiber fabrics

2020 ◽  
pp. 152808372093148
Author(s):  
R Moriche ◽  
MA Moreno-Avilés ◽  
A Jiménez-Suárez ◽  
SG Prolongo ◽  
A Ureña
Keyword(s):  
Glass Fiber ◽  
Electrical Network ◽  
Maximum Temperature ◽  
Weak Links ◽  
Fiber Direction ◽  
Electrical Networks ◽  
Self Heating ◽  
Higher Temperature ◽  
Fiber Fabric

Self-heating GNPs-based electrical networks were successfully obtained for their use in electrothermal applications. The electrical resistance of the GNPs-networks created on glass fiber fabrics was strongly dependent on fiber direction. The electrothermal response was fast and the maximum temperature was achieved in the system after ∼20 s. Increments in temperature above 80°C were obtained at the surface of the coated glass fiber fabric at relatively low intensity currents. Cyclic self-heating did not cause appreciable diminution in performance. Additionally, their potential application in evaluation of the quality of dispersion of the nanoreinforcement was demonstrated, as regions with lower contents in GNPs showed higher temperature due to weak links between GNPs located in highly conductive paths forming the electrical network.

Study of the influence of overvoltage on the quality of electricity in energy systems.

2020 ◽  
Vol 23 (2) ◽  
pp. 52-58
Author(s):  
S. SKRYPNYK ◽  
Keyword(s):  
Power Supply ◽  
Fire Hazard ◽  
Lightning Discharge ◽  
Quality Standard ◽  
Normal Operation ◽  
Electrical Network ◽  
Modern World ◽  
Electrical Networks ◽  
The World

Our world with its high technologies has long been deeply dependent on the quality of electricity supply. In most countries of the world there are national power grids that combine the entire set of generating capacity and loads. This network provides the operation of household appliances, lighting, heating, refrigeration, air conditioning and transport, as well as the functioning of the state apparatus, industry, finance, trade, health services and utilities across the country. Without this utility, namely electricity, the modern world simply could not live at its current pace. Sophisticated technological improvements are firmly rooted in our lives and workplaces, and with the advent of e-commerce began the process of continuous transformation of the way individuals interact with the rest of the world. But with the achievement of intelligent technologies, an uninterrupted power supply is required, the parameters of which exactly meet the established standards. These standards maintain our energy security and create a reliable power system, that is maintaining the system in a trouble-free state. Overvoltage is the deviation of the rated voltage from the value of the corresponding quality standard (frequency, sinusoidal voltage and compliance of harmonics). Overvoltage in terms of fire hazard is one of the most dangerous emergency modes of electrical equipment, which causes conditions that in most cases are sufficient for the occurrence of fire hazards (exceeding the allowable voltage leads to disruption of normal operation or possible ignition). Against the background of deteriorating engineering systems, increased power consumption and poor maintenance, power supply of electrical installations, the main causes of overvoltage in electrical networks are thunderstorms (atmospheric overvoltage), switching switches, uneven phase load in electrical networks, etc. The physical picture of internal overvoltage is due to oscillatory transients from the initial to the established voltage distributions in the conductive sections due to the different situation in the electrical circuit. In the conditions of operation of electric networks planned, mode or emergency situations are possible. Therefore, the ranges of overvoltage are determined by the range from several hundred volts to tens and hundreds of kilovolts, and depend on the types of overvoltage. Atmospheric overvoltage is considered to be one of the most dangerous types of emergency modes of operation of the electrical network. This overvoltage occurs as a result of lightning discharge during precipitation by concentrating electricity on the surface of the object, the introduction of potential through engineering networks and

Approach to the location of distributed generation sources in the structure of electrical networks

2021 ◽  
pp. 75-86
Author(s):  
A. Gai ◽  
◽  
V. Gulevich ◽  
Keyword(s):  
Electric Power ◽  
Quality Indicators ◽  
Distributed Generation ◽  
Power Supply ◽  
Alternative Energy ◽  
Electric Power Industry ◽  
Energy System ◽  
Electrical Network ◽  
Electrical Networks

Today, the electricity supplier is not able to declare the possible level of quality of electricity supply, and the consumer simply does not have the opportunity to buy such "high-quality" electricity. In such conditions, a differentiated approach to tariff formation is inevitable, which has been implemented in practice today, albeit in its infancy. Further improvement of the tariff-forming mechanism is impossible without creating a "flexible" dependence of the tariff on the quality indicators of the consumer's power supply. Quality indicators, in turn, are based, on the one hand, on the methods and approaches for their determination, and on the other, on statistically reliable data on the elements that make up the equipment in the "generation-consumer" chain. In recent years, there has been a tendency to change the concept of development of the electric power industry, since preference is given to the development of sources of distributed generation. Distributed generation is understood as a source of electrical energy directly connected to the distribution electrical network or connected to it by consumers. Ensuring the socio-economic stability of society and a decent quality of life for the population largely depends on the reliability and efficiency of the functioning of the infrastructure for the supply of fuel and energy resources, in particular, electricity. Excessive losses of electricity during its production, transportation and distribution, as well as an unacceptable level of harmful emissions into the atmosphere, are the cause of interruptions in power supply to consumers and even the threat of systemic accidents in the United Energy System (UPS) of the country. The introduction of alternative energy sources in electric power systems, in addition to reducing the harmful impact on the environment and solving the problems associated with waste pollution during electric power generation, will reduce the use of natural resources and relieve the backbone and distribution power lines. As part of the scientific search, an approach was proposed, which is the basis for calculations to determine the optimal installation locations for sources of distributed generation of an average overhead line. The results obtained are presented in the framework of a joint technical meeting of leading specialists of operating enterprises, the customer and the staff of the Department of Power Supply named after V.M. Sinkova NULES of Ukraine.

scholarly journals КОМПЛЕКСНЕ ОЦІНЮВАННЯ ЕФЕКТИВНОСТІ ВСТАНОВЛЕННЯ ДОДАТКОВИХ ДЖЕРЕЛ РЕАКТИВНОЇ ПОТУЖНОСТІ У РОЗПОДІЛЬНИХ ЕЛЕКТРИЧНИХ МЕРЕЖАХ

2018 ◽  
Vol 124 (4) ◽  
pp. 103-111
Author(s):  
В. В. Кулик ◽  
О. Б. Бурикін ◽  
В. М. Пірняк
Keyword(s):  
Reactive Power ◽  
Comprehensive Evaluation ◽  
Efficiency Index ◽  
Electrical Network ◽  
Electrical Networks ◽  
Power Sources ◽  
Search Area ◽  
Electrical Grids ◽  
Monitoring Devices

To develop a method for assessing the effectiveness of reactive power sources (RPS) in electrical grids. The efficiency indicator was obtained as a result of combining the method of assessing the quality of the functioning of electrical grids on the basis of Markov networks and the method of interval analysis of energy losses. The efficiency index improves the formulation of the problem of optimizing the connection of the RPS to electrical networks. It improves the quality of this task. A new method of forming an indicator of the guaranteed effectiveness of the installing the RPS is obtained. It provides an unambiguous comprehensive evaluation of efficiency, takes into account the reliability of the electrical network, the quality of the voltage in its nodes, the accuracy of calculating the released and lost electricity. The method makes it possible to construct more efficient algorithms for optimizing the connection of RPS. They allow excluding from the search area optimal solutions "indefinite" fragments of the network without the help of an analyst. Estimation of the real effect is difficult or impossible for such fragments due to frequent failures or lack of monitoring devices. This correction of the search area improves the quality of the solution.

Mobile Measuring Complex for Conducting an Electric Network Survey

2020 ◽  
pp. 243-267 ◽  
Author(s):  
Alexander Vinogradov ◽  
Vadim Bolshev ◽  
Alina Vinogradova ◽  
Maxim Borodin ◽  
Alexey Bukreev ◽  
...  
Keyword(s):  
Electrical Network ◽  
Electrical Networks ◽  
Energy Audit ◽  
Power Networks ◽  
Operating Modes ◽  
Electric Transmission ◽  
Measuring Complex ◽  
Electric Transmission Line ◽  
Required Quality

An energy audit of the electrical network is required in the process of constructing new electrical networks as well as in justifying the reconstruction need of existing ones. In this chapter, the structure of a mobile measuring complex has been developed to conduct an electrical network survey without disconnecting consumers. The complex can be used to inspect 0.4 kV electrical networks and microgrids of the same voltage class and allows data collection on voltage losses and electric power losses in network elements such as a power lines (electric transmission line), and power transformers. The energy audit is conducted without disconnecting consumers in order to avoid an undersupply of electricity as well as to determine the real operating modes of power networks. Ultimately, the use of the developed measuring complex will increase the reliability of the power supply to consumers and ensure the required quality of the electricity supplied to them.

scholarly journals On the Mutual Influence of Voltage Control Modes and the Compensation of Reactive Power in the Electrical Networks of Industrial Enterprises

2021 ◽  
Vol 64 (3) ◽  
pp. 239-249
Author(s):  
V. P. Schasny ◽  
A. I. Zhukouski
Keyword(s):  
Power Supply ◽  
Reactive Power ◽  
Mutual Influence ◽  
Voltage Control ◽  
Reactive Power Compensation ◽  
Electrical Network ◽  
Electrical Networks ◽  
Industrial Enterprises ◽  
Technical Requirements

The efficiency of an enterprise’s power supply system depends on the quality of electricity and the losses of the latter in electrical networks; both being largely determined by the modes of voltage control and reactive power compensation. In practice, the problems of voltage control and reactive power compensation in power supply systems of industrial enterprises, including electric networks with a voltage of up to 1 kV, as well as 6, 10 kV and higher, are often solved separately. It triggers an irrational use of existing voltage control devices, underutilization of the installed capacity of compensating devices, and affects the voltage control in the electrical networks of the power supply organization. Since voltage management and compensation modes of reactive power are inseparable, they can be correctly determined only with the use of an integrated approach based on technical and economic criteria and taking into account technical requirements and local conditions. This article analyzes the mutual influence of voltage control and reactive power compensation modes in the electrical networks of industrial enterprises from the point of view of ensuring the quality of electricity and minimizing load power losses. The method and results of calculations (on the example of a specific industrial facility) for determining voltage deviations and losses in the electrical network as well as for selecting parameters for voltage control and reactive power compensation are presented. Due to the close relationship of these modes that affect all voltage levels, the effectiveness of measures cannot be ensured without the use of multifunctional devices for controlling the equipment of transformer substations.

scholarly journals ANALYSIS OF VOLTAGE NON-SINUSIDALITY IN POWER SUPPLY SYSTEMS WITH INDUCTION HEATING UNITS

2021 ◽  
pp. 122-133
Author(s):  
Dmitriy Yu. Rudi ◽  
Sergey V. Gorelov ◽  
Aleksandr I. Antonov ◽  
Mikhail G. Vishnyagov ◽  
Aleksandr A. Ruppel
Keyword(s):  
Electromagnetic Interference ◽  
High Performance ◽  
Low Frequency ◽  
Electrical Energy ◽  
Electrical Network ◽  
Electrical Networks ◽  
Harmonic Voltage ◽  
Harmonic Components ◽  
Quality Of Electrical Energy

The importance of the problem of improving the quality of electrical energy grew along with the development and widespread introduction of various high-performance technological installations in production, such as arc steel-making furnaces, welding installations, induction furnaces, etc. in accordance with the requirements of the standard GOST 30804.4.7–2013 and in accordance with the measurement program. A method for processing the research results obtained during the experiment is described. All power quality indicators are processed using computer programs created in the Labview graphical programming environment. The analysis of indicators of the quality of electrical energy to the requirements of GOST 32144-2013 was carried out, according to the results of which conductive low-frequency electromagnetic interference was detected in the 0.4 kV electrical network according to the coefficient of the n-th harmonic voltage components. The obtained values ​​of the indicators of the quality of electrical energy, characterizing the coefficient of the n-th harmonic components of the voltage, confirm the need to use technical means to reduce the influence of higher harmonics on electrical networks.

Quasi-static penetration behavior of fiber-reinforced polypropylene and acrylonitrile butadiene styrene matrix composites

2021 ◽  
pp. 089270572110079
Author(s):  
Ali İmran Ayten
Keyword(s):  
Glass Fiber ◽  
Energy Absorption ◽  
Matrix Material ◽  
Acrylonitrile Butadiene Styrene ◽  
Fiber Types ◽  
Matrix Composites ◽  
Aramid Fabric ◽  
Penetration Behavior ◽  
Fiber Fabric ◽  
Butadiene Styrene

The quasi-static punch shear behaviors of thermoplastic composites with different polymer matrices and fiber types were investigated. This study was also focused on how much energy absorption capability can be increased by low fiber fractions. Maleic anhydride grafted polypropylene (MA-g-PP) and acrylonitrile butadiene styrene (MA-g-ABS) were used as the matrix material. One layer of aramid, carbon and glass fiber plain weave fabrics was used as the reinforcement material. Quasi-static punch shear test (QS-PST) was applied to the samples to understand the penetration behavior of the samples. The damaged areas were investigated and related to force-displacement curves. The results showed that the neat form of MA-g-PP exhibited 158% more energy absorption than the neat form of MA-g-ABS. In the samples containing one layer of fabric, the highest improvement was observed in the aramid fabric-reinforced MA-g-ABS matrix composites. Aramid fabric increased the energy absorption at a rate of 142.3% in comparison to the neat MA-g-ABS, while carbon fiber fabric and glass fiber fabric increased it by 40% and 63.52%, respectively. Aramid fiber fabric provided no significant improvement in the energy absorption in the MA-g-PP matrix composites, while carbon and glass fiber fabrics contributed to energy absorption at a rate of 48% and 41%, respectively.

Solvent diffusion mechanism of PMMA/ acetone coated glass fiber fabric during curing process

2021 ◽  
pp. 152808372110362
Author(s):  
Zhenrong Zheng ◽  
Yuejiao Bi ◽  
Lihuan Tong ◽  
Yalan Liu
Keyword(s):  
Glass Fiber ◽  
Diffusion Mechanism ◽  
Coating Film ◽  
Curing Process ◽  
Curing Time ◽  
Solvent Concentration ◽  
Solvent Diffusion ◽  
Coated Glass ◽  
Drying Model ◽  
Fiber Fabric

Fabric it is not an impermeable substrate because of fiber porosity. To study the solvent diffusion mechanism of coated fabric in the curing process, the drying model of PMMA/acetone coated glass fiber fabric was established. This drying model was verified by confocal Raman spectroscopy. Finally, the impact of fabric structure, thickness and porosity on the solvent diffusion process in coated fabrics was studied by the model. It was shown that the predicted solvent concentrations by the model were consistent with the experimental values. This model can be used to quantitatively calculate the solvent concentration at any position and at any time inside the coating film during the drying process. Moreover, it can also predict the curing time and residual solvent concentration of the coating fabric required to reach drying equilibrium. Compared with coated 3/1 twill, 5/3 satin and 2/1 twill, the solvent diffusion of coated plain fabric was faster during curing. Under the same environmental conditions, the thinner the fabric was and the greater the porosity was, the shorter the curing time was. The fitting equations for fabric thickness, fabric porosity and drying time were obtained, which can provide a theoretical guidance for the preparation, performance research and drying conditions optimization of PMMA coated textile materials.

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