scholarly journals Schlieren Images of Negative Streamer and Leader Formations in CO2 and a CF3I-CO2 Electronegative Gas Mixture

2020 ◽  
Vol 10 (22) ◽  
pp. 8006
Author(s):  
Phillip Widger ◽  
Meirion Hills ◽  
Daniel Mitchard
Keyword(s):  
High Voltage ◽  
Energy System ◽  
Gas Mixtures ◽  
Electron Collision ◽  
Electrical Network ◽  
Lightning Strike ◽  
Gas Mixture ◽  
Electrical Networks ◽  
Gas Density ◽  
Sustainable Energy System

In electrical networks, SF6 gas is currently used to insulate high-voltage equipment, however, due to its high environmental impact, new alternatives such as CO2 and electronegative gas mixtures such as CF3I-CO2 are being trialled to replace SF6 and create a sustainable energy system. A high-voltage lightning impulse (1.2 μs/50 μs) was used to approximate the disturbance in a high-voltage electrical network caused by a lightning strike and helped to identify the likely streamer and leader formations in different gases insulating a piece of gas insulated switchgear. In this paper, the theoretical and practical aspects of electrical streamer and leader formations in pure CO2 and an electronegative gas mixture of CF3I-CO2 are examined using schlieren videography in small length rod-plane gas gaps between 20 and 50 mm in length. Schlieren allows the examination of gas density in streamer formations and for the differences in weakly attaching gases, such as CO2, and electronegative gas mixtures, such as CF3I-CO2, to be studied. The gas pressure is varied in order to examine the differences in streamer and leader formation as the gas density is varied and hence the probability of electron collision is varied.

scholarly journals Calculations, norming and reducing of electrical energy losses in city electrical networks

2019 ◽  
Vol 21 (3) ◽  
pp. 46-54
Author(s):  
A. V. Lykin ◽  
E. A. Utkin
Keyword(s):  
High Voltage ◽  
Power Transmission ◽  
Low Voltage ◽  
Demand Curve ◽  
Electrical Energy ◽  
Electrical Network ◽  
Energy Losses ◽  
Capital Investments ◽  
Electrical Networks

The article considers the feasibility of changing the structure of a distribution electrical network by transferring points of electricity transformation as close to consumers as possible. This approach is based on installation of pole-mounted transformer substations (PMTS) near consumer groups and changes the topology of the electrical network. At the same time, for groups of consumers, the configuration of sections of the low-voltage network, including service drops, changes. The efficiency of approaching transformer substations to consumers was estimated by the reduction in electrical energy losses due to the expansion of the high-voltage network. The calculation of electrical losses was carried out according to twenty-four hour consumer demand curve. To estimate the power losses in each section of the electrical network of high and low voltage, the calculated expressions were obtained. For the considered example, the electrical energy losses in the whole network with a modified topology is reduced by about two times, while in a high-voltage network with the same transmitted power, the losses are reduced to a practically insignificant level, and in installed PMTS transformers they increase mainly due to the rise in total idle losses. The payback period of additional capital investments in option with modified topology will be significantly greater if payback is assessed only by saving losses cost. Consequently, the determination of the feasibility of applying this approach should be carried out taking into account such factors as increasing the reliability of electricity supply, improving the quality of electricity, and increasing the power transmission capacity of the main part of electrical network.

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 Flexibility Assessment of Multi-Energy Residential and Commercial Buildings

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2704
Author(s):  
António Coelho ◽  
Filipe Soares ◽  
João Peças Lopes
Keyword(s):  
Large Scale ◽  
Residential Buildings ◽  
Renewable Energy Sources ◽  
Energy Systems ◽  
Energy System ◽  
Commercial Buildings ◽  
Electrical Network ◽  
Electrical Networks ◽  
Technical Problems ◽  
Integration Of Renewables

With the growing concern about decreasing CO 2 emissions, renewable energy sources are being vastly integrated in the energy systems worldwide. This will bring new challenges to the network operators, which will need to find sources of flexibility to cope with the variable-output nature of these technologies. Demand response and multi-energy systems are being widely studied and considered as a promising solution to mitigate possible problems that may occur in the energy systems due to the large-scale integration of renewables. In this work, an optimal model to manage the resources and loads within residential and commercial buildings was developed, considering consumers preferences, electrical network restrictions and CO 2 emissions. The flexibility that these buildings can provide was analyzed and quantified. Additionally, it was shown how this model can be used to solve technical problems in electrical networks, comparing the performance of two scenarios of flexibility provision: flexibility obtained only from electrical loads vs. flexibility obtained from multi-energy loads. It was proved that multi-energy systems bring more options of flexibility, as they can rely on non-electrical resources to supply the same energy needs and thus relieve the electrical network. It was also found that commercial buildings can offer more flexibility during the day, while residential buildings can offer more during the morning and evening. Nonetheless, Multi-Energy System (MES) buildings end up having higher CO 2 emissions due to a higher consumption of natural gas.

scholarly journals Pressurized CF3I-CO2 Gas Mixture under Lightning Impulse and its Solid By-Products

2017 ◽  
Vol 7 (6) ◽  
pp. 3088 ◽  
Author(s):  
M. S. Kamarudin ◽  
A. Haddad ◽  
B. C. Kok ◽  
N. A. M. Jamail
Keyword(s):  
High Voltage ◽  
Laboratory Tests ◽  
Gas Mixtures ◽  
Gas Pressure ◽  
Gas Mixture ◽  
Electrode Gap ◽  
Co2 Gas ◽  
Lightning Impulse ◽  
Edx Analyses ◽  
By Products

<span>This paper describes tests results on the CF<sub>3</sub>I-CO<sub>2</sub> gas mixtures as an alternative for SF<sub>6</sub> gas as to be used as insulating medium in high voltage applications. Pressurized CF<sub>3</sub>I-CO<sub>2</sub> gas mixtures are subject under standard lightning impulse voltages at both positive and negative polarities</span><span>. Under rod-plane configuration, the electrode gap length and gas pressure are varied accordingly. Upon completion of the laboratory tests, SEM and EDX analyses are carried out to assess the solid by-products. It was found that higher gas mixtures provide better insulation strength. In terms of weight, 50% of the solid by-product is found to be iodine.</span>

Study of the operation of an artificial neural network that works in the electric network in order to prevent emergency conditions.

2020 ◽  
Vol 14 (1) ◽  
pp. 48-54
Author(s):  
D. Ostrenko ◽  
Keyword(s):  
Neural Networks ◽  
Learning Algorithm ◽  
Electricity Consumption ◽  
Electrical Energy ◽  
Energy System ◽  
Electrical Networks ◽  
Electric Networks ◽  
Electric Network ◽  
Time Dynamics ◽  
Emergency Situations

Emergency modes in electrical networks, arising for various reasons, lead to a break in the transmission of electrical energy on the way from the generating facility to the consumer. In most cases, such time breaks are unacceptable (the degree depends on the class of the consumer). Therefore, an effective solution is to both deal with the consequences, use emergency input of the reserve, and prevent these emergency situations by predicting events in the electric network. After analyzing the source [1], it was concluded that there are several methods for performing the forecast of emergency situations in electric networks. It can be: technical analysis, operational data processing (or online analytical processing), nonlinear regression methods. However, it is neural networks that have received the greatest application for solving these tasks. In this paper, we analyze existing neural networks used to predict processes in electrical systems, analyze the learning algorithm, and propose a new method for using neural networks to predict in electrical networks. Prognostication in electrical engineering plays a key role in shaping the balance of electricity in the grid, influencing the choice of mode parameters and estimated electrical loads. The balance of generation of electricity is the basis of technological stability of the energy system, its violation affects the quality of electricity (there are frequency and voltage jumps in the network), which reduces the efficiency of the equipment. Also, the correct forecast allows to ensure the optimal load distribution between the objects of the grid. According to the experience of [2], different methods are usually used for forecasting electricity consumption and building customer profiles, usually based on the analysis of the time dynamics of electricity consumption and its factors, the identification of statistical relationships between features and the construction of models.

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