scholarly journals THE ABILITY OF MODERN TECHNOLOGIES TO INFLUENCE THE NEUTRAL MODE OF ELECTRIC GRIDS

2021 ◽  
pp. 103-112
Author(s):  
Georgi M. Mikheev ◽  
Ayrat G. Ziganshin
Keyword(s):  
Transmission Lines ◽  
Power Transformer ◽  
Electrical Equipment ◽  
Economic Feasibility ◽  
Neutral Point ◽  
Electrical Safety ◽  
Neutral System ◽  
Electric Networks ◽  
Microprocessor Technology ◽  
Arc Suppression Reactors

In this article, we consider the modes of neutrals of 0,38 to 750 kV networks. In any network with different voltage classes, the neutral point of a power transformer winding can operate both in isolated and deaf earthed mode. However, the choice of this mode depends on economic feasibility. The paper presents arguments and advantages of application of system with isolated and compensated neutral of networks with voltage classes 6–35 kV. For networks of these voltage classes various options of connecting arc suppression reactors with step and smooth regulation, as well as low and high impedance resistors in the neutral point of neutralizing transformer or zero sequence filter are considered. On the example of operation of electric networks of the Republic of Chuvashia for many decades it is emphasized that compensation of capacitive currents with arc suppression reactors is an effective and reliable way to protect not only substation electrical equipment from overvoltage, but also to ensure electrical safety of people and animals, as well as reinforced concrete towers from destruction. It is noted that the 6–35 kV networks in the future can be made with deaf earthed neutral. However, this will be possible under the condition that self-supporting insulated wires will be installed on overhead transmission lines instead of bare wires, and cross-linked polyethylene cables will be used on cable lines. It is emphasized that the introduction of work under voltage in 6-35 kV networks and digitalization of substations with the widespread introduction of microprocessor technology will accelerate the transition from a system with insulated (or compensated) neutral to a deaf earthed system. Nevertheless, the decision to switch from the insulated neutral system to a deaf earthed system will remain the prerogative of the design organization based on the specifics of the electrical equipment and the sphere of industrial activity.

scholarly journals Evaluating through mathematical modelling the power equipment busbars electrodynamic strength under sudden short-circuit conditions

2018 ◽  
Vol 210 ◽  
pp. 02004
Author(s):  
Cornelia A. Bulucea ◽  
Constantin Brindusa ◽  
Doru A. Nicola ◽  
Nikos E. Mastorakis ◽  
Carmen A. Bulucea ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Power Transmission ◽  
Power Transformer ◽  
Short Circuit ◽  
Simulation Models ◽  
Electrical Equipment ◽  
Power Transmission Lines ◽  
Electric Circuits ◽  
Mechanical Deformations ◽  
Electrodynamic Forces

The electrodynamic strength, as forces acting between the current-carrying electric circuits are exerted as long as the currents exist, and have the tendency of deformation and displacement of the circuits. In short-circuit regimes the strength in electrical equipment becomes severe. For instance, short-circuits highly affect power transformers connected to power transmission lines. The effects are also strong because of mechanical deformations occurring in the power transformer connection part. In line with this idea, in this paper it is made an analytical study upon the a.c. single-phase and a.c. three-phase electric circuits, taking into account the current instantaneous maximum value. The paper also entails numerical simulations of electrodynamic strength in power transformer busbars under short-circuit conditions. MATLAB software, with its specific extensions, enable simulation models to generate the charts of the electrodynamic forces in the power transformer connection bars.

Study of power transformer loading in rural power supply systems

2021 ◽  
Vol 13 (4) ◽  
pp. 282-289
Author(s):  
I. V. Naumov ◽  
D. N. Karamov ◽  
A. N. Tretyakov ◽  
M. A. Yakupova ◽  
E. S. Fedorinovа
Keyword(s):  
Energy Efficiency ◽  
Power Supply ◽  
Rural Areas ◽  
Power Transformer ◽  
Electric Energy ◽  
Power Transformers ◽  
Electric Networks ◽  
Load Factors ◽  
Optimal Load ◽  
Supply Systems

The purpose of this study is to study the effect of loading power transformers (PT) in their continuous use on their energy efficiency on a real-life example of existing rural electric networks. It is noted that the vast majority of PT in rural areas have a very low load factor, which leads to an increase in specific losses of electric energy when this is transmitted to various consumers. It is planned to optimize the existing synchronized power supply systems in rural areas by creating new power supply projects in such a way as to integrate existing power sources and ensure the most efficient loading of power transformers for the subsequent transfer of these systems to isolated ones that receive power from distributed generation facilities. As an example, we use data from an electric grid company on loading power transformers in one of the districts of the Irkutsk region. Issues related to the determination of electric energy losses in rural PT at different numerical values of their load factors are considered. A computing device was developed using modern programming tools in the MATLAB system, which has been used to calculate and plot the dependence of power losses in transformers of various capacities on the actual and recommended load factors, as well as the dependence of specific losses during the transit of 1 kVA of power through a power transformer at the actual, recommended and optimal load factors. The analysis of specific losses of electric energy at the actual, recommended and optimal load factors of PT is made. Based on the analysis, the intervals of optimal load factors for different rated power of PT of rural distribution electric networks are proposed. It is noted that to increase the energy efficiency of PT, it is necessary to reduce idling losses by increasing the load of these transformers, which can be achieved by reducing the number of transformers while changing the configuration of 0.38 kV distribution networks.

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.

Relay protection and automation of electric power systems

2021 ◽  
Author(s):  
Sergey Goremykin
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Relay Protection ◽  
Electrical Equipment ◽  
Electric Power Systems ◽  
Federal State ◽  
Advantages And Disadvantages

The textbook describes the main issues of the theory of relay protection and automation of electric power systems. The structure and functional purpose of protection devices and automation of power transmission lines of various configurations, synchronous generators, power transformers, electric motors and individual electrical installations are considered. For each of the types of protection of the above objects, the structure, the principle of operation, the order of selection of settings are given, the advantages and disadvantages are evaluated, indicating the scope of application. The manual includes material on complete devices based on semiconductor and microprocessor element bases. The progressive use of such devices (protection of the third and fourth generations) is appropriate and effective due to their significant advantages. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for students in the areas of training 13.03.02 "Electric power and electrical engineering" (profile "Power supply", discipline "Relay protection and automation of electric power systems") and 35.03.06 "Agroengineering" (profile "Power supply and electrical equipment of agricultural enterprises", discipline "Relay protection of electrical equipment of agricultural objects"), as well as for graduate students and specialists engaged in the field of electrification and automation of industrial and agrotechnical objects.

Protective Devices Maintenance and the Potential Impact on Arc Flash Energy

2012 ◽  
Author(s):  
Dennis K. Neitzel
Keyword(s):  
Electrical Equipment ◽  
Electrical Safety ◽  
Protective Devices ◽  
Potential Impact ◽  
Arc Flash ◽  
Safety Considerations ◽  
Insight Into

This paper provides insight into the electrical safety considerations, specifically as it relates to maintenance of electrical overcurrent protective devices, and the potential impact on the arc flash energy for shipboard electrical equipment and systems application. It provides valuable information for the electricians, technicians, and engineers who operate and maintain the electrical equipment.

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.

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...

Operation, diagnosis and repair of electrical

2020 ◽  
Author(s):  
Vladimir Polischuk
Keyword(s):  
Undergraduate Students ◽  
Transmission Lines ◽  
Electrical Engineering ◽  
Electrical Equipment ◽  
Electrical Machines ◽  
Technical Maintenance ◽  
Maintenance Service

In the textbook fundamentals of the theory of diagnostics of electrical equipment, organization of technical maintenance, service and repair. The methods of organization of maintenance of electrical machines, transformers, transmission lines and cables. Designed for undergraduate students enrolled in the specialty "power and electrical engineering".

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