scholarly journals Influence of supply voltage and frequency variations on the electrical equipment and power consumption in LV and MV distribution networks

Energetika ◽  
2020 ◽  
Vol 65 (4) ◽  
Author(s):  
Illia Diahovchenko ◽  
Nataliia Sushchenko ◽  
Anton Shulumei ◽  
Oleksandr Strokin
Keyword(s):  
Power Systems ◽  
Low Voltage ◽  
Supply Voltage ◽  
Electric Energy ◽  
Stochastic Theory ◽  
Electrical Equipment ◽  
Distribution Networks ◽  
Quality Parameters ◽  
Electric Energy Consumption ◽  
Frequency Variations

This paper is focused on the analysis of supply voltage and frequency quality in low voltage and medium voltage distribution power systems. The influence of supply voltage and frequency variations, within the limits defined in the valid standards, on the power network’s parameters has been evaluated using the stochastic theory and the statistical analysis methods. The circuit of RLC-load was considered for numerical evaluation. The probability distribution of supply voltage and frequency was defined and the suggestions on optimum voltage and frequency quality parameters regarding electric energy consumption, power losses and electrical equipment lifespan were given.

Analysis of operation of Oblkommunergo electric networks of Irkutsk Region

2021 ◽  
Vol 14 (3) ◽  
pp. 100-110
Author(s):  
I. V. Naumov
Keyword(s):  
Low Voltage ◽  
Average Duration ◽  
Electric Energy ◽  
Distribution Networks ◽  
Operational Reliability ◽  
Electrical Networks ◽  
Electric Networks ◽  
Public Media ◽  
Irkutsk Region ◽  
Graphic Editor

Analysis has been performed of the operation of electric distribution networks of ten branches of Oblkommunenergo (OKE) of Irkutsk Region [1]. Based on the data on the operation of these networks published in public media, algorithms and computer programs for the Matlab graphic editor are compiled, which are used for plotting time diagrams that characterize the operation of the electrical networks under consideration. The balance changes are shown in the transmission of electric energy into the OKE networks and from the OKE networks directly to consumers (high, medium and low voltage networks). The number of failures, the power supply interruption time and the amount of electricity undersupplied in each month of the year for each of the branches are considered. The months of the year are determined, in which the greatest and least damage occurs to the electrical networks of the OKE branches. Data are presented on the dynamics of annual wear of electric networks, planned activities and their annual implementation. The level of reliability is considered according to the established indicators of the average duration of interruptions in the transmission of electric energy in each calculated regulation period. It is shown that the combination of the main causes of failures largely depends on the natural-climatic and terrain specifics of the regions through which the routes of electric networks pass. As an example, data on the causes of failure in the electrical networks of one of the OKE branches are considered. The most and least damaged electrical networks of the considered OKE branches have been established. In conclusion, findings are formulated and recommendations are presented on minimizing outages based on the main types of failure causes for the purpose of increasing the operational reliability of the electrical networks under consideration.

scholarly journals QUALITY OPTIMIZATION OF THE MACHINED SURFACE IN TERMS OF ELECTRIC ENERGY CONSUMPTION IN THE WEDM PROCESS

2021 ◽  
Vol 2021 (2) ◽  
pp. 4400-4407
Author(s):  
LUBOSLAV STRAKA ◽  
◽  
PATRIK KUCHTA ◽  
Keyword(s):  
Energy Consumption ◽  
Production Process ◽  
Electric Energy ◽  
Quality Parameters ◽  
Machining Process ◽  
Discharge Energy ◽  
Machined Surface ◽  
Electric Energy Consumption ◽  
Wedm Process

Current engineering production is characterized by ever-increasing requirements for the final quality of products. But high fabrication productivity is required in many cases as well. Another advantage is, of course, a beneficial economic efficiency of the production process. However, despite the advanced technical level of production and extensive knowledge in the field of electro-erosive machining, in many cases, the overall efficiency of the production process is based on the skills of operators. Besides, insufficiently experienced production operators sometimes still use the trial and error system, even today. A comprehensive set of information for selecting optimal conditions of the electric discharge machining process with the possibility of practical application in real conditions of practice is currently non-existent. The paper therefore describes the experimental measurements performed in order to optimize the quality of the machined surface with respect to electric energy consumption in the WEDM process. In contrast to current approaches, the solution of the issue relied on determining the relationship between the performance parameters of the process and its controllable output quality parameters so that they would be applicable to the conditions of real practice. It was found that with the reduction of discharge energy through individual WEDM operations, the quality indicators in terms of roughness parameters improve. However, on the other hand, reducing the discharge energy leads to a significant increase in the total electric energy consumption. Therefore, the aim of the performed optimization was to look for a suitable type of WEDM operation, in which a favourable value of the roughness of the eroded surface is achieved while maintaining favourable electric energy consumption.

scholarly journals Methodology for assessing the power of the primary source of the system of autonomous electrical supply with account of the predicted load graphics

2019 ◽  
Vol 64 (2) ◽  
pp. 205-214
Author(s):  
D. V. Karkotski ◽  
A. N. Malashin ◽  
S. A. Chumakov ◽  
Y. G. Koval
Keyword(s):  
Supply Voltage ◽  
Electric Energy ◽  
Operation Time ◽  
Primary Source ◽  
Electrical Energy ◽  
Quality Parameters ◽  
Limited Information ◽  
Autonomous Operation ◽  
Current Consumption ◽  
The Impact

When developing new or upgrading existing energy-intensive mobile objects (MO), the main way to ensure the quality parameters of the supply voltage is no worse than in the state grid, overestimation of the primary source (PS) power is 1.5–2 times relative to the maximum power of all electrical energy consumers (EEC) software.The consequence of the existing approach to determine the power of PS are: overestimation of the mass and dimensions of the autonomous power supply system (APSS) by 30–70 %, which significantly reduces speed characteristics, cross-country performance and battery autonomy of MO, as well as worsen the economics of the APSS; the workload of the PS APSS is not more than 35–55 % of the nominal capacity, which leads to a reduction in their service lives.Thus, it is impossible to take into account the peculiarities of the actual current consumption of individual EEC and the impact of their joint operation on specific PS APSS, which leads to additional financial costs and an increase in development time, as well as to the risk of failure during the testing of both the APSS and the equipment connected to it.The proposed approach for estimating the PS power of electric energy in APSS MO allows determining the full power of the EEC in terms of limited information about the EEC taking into account the nature of the load graph, as well as the magnitude and form of current consumption. As a result of analytical calculations according to the above methodology, the PS power can be reduced by 13–45 %, depending on the nature of the load, while maintaining the quality indicators of the supply voltage within acceptable limits.The considered methods for determining the power of the PS APSS will make it possible to determine the limitations for solving the problem of structural-parametric synthesis of the APSS and the algorithm for determining the power of the PS when developing a new or upgrading the existing APSS MO. This will reduce the weight and size parameters of the APSS, thereby increasing the speed characteristics, maneuverability and software permeability of MO, as well as the autonomous operation time and efficiency of the APSS operation.

scholarly journals Investigation on Using Low Voltage Automatic Regulation to Minimize the Impacts of Charging Plug-in Electric Vehicles in Distribution Systems

2021 ◽  
Vol 19 ◽  
pp. 85-90
Author(s):  
Priscila Costa Nascimento ◽  
◽  
Michel Girotto de Oliveira ◽  
José Carlos M. Vieira
Keyword(s):  
Steady State ◽  
Electric Vehicles ◽  
Distribution System ◽  
Distribution Systems ◽  
Low Voltage ◽  
Electric Energy ◽  
Distribution Networks ◽  
Voltage Regulation ◽  
Automatic Regulation ◽  
Electric Energy Storage

The growth of micro and mini distributed generation and, more recently, the use of electric energy storage systems and the incentives for electric mobility are important examples of the transformations that distribution networks have been going through. In this context, this paper firstly presents the impacts of uncoordinated plug-in electric vehicles (PEVs) charging in a real Brazilian distribution system. Four scenarios were elaborated with different PEVs penetration levels and the results show increased voltage unbalance, system losses, and violations of the steady-state voltage limits, even in the presence of an automatic voltage regulator installed in the medium voltage network. Then, as the main contribution, the potential usage of automatic voltage regulation at the low voltage network was investigated to minimize the negative impacts of uncontrolled PEV charging on distribution system steady-state operation. It is important to highlight that this is not a common practice of utilities in Brazil. The obtained results showed that regulating the voltage at the low voltage side could be an effective solution to keep the voltages within statutory limits.

scholarly journals Integration of Electric Vehicles in Low-Voltage Distribution Networks Considering Voltage Management

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4125
Author(s):  
Miguel Carrión ◽  
Rafael Zárate-Miñano ◽  
Ruth Domínguez
Keyword(s):  
Power Systems ◽  
Electric Vehicles ◽  
Power Flow ◽  
Optimal Power Flow ◽  
Low Voltage ◽  
Distribution Network ◽  
Planning Horizon ◽  
Distribution Networks ◽  
Mixed Integer ◽  
Distribution Grid

The expected growth of the number of electric vehicles can be challenging for planning and operating power systems. In this sense, distribution networks are considered the Achilles’ heel of the process of adapting current power systems for a high presence of electric vehicles. This paper aims at deciding the maximum number of three-phase high-power charging points that can be installed in a low-voltage residential distribution grid. In order to increase the number of installed charging points, a mixed-integer formulation is proposed to model the provision of decentralized voltage support by electric vehicle chargers. This formulation is afterwards integrated into a modified AC optimal power flow formulation to characterize the steady-state operation of the distribution network during a given planning horizon. The performance of the proposed formulations have been tested in a case study based on the distribution network of La Graciosa island in Spain.

scholarly journals Calculating Operational Patterns for Electric Vehicle Charging on a Real Distribution Network Based on Renewables’ Production

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2400 ◽  
Author(s):  
Stavros Lazarou ◽  
Vasiliki Vita ◽  
Christos Christodoulou ◽  
Lambros Ekonomou
Keyword(s):  
Power Systems ◽  
Electric Vehicle ◽  
Electric Vehicles ◽  
High Performance ◽  
Electric Energy ◽  
Distribution Networks ◽  
Electric Vehicle Charging ◽  
Adequate Knowledge ◽  
Real Distribution ◽  
Vehicle Charging

The connection of electric vehicles to distribution networks has been an emerging issue of paramount importance for power systems. On one hand, it provides new opportunities for climate change mitigation, if electric energy used for charging is produced from zero emission sources. On the other hand, it stresses networks that are now required to accommodate, in addition to the loads and production from distributed generation they are initially designed for, loads from electric vehicles charging. In order to achieve maximum use of the grid without substantially affecting its performance, these issues have to be addressed in a coordinated manner, which requires adequate knowledge of the system under consideration. It is advantageous that electric vehicle charging can be controlled to a certain degree. This research provides better understanding of real distribution networks’ operation, proposing specific operational points through minimizing electric vehicle charging effects. The probabilistic Monte Carlo method on high performance computers is used for the calculations.

scholarly journals Substantiation of the choice of the replacement scheme of line for mathematical modeling of 20 kV power supplies.

2021 ◽  
Vol 24 (1) ◽  
pp. 69-72
Author(s):  
SKRYPNYK S. ◽  
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Power Supply ◽  
Electrical Equipment ◽  
Distribution Networks ◽  
Power Line ◽  
Power Lines ◽  
Electrical Networks ◽  
Overhead Lines ◽  
Replacement Scheme

In the current global economic crisis and acute shortage of energy resources, increasing importance is attached to energy saving measures, economical and careful consumption of raw materials, materials, electricity and heat, environmental safety of industrial production. During the reconstruction of existing power supply systems of industrial enterprises, modern progressive solutions should be considered and implemented, morally and physically obsolete electrical equipment should be replaced, namely the introduction of new electrical equipment for transition from 6/10 kV to 20 kV in Ukrainian power systems. It is also necessary to pay attention to the improvement of power supply circuits and distribution networks, the implementation of complex automation of complex technological processes, rational compensation of reactive power at all levels of power supply systems. In the power system, the main transport link is the power line. Power lines (transmission lines) are long conductors suspended at a safe distance from the ground overhead lines (overhead lines) or cable lines (overhead lines) in which conductors are insulated from each other and from the environment and protected by insulation and armor electricity. Power lines are the most massive elements of the power supply system, they connect the individual nodes of its circuit. Longitudinal and transverse parameters are distinguished in alternative schemes. The load current flows through the longitudinal parameters, voltage is applied to the transverse ones. The replacement circuit of the electrical network consists of replacement circuits of the following elements: power lines, transformers, reactors, capacitors, loads, power sources. Calculating the steady-state modes of power systems, the substitution schemes of the elements are given in a single-line design, because the parameters of all phases are symmetrical. In local and local electrical networks with a relatively short length and low rated voltage, the conduction currents are small compared to load currents. Therefore, in typical electrical calculations of these networks, the capacitive conductivity of the lines is not taken into account. However, for these networks, the accounting of capacitive conductivities is necessary when considering some modes, the existence of which in itself is due only to the presence of capacitive conductivities. For example, the mode of single-phase ground fault in a network with isolated or compensated neutral or analysis of the modes of operation of neutrals of electrical networks of different voltage classes cannot be performed without taking into account the capacitive conductivity of these networks. When switching the power system of Ukraine to the nominal voltage of 20 kV, it should be taken into account that the transmission line will be replaced in the sections of both the overhead power line and cable power line, namely 35, 10, 6 kV. The replacement scheme must describe all the characteristics and properties of the elements of cable and overhead lines in accordance with real conditions. Thus, it is not expedient to use simplified substitution circuits that neglect energy parameters and properties of conductors to study the parameters of transmission lines. The use of a complete "P" -shaped scheme for the analysis of the parameters of transmission lines and transmission lines for a voltage of 20 kV is the basis of mathematical modeling of the transmission system in the distribution networks of our country.

scholarly journals A Review of Low-Voltage Renewable Microgrids: Generation Forecasting and Demand-Side Management Strategies

Electronics ◽  
2021 ◽  
Vol 10 (17) ◽  
pp. 2093
Author(s):  
Miguel Aybar-Mejía ◽  
Junior Villanueva ◽  
Deyslen Mariano-Hernández ◽  
Félix Santos ◽  
Angel Molina-Garcia
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
Distributed Generation ◽  
Low Voltage ◽  
Renewable Energy Sources ◽  
Demand Management ◽  
Management Strategies ◽  
Renewable Resource ◽  
Distribution Networks ◽  
Management Systems

It is expected that distribution power systems will soon be able to connect a variety of microgrids from residential, commercial, and industrial users, and thus integrate a variety of  distributed generation technologies, mainly renewable energy sources to supply their demands. Indeed, some authors affirm that distribution networks will propose significant changes as a consequence of this massive integration of microgrids at the distribution level. Under this scenario, the control of distributed generation inverters, demand management systems, renewable resource forecasting, and demand predictions will allow better integration of such microgrid clusters to decongest power systems. This paper presents a review of  microgrids connected at distribution networks and the solutions that facilitate their integration into such distribution network level, such as demand management systems, renewable resource forecasting, and demand predictions. Recent contributions focused on the application of microgrids in Low-Voltage distribution networks are also analyzed and reviewed in detail. In addition, this paper provides a critical review of the most relevant challenges currently facing electrical distribution networks, with an explicit focus on the massive interconnection of electrical microgrids and the future with relevant renewable energy source integration.

scholarly journals An Analysis of Electromagnetic Disturbances from an Electric Vehicle Charging Station

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 244
Author(s):  
Paweł Mazurek ◽  
Aleksander Chudy
Keyword(s):  
Power Quality ◽  
Electric Energy ◽  
Distribution Networks ◽  
Quality Parameters ◽  
Voltage Profile ◽  
Current Harmonics ◽  
Charging Station ◽  
Charging Stations ◽  
Electromagnetic Disturbances ◽  
Ev Charging

The electric vehicles (EVs) could potentially have a significant impact on power quality parameters and distribution networks as they are non-linear loads and their charging might result in tremendous power demand. When connected to the utility grid, a large number of EV charging stations from different manufacturers might create significant harmonic current emissions, impact the voltage profile, and eventually affect the power quality. Nevertheless, practical examples of disturbances from charging stations have not been made public. This paper aims to clarify the characteristics of conductive disturbances and levels of current harmonics generated by charging station and their severity on the quality of electric energy. The analysis was based on tests of a prototype station of an EV charging station integrated with a LED street light. The tests concern the determination of current harmonics and the values of conductive electromagnetic disturbances in the 150 kHz–30 MHz range. The test results of the prototype charger with observed exceedances of current harmonics (25th–39th range) and conducted interference exceedances are comprehensively described. After applying filtering circuits to the final version of the station, retesting in an accredited laboratory showed qualitative compliance.

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