scholarly journals Current Quality: Assessment and Standardization Aspects

2020 ◽  
Vol 20 (4) ◽  
pp. 23-35
Keyword(s):  
Power Quality ◽  
Quality Indicators ◽  
Electromagnetic Compatibility ◽  
Urban Infrastructure ◽  
Field Measurements ◽  
Harmonic Current ◽  
Ongoing Research ◽  
The Subject ◽  
Harmonic Components ◽  
Waveform Distortions

Power quality issues concern absolutely all spheres of human activity, from household to economy and transportation. Standardization, monitoring, management, and coordination to ensure electromagnetic compatibility in the power supply system are the subject of constantly ongoing research in most countries. In order to attract attention to issues of the harmonic current, this study focused on the harmonic current distortions observed on the level of urban electricity users. The paper considers the aspects of consolidating terminology and structure of power quality indicators. We carefully reviewed the current and voltage waveform distortions and related harmonic components. We also summed up the power quality indicators currently used around the world as a flowchart. Based on the results of measurements of quality indicators at the existing urban infrastructure facilities, a comparative analysis with the IEEE 519-2014 standard requirements was performed. As a result of the field measurements analysis, an unsatisfactory situation in terms of harmonic current distortions was revealed; the most probable causes and consequences of poor current quality are described.

scholarly journals Electric supply of high-energy consumers of Murmansk region

2020 ◽  
Vol 11 (7-2020) ◽  
pp. 58-66
Author(s):  
Vera V. Yaroshevich ◽  
◽  
Aleksei S. Karpov ◽  
Galina P. Fastiy ◽  
Sergei V. Smotrov ◽  
...  
Keyword(s):  
Electric Power ◽  
Power Quality ◽  
Quality Indicators ◽  
Electromagnetic Compatibility ◽  
High Energy ◽  
Industrial Enterprises ◽  
Murmansk Region ◽  
Electric Power Quality ◽  
Non Linear ◽  
Electric Supply

The systematization and analysis of the results of monitoring registrations of electric power quality indicators (PQS) on substation buses feeding large industrial enterprises of the Murmansk region was carried out. The example of existing substations shows the problems of high-energy facilities that have consumers with non-linear parameters. The problems of electromagnetic compatibility of industrial consumers with the mains have been identified. The need for research to identify the causes of non-compliance is proved. A number of the most common and effective measures to limit the distortion of the SCE are proposed.

INVESTIGATION OF CHARACTERISTICS OF THE GRAIN RECEIVING FROM RAILWAY TO THE GRAIN TRANSSHIPMENT TERMINAL

2020 ◽  
Vol 20 (2) ◽  
pp. 7-13
Author(s):  
G. Stankevych ◽  
L. Dmytrenko ◽  
A. Kats ◽  
V. Shpak
Keyword(s):  
Quality Indicators ◽  
Grain Quality ◽  
Total Duration ◽  
Railway Transport ◽  
Oil Crops ◽  
The Future ◽  
Leading Position ◽  
Standard Values ◽  
The Subject ◽  
Sown Area

In the future, in Ukraine it is planned to increase the sown area for cereals, legumes and oilseeds, to increase the gross grain harvest to 80 million tons, and its export abroad was increased twice. Intensive construction in the southern ports of Ukraine of grain transshipment terminals with large metal silos will solve the problem of increasing grain export in the future. At these powerful terminals, the bulk of the grain comes mainly by rail, and is shipped to water. The aim of the work was to study the characteristics of the grain receiving from railway transport to the grain transshipment terminal of LLC “Ukrelevatorprom” in order to improve its works efficiency. The object of the study was the development of technology of grain receiving at the grain transshipment terminal; the subject of research is cereals, legume sand oil crops, as well as data from daily volumes of receiving and dispensing operations at the grain transshipment terminal of LLC “Ukrelevatorprom” for 2015-2016. The studies were carried out on the basis of processing data from the consignment notes for 2015-2016, according to which there was a summed amount of grain (net) daily transported by the railway. Further processing of the obtained data was carried out by a combined graphoanalytical method, for which, on the basis of tabular values for each studied year, the corresponding histograms and graphs were built and the necessary indicators were determined. Analysis of the structure of grain crops supplied by railway to LLC “Ukrelevatorprom” in 2015 and 2016 and their ratio showed that the main share was occupied by cereal crops (78.0 % and 73.1 % respectively), which were mainly represented by corn, share which was significantly dominated by other crops (wheat of various classes and barley) and amounted to 45.8 % and 44.5 %, respectively, which can be explained by its high demand in the international grain market, in which Ukraine occupies a leading position. Oilseeds (rapeseed) were taken in accordance with 19.1 % and 14.9 %, and legumes (soybeans) — 2.9 % and 12.0 %. An analysis of the timing of the unloading of grain wagons (hopper cars) showed that the total duration of this process, depending on the crops, averages 37...59 minutes. The longest steps for unloading wagons are to determine the grain quality indicators, especially rapeseed, and to spill grain from the wagons, therefore, to reduce their duration, it is necessary to form feeds of wagons with grain batches of the same quality and use more modern express analyzers to determine grain quality indicators, which will increase the productivity of the grain receiving line from the railway. According to the research results, the enterprise has the potential to increase by about 30 % the volume of grain intake. It was established that the periods of the grain receipt at the enterprise in 2015-2016 amounted to 349 and 353 days, respectively, the actual coefficients of the daily irregularity Kdaily for the grain receipt from the railway in these years are equal to 1.47 and 1.52, and the monthly irregularity Kmonth, respectively 1.33 and 1.21, does not exceed the standard values Kdaily = 2.5 and Kmonth= 2.0. This made it possible to clarify the database from the actual characteristics of the process of grain receiving by railway and can be used in design and verification calculations of equipment in technological lines for receiving grain from railway transport, and will contribute to increasing the efficiency of grain transshipment terminals. 

OS IMPACTOS AMBIENTAIS ORIUNDOS DA IMPLANTAÇÃO DA VIA PAISAGÍSTICA AS MARGENS DO RIO MARANGUAPINHO NO BAIRRO CANINDEZINHO, FORTALEZA – CE

2019 ◽  
Vol 21 (2) ◽  
pp. 1374-1386
Author(s):  
Daniel Paulo Braga ◽  
Gislania de Meneses Silva ◽  
Tulio Viana Bandeira ◽  
Maria Lucia Brito da Cruz
Keyword(s):  
Environmental Impact ◽  
Urban Space ◽  
Satellite Images ◽  
Spatial Organization ◽  
Urban Infrastructure ◽  
Public Agencies ◽  
Protection Area ◽  
The Subject ◽  
Del Rio ◽  
Digital Or

O referido trabalho busca fazer uma análise dos impactos ambientais oriundos da construção da via paisagística às margens do Rio Maranguapinho no bairro Canindezinho, ressaltando as transformações geradas pela sua implantação e a modificação do espaço urbano e das formas de ocupação da planície fluvial do rio neste trecho. Para a obtenção de resultados, foi realizado pesquisas bibliográficas e visitas em órgãos públicos para levantamento e obtenção de material digital ou impresso acerca da temática abordada. Efetuou-se a análise de imagens de satélite dos anos de 2010 e 2016 em caráter de comparação das temporalidades quanto as ocupações na Área de Proteção Permanente – APP. Também foram realizadas visitas de campo em pontos do bairro para verificação dos impactos e melhor compreender a realidade do objeto em estudo. Logo, os resultados demonstram que as intervenções realizadas pela via paisagística agregaram outros equipamentos urbanos de infraestrutura e organização espacial, tais como barragens, praças e conjuntos habitacionais, incluindo a qualificação das margens para a recuperação das APPs de aproximadamente 50 metros ao longo do rio, contudo, foram identificados problemas quanto a remoção dos moradores e a utilização das áreas desapropriadas para a acumulação de resíduos sólidos.Palavras-chave: Área de Preservação Permanente. Recursos Hídricos. Impacto Ambiental. ABSTRACTThis work seeks to analyze the environmental impacts of the construction of the landscaped road on the banks of the Maranguapinho River in the Canindezinho neighborhood, highlighting the transformations generated by its implantation and the modification of the urban space and the forms of occupation of the fluvial plain of the river in this section . In order to obtain results, bibliographical researches and visits were made to public agencies to collect and obtain digital or printed material about the subject matter. The analysis of satellite images of the years 2010 and 2016 was carried out in a comparison of temporalities and occupations in the Permanent Protection Area (APP). Field visits were also carried out at points in the neighborhood to verify impacts and better understand the reality of the object being studied. Therefore, the results show that the landscape interventions added other urban infrastructure and spatial organization equipment, such as dams, squares and housing complexes, including the qualification of the margins for the recovery of PPAs of approximately 50 meters along the river, however, problems were identified regarding the removal of the residents and the use of the expropriated areas for solid waste accumulation.Keywords: Permanent Preservation Area. Water resources. Environmental impact. RESUMENEste trabajo busca analizar los impactos ambientales derivados de la construcción de la carretera ajardinada a orillas del río Maranguapinho en el barrio de Canindezinho, destacando las transformaciones generadas por su implementación y la modificación del espacio urbano y las formas de ocupación de la llanura del río en este tramo. . Para obtener resultados, se llevaron a cabo investigaciones bibliográficas y visitas a agencias públicas para recopilar y obtener material digital o impreso sobre el tema. Se analizaron imágenes satelitales de 2010 y 2016 para comparar las temporalidades con respecto a las ocupaciones en el Área de Protección Permanente - APP. También se realizaron visitas de campo en puntos del vecindario para verificar los impactos y comprender mejor la realidad del objeto en estudio. Por lo tanto, los resultados muestran que las intervenciones paisajísticas han agregado otra infraestructura urbana y equipo de organización espacial, como presas, plazas y urbanizaciones, incluida la calificación de márgenes para la recuperación de APP de aproximadamente 50 metros a lo largo del río, sin embargo, se identificaron problemas con respecto a la remoción de residentes y el uso de áreas expropiadas para la acumulación de desechos sólidos.Palabras clave: Área de Preservación Permanente. Recursos hídricos. Impacto ambiental.

scholarly journals Improving Power Quality by a Four-Wire Shunt Active Power Filter: A Case Study

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1951
Author(s):  
Mihaela Popescu ◽  
Alexandru Bitoleanu ◽  
Mihaita Linca ◽  
Constantin Vlad Suru
Keyword(s):  
Power Quality ◽  
Quality Indicators ◽  
Reactive Power ◽  
Control Method ◽  
Active Power Filter ◽  
Active Power ◽  
Current Control ◽  
Shunt Active Power Filter ◽  
Power Filter ◽  
Unbalanced Load

This paper presents the use of a three-phase four-wire shunt active power filter to improve the power quality in the Department of Industrial Electronics of a large enterprise from Romania. The specificity is given by the predominant existence of single-phase consumers (such as personal computers, printers, lighting and AC equipment). In order to identify the power quality indicators and ways to improve them, an A-class analyzer was used to record the electrical quantities and energy parameters in the point of common coupling (PCC) with the nonlinear loads for 27 h. The analysis shows that, in order to improve the power quality in PCC, three goals must be achieved: the compensation of the distortion power, the compensation of the reactive power and the compensation of the load unbalance. By using the conceived three-leg shunt active power filter, controlled through the indirect current control method in an original variant, the power quality at the supply side is very much improved. In the proposed control algorithm, the prescribed active current is obtained as a sum of the loss current provided by the DC voltage and the equivalent active current of the unbalanced load. The performance associated with each objective of the compensation is presented and analyzed. The results show that all the power quality indicators meet the specific standards and regulations and prove the validity of the proposed solution.

scholarly journals Способы компенсации высших гармоник напряжения в судовых электроэнергетических системах

2020 ◽  
Author(s):  
A.S. Kornev ◽  
V.I. Kuznetsov ◽  
H. Pan ◽  
A.P. Senkov
Keyword(s):  
Electric Power ◽  
Electric Propulsion ◽  
Frequency Converter ◽  
Electric Power System ◽  
Propulsion Systems ◽  
Higher Harmonics ◽  
Frequency Converters ◽  
Three Phase ◽  
Harmonic Components ◽  
Waveform Distortions

В статье выполнен анализ способов компенсации высших гармоник в судовой сети единой электроэнергетической системы (ЕЭЭС), в составе которой, основным потребителей электроэнергии является система электродвижения (СЭД). Рассмотрены три схемы компенсации высших гармоник, создаваемых неуправляемыми выпрямителями, входящими в состав преобразователей частоты (ПЧ). Проведено компьютерное моделирование фрагмента структуры ЕЭЭС, запатентованной фирмой Siemens , схемы 18-пульсного выпрямителя, а также схемы с двумя 12-пульсными выпрямителями. Результаты моделирования показали, что в структуре ЕЭЭС фирмы Siemens , пропульсивный трансформатор обеспечивает компенсацию только части высших гармоник, из-за чего, искажения формы напряжения в судовой сети могут быть значительными. Схема, содержащая два 12-пульсных выпрямителя, а также трехфазный трансформатор с четырьмя трехфазными обмотками, имеющими сдвиг фаз на 15 электрических градусов, показала наилучшие показатели по качеству тока, обеспечивая эффективную компенсацию 5, 7, 11, 13 гармонических составляющих тока. Предложенная схема с двумя 12-пульсными выпрямителями позволяет в составе ПЧ применить трехуровневые автономные инверторы напряжения, характеризующиеся высоким качеством тока в обмотках гребного электродвигателя.The article analyzes the methods for compensating for higher harmonics in the ship network of the unified electric power system (UEPS), in which the main electric power consumers are electric propulsion systems (EPS). Three compensation schemes for higher harmonics created by uncontrolled rectifiers that are part of frequency converters are considered. Computer simulation of a fragment of the UEPS structure patented by Siemens, an 18-pulse rectifier circuit, and also circuits with two 12-pulse rectifiers were carried out. The simulation results showed that in the Siemens UEPS structure, a propulsive transformer provides compensation for only a part of the higher harmonics, due to which, voltage waveform distortions in the ship network can be significant. The circuit, containing two 12-pulse rectifiers, as well as a three-phase transformer with four three-phase windings having a phase shift of 15 electrical degrees, showed the best current quality indicators, providing effective compensation for 5, 7, 11, 13 harmonic components of the current. The proposed circuit with two 12-pulse rectifiers allows the use of three-level autonomous voltage inverters, which are characterized by high quality current in the windings of the propeller motor, as part of the frequency converter.

scholarly journals A Review of Neurotransmitters Sensing Methods for Neuro-Engineering Research

2019 ◽  
Vol 9 (21) ◽  
pp. 4719 ◽  
Author(s):  
Shimwe Dominique Niyonambaza ◽  
Praveen Kumar ◽  
Paul Xing ◽  
Jessy Mathault ◽  
Paul De Koninck ◽  
...  
Keyword(s):  
Imaging Techniques ◽  
Ongoing Research ◽  
Engineering Research ◽  
Detection Techniques ◽  
In Vivo Detection ◽  
Low Concentrations ◽  
The Subject ◽  
The Brain

Neurotransmitters as electrochemical signaling molecules are essential for proper brain function and their dysfunction is involved in several mental disorders. Therefore, the accurate detection and monitoring of these substances are crucial in brain studies. Neurotransmitters are present in the nervous system at very low concentrations, and they mixed with many other biochemical molecules and minerals, thus making their selective detection and measurement difficult. Although numerous techniques to do so have been proposed in the literature, neurotransmitter monitoring in the brain is still a challenge and the subject of ongoing research. This article reviews the current advances and trends in neurotransmitters detection techniques, including in vivo sampling and imaging techniques, electrochemical and nano-object sensing techniques for in vitro and in vivo detection, as well as spectrometric, analytical and derivatization-based methods mainly used for in vitro research. The document analyzes the strengths and weaknesses of each method, with the aim to offer selection guidelines for neuro-engineering research.

scholarly journals Traceable and Authenticated Key Negotiations via Blockchain for Vehicular Communications

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Yuling Chen ◽  
Xiaohan Hao ◽  
Wei Ren ◽  
Yi Ren
Keyword(s):  
Data Sharing ◽  
Unmanned Vehicles ◽  
Vehicular Communications ◽  
Ongoing Research ◽  
Packet Dropping ◽  
Security Scheme ◽  
Diffie Hellman ◽  
Man In The Middle ◽  
The Subject ◽  
Key Negotiation

While key negotiation schemes, such as those based on Diffie–Hellman, have been the subject of ongoing research, designing an efficient and security scheme remains challenging. In this paper, we propose a novel key negotiation scheme based on blockchain, which can be deployed in blockchain-enabled contexts such as data sharing or facilitating electric transactions between vehicles (e.g., unmanned vehicles). We propose three candidates for flexible selection, namely, key exchanges via transaction currency values through value channels (such as the amount in transactions), automated key exchanges through static scripts,and dynamic scripts, which can not only guarantee key availability with timeliness but also defend against MITM (man-in-the-middle) attacks, packet-dropping attacks, and decryption failure attacks.

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