Energetika最新文献_第5页

Comparative analysis of risks which are accompanied by the use of typical and boundary gases concentrations for the diagnostics of high voltage transformers 高压变压器诊断中使用典型气体浓度和边界气体浓度所伴随的风险的比较分析

Energetika Pub Date : 2018-10-29 DOI: 10.6001/ENERGETIKA.V64I3.3806

O. Shutenko, O. Proskurnia, V. Abramov

{"title":"Comparative analysis of risks which are accompanied by the use of typical and boundary gases concentrations for the diagnostics of high voltage transformers","authors":"O. Shutenko, O. Proskurnia, V. Abramov","doi":"10.6001/ENERGETIKA.V64I3.3806","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I3.3806","url":null,"abstract":"The aim of the scientific research provided in the article is to increase the operational reliability of high-voltage power transformers by reducing the possible risks when diagnosing high-voltage equipment based on the analysis of gases dissolved in oil. We described the method for determining the boundary (typical) gas concentrations by the integral function method, which is recommended by some existing standards, and the author’s method for determining the boundary concentrations of gases ensuring a minimum of possible economic damage in case of taking erroneous decisions. The analysis of boundary concentrations of gases obtained by the method of integral functions and the method of minimum risk showed that boundary values differ significantly for the same data, depending on the method of determination. To determine the reliability of decision-making we used a comparative analysis of risk values that may arise while making a diagnosis of high-voltage transformers based on the analysis of gases dissolved in oil, the boundary values of gas concentrations obtained by the integral function method and the minimum risk method, as well as the boundary values of gas concentrations regulated by known international and national standards were used. The study has revealed that the use of typical values of gas concentrations obtained by integrated distribution functions is accompanied by one of the highest risk values. The lowest risk value is provided by the boundary concentrations obtained by the minimum risk method. The method proposed for determining the boundary values of gas concentrations, taking into account the influence of the most relevant factors, allows significantly lower the values of possible risks and consequently can increase the operational reliability of high-voltage transformers, especially those that are used outside the normative service life.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44595830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Substantiation and the range of application of a new method for heat transfer prediction in condensing inside plain tubes 平面管内冷凝传热预测新方法的建立及应用范围

Energetika Pub Date : 2018-10-29 DOI: 10.6001/ENERGETIKA.V64I3.3807

V. Rifert, V. Sereda, V. Gorin, P. Barabash, A. Solomakha

{"title":"Substantiation and the range of application of a new method for heat transfer prediction in condensing inside plain tubes","authors":"V. Rifert, V. Sereda, V. Gorin, P. Barabash, A. Solomakha","doi":"10.6001/ENERGETIKA.V64I3.3807","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I3.3807","url":null,"abstract":"Since the first work of Tepe and Mueller and until now, there have been published hundreds of studies with the results of heat transfer investigations in vertical and horizontal tubes with vapour condensing of various liquids. Dozens of methods and formulae based both on the results of the theoretical research and on the experimental data have been proposed. The existence of more than 50% discrepancy in different experimental data and various empirical and theoretical relationships is shown. Thus, the absence of both substantiation of different methods and explanations of methods disagreement both between themselves and with different experiments is noted. Also, there are often no remarks concerning boundaries for the use of proposed relationships. There is proposed a simple semi-empirical correlation for heat transfer prediction in condensing inside the plain tubes at the annular and intermediate flow of the phases. This correlation is based on the nature of film condensation process and on the specific features of the results of theoretical solutions. The range of application of complexes, which determine the heat transfer process, is also substantiated. Good convergence of the new method with the experimental data on condensation of steam, carbon dioxide, hydrocarbon refrigerants and other various fluids inside horizontal and vertical tubes is shown.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45378594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Demand-oriented energy supply by the anaerobic digestion of organic waste 以需求为导向的有机废物厌氧消化能源供应

Energetika Pub Date : 2018-10-29 DOI: 10.6001/ENERGETIKA.V64I3.3804

Marco Wehner, W. Müller, A. Bockreis

{"title":"Demand-oriented energy supply by the anaerobic digestion of organic waste","authors":"Marco Wehner, W. Müller, A. Bockreis","doi":"10.6001/ENERGETIKA.V64I3.3804","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I3.3804","url":null,"abstract":"The share of renewable energy is steadily increasing globally. Nevertheless, power generation from renewable energy sources, such as solar and wind energy, is highly dependent on suitable weather conditions and therefore highly fluctuating. Thus, alternatives to compensate fluctuations in the energy production are necessary. Biogas plants have the potential to balance energy generation fluctuations and work independently from unstable weather. Experiments on laboratory scale showed that the storage of food waste had only a marginal impact on its energy content. A rapid acidification due to a lactic acid fermentation leads to a pH decrease and concomitant organic acids increase, preserving the stored organic waste. The pH dropped from initially 4.8 to 4 within the first 2 days of storage. It declined until day 10 to 3.6 and stayed at this level until the end of the experiment. Due to a low pH and a high VFA concentration, only minor amounts of gas were produced during storage. No formation of explosive gas mixtures was detected during the storage. Therefore, no safety precautions are necessary to avoid danger from explosion. The results obtained in laboratory were confirmed by experiments on real scale. Thus, pre-condition of organic waste for a flexible feeding and demand-oriented energy supply is feasible to balance energy generation fluctuations.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46693143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The use of mathematical models for modelling sulphur dioxide sorption on materials produced from fly ashes 使用数学模型模拟粉煤灰产生的材料对二氧化硫的吸附

Energetika Pub Date : 2018-09-14 DOI: 10.6001/energetika.v64i2.3784

N. Czuma, K. Zarębska, P. Baran, P. Gauden

{"title":"The use of mathematical models for modelling sulphur dioxide sorption on materials produced from fly ashes","authors":"N. Czuma, K. Zarębska, P. Baran, P. Gauden","doi":"10.6001/energetika.v64i2.3784","DOIUrl":"https://doi.org/10.6001/energetika.v64i2.3784","url":null,"abstract":"Fly ash-derived zeolites may become an attractive alternative for natural zeolites as well as for zeolites produced out of pure chemicals. A growing awareness of the need to protect the environment is an incentive for the use of waste materials as raw materials for production of microporous, multi-application materials – zeolites. Additionally, environmentally friendly actions undertaken in order to reduce air pollution intensify needs to search for new options for capturing hazardous air pollutants out of flue gases. Zeolites can be used as air pollutants sorbents. In this work there are presented results of sulphur dioxide, one of flue gases components, sorption experiments. The adsorbent used was zeolite synthesized form fly ash from a selected Polish power plant. For the purpose of investigation there were chosen fly ash zeolite samples synthesised with the use of different methods. Parameters were selected in such a way that one type of zeolite material was received. For the purpose of description of received results the mathematical model was used. As a result of experiments carried out it was found that the synthesized materials may be used as sulphur dioxide sorbent. It was found that the sorption capacity is highly connected with the zeolite synthesis method. Despite the fact that the same type of zeolite was received, samples presented differentiated values for capture, due to different conversion factors of fly ash into zeolite materials.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45552074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

The use of cellular communication masts for wind share research 蜂窝通信桅杆在风力共享研究中的应用

Energetika Pub Date : 2018-09-14 DOI: 10.6001/ENERGETIKA.V64I2.3780

V. Bezrukovs, V. Bezrukovs, S. Upnere, L. Gulbe, D. Bezrukovs

{"title":"The use of cellular communication masts for wind share research","authors":"V. Bezrukovs, V. Bezrukovs, S. Upnere, L. Gulbe, D. Bezrukovs","doi":"10.6001/ENERGETIKA.V64I2.3780","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I2.3780","url":null,"abstract":"Prior to the start of any Wind Power Park construction project, it is necessary to carefully assess available wind potential in the selected area. The cost of such investigative studies is considerable – even with a relatively small 70 m tall mast it reaches several tens of thousands of Euros. In order to reduce costs related to wind speed measurements it is suggested to use the existing cellular communication masts that are widely spread in Europe. The study presents a methodological approach and the results of wind speed and wind shear measurements performed with the use of lattice cellular communication masts at the height of up to 100 m. A CFD model of airflow around a cellular communication mast structure was created in order to explore the impact of mast structure on the quality of wind speed measurements. The paper presents the results of the CFD modelling in the form of contour maps depicting the severity of airflow disturbances around the mast. The study is based on experimental measurements conducted in 2018 in three coastal sites of Latvia. At each site wind speed and direction were measured at several heights along with air temperature, humidity and air pressure. The experimentally obtained data in combination with the analysis of modelled CFD results shows the possibility of using cellular communication masts for accurate measurements of wind speed. Overall, the study shows that the proposed approach to wind speed measurements can result in high quality data and reduced overall expenses.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44765638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Performance characteristics of single-stage biohythane production by immobilized anaerobic bacteria 固定化厌氧细菌单段生产生物乙烷的性能特点

Energetika Pub Date : 2018-09-14 DOI: 10.6001/ENERGETIKA.V64I2.3783

D. Ta, Chiu-Yue Lin, C. Chu, T. Ta

引用次数: 2

Investigation of dynamic electricity line rating based on neural networks 基于神经网络的动态电力线路额定值研究

Energetika Pub Date : 2018-09-14 DOI: 10.6001/energetika.v64i2.3781

L. Rácz, B. Németh

{"title":"Investigation of dynamic electricity line rating based on neural networks","authors":"L. Rácz, B. Németh","doi":"10.6001/energetika.v64i2.3781","DOIUrl":"https://doi.org/10.6001/energetika.v64i2.3781","url":null,"abstract":"The security of supply with a high level of operational safety and security has a prominent role in the domestic and international electricity networks. Due to continuous growth of consumer demand, the integration of renewable energy sources and other related changes in the market issues, a number of problems and challenges with the operation and utilization of the existing network have been identified. The need for a higher level of transmission capacity for the transmission network is one of the major challenges in the electricity network.\u0000 Dynamic Line Rating (DLR) is a new generation of transfer capacity methods that can provide a cost-effective solution for the security of supply problems without re-planning the existing infrastructure background. The currently used Static Line Rating allows operators to calculate transfer capacity determined by the worst-case of the weather conditions on the wires of a particular transmission line. Whereas practical applicability shifts to security, the result of this calculation method is almost 95% of time less than the real permissible load of the overhead lines. This potential can be exploited with the DLR by always adjusting the maximum current that can be transmitted on wires. These maximum current values are calculated from the real-time environmental conditions, thus the DLR does not only provide better security of supply, but also a higher level of availability.\u0000 The main issue of the article is to investigate the DLR based on the application of non-analytic computational methods different from the current calculations of the international standards (CIGRE, IEEE). The aim of this research is to create a neural network capable of recognizing patterns based on the weather data of previous years and the actual current values of the wires. In this way, it is not only possible to fine-tune, but also accelerate the applied calculation of maximum load capacity.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48012873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Axisymmetric laminar flow of two-phase medium inside the system of two coaxial pipes 两相介质在两根同轴管道内的轴对称层流

Energetika Pub Date : 2018-09-14 DOI: 10.6001/ENERGETIKA.V64I2.3779

I. Kuzmenko, A. Gourjii

引用次数: 0

Efficient biomass value chains for heat production from energy crops in Ukraine 乌克兰能源作物产热的高效生物质价值链

Energetika Pub Date : 2018-09-14 DOI: 10.6001/ENERGETIKA.V64I2.3782

O. Tryboi

{"title":"Efficient biomass value chains for heat production from energy crops in Ukraine","authors":"O. Tryboi","doi":"10.6001/ENERGETIKA.V64I2.3782","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I2.3782","url":null,"abstract":"The purpose of the paper is to identify the most energy efficient value chains using solid biomass of specially grown energy crops and the most significant parameters affecting their energy efficiency and environmental sustainability. The methodology of Life Cycle Assessment (LCA) was used to determine the energy efficiency of value chains of heat production from energy crops. According to the methodology, the scope of the product system includes the raw material cycle of growing energy crops and the subsystem of transformation with production of thermal energy. Cumulative energy demand and energy yield coefficient were chosen as energy efficiency indicators. The product system was compared with a similar one using natural gas. The non-renewable energy yield coefficient was used to define how many times the energy output was bigger than the input of non-renewable energy. Assessment was conducted for two energy crops: Miscanthus as a typical representative of specially grown grassy energy crops and willow as a typical representative of specially grown woody energy crops. The growing of energy crops in Ukraine for the subsequent production of biofuel in the form of chips and their combustion in biofuel boilers are energetically effective with a maximum transportation distance of 400 km for Miscanthus chips and 180 km for willow chips.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41868372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

EU-CIRCLE methodological approach for assessing the resilience of the interconnected critical infrastructures of the virtual city scenario to climate change 评估虚拟城市场景中相互连接的关键基础设施对气候变化的恢复力的EU-CIRCLE方法

Energetika Pub Date : 2018-07-11 DOI: 10.6001/ENERGETIKA.V64I1.3725

T. Katopodis, A. Sfetsos, Vasiliki-Alexia Varela, S. Karozis, Georgios Karavokyros, G. Eftychidis, I. Gkotsis, G. Leventakis, R. Hedel, I. Koutiva, C. Makropoulos

引用次数: 4