Pub Date : 2018-07-11DOI: 10.6001/ENERGETIKA.V64I1.3724
O. Shutenko
In the article, the gas content of oils in high-voltage equipment with defects of different types is analysed. Typical gas contents and gas ratios for 38 most frequently encountered defects are presented and analysed. The dynamics of the gas content change in equipment during the development of defects was investigated. It is concluded that the development of defects in high-voltage equipment is accompanied by the growth of gas concentrations, which is known and widely used, and it helps stabilize the percentage of gases at strictly defined levels and detect defects at an early stage.
{"title":"Faults diagnostics of high-voltage equipment based on the analysis of the dynamics of changing of the content of gases","authors":"O. Shutenko","doi":"10.6001/ENERGETIKA.V64I1.3724","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I1.3724","url":null,"abstract":"In the article, the gas content of oils in high-voltage equipment with defects of different types is analysed. Typical gas contents and gas ratios for 38 most frequently encountered defects are presented and analysed. The dynamics of the gas content change in equipment during the development of defects was investigated. It is concluded that the development of defects in high-voltage equipment is accompanied by the growth of gas concentrations, which is known and widely used, and it helps stabilize the percentage of gases at strictly defined levels and detect defects at an early stage.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41911612","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}
Pub Date : 2018-07-11DOI: 10.6001/ENERGETIKA.V64I1.3726
Eimantas Neniškis, A. Galinis
The representation of wind power plants electricity generation in economic models for energy planning is problematic, since generation in wind power plants is variable and it is not possible to predict accurately enough wind fluctuations for more than a few days. Often, wind power plants generation patterns from a single historical year are repeated throughout the modelled time period. Typically, this method is used when analysing power system operation in hourly time intervals for all days in a year for each year. However, hourly time resolution is not feasible in large-scale models, which tend to require considerable amounts of computing power. Thus, some kind of time aggregation is needed. On the other hand, currently used methods for models with less than hourly temporal resolution are becoming inadequate because of increasing share of fluctuating electricity production from wind in total power generation. In this article, a methodology for evaluation of wind power plants stochastic electricity generation in power system development models is described. The methodology is based on evaluation of how much time single or multiple wind power plants generate a certain output range during a season or some time period within a year, modelling of output distribution for a typical day of the selected time period, and preparation of electricity output curves. These electricity output curves when modelling wind power plants in models with aggregated time allow to assess fluctuations in generation, observable regularities and enhance the objectivity of balancing power demand assessment, also ensure that electricity generated during a typical day corresponds to electricity generated during the selected time period. This methodology will help to determine the rational perspective power generation mix more accurately and make a better assessment of cost-effectiveness of wind power plants in economic models for energy planning, without significantly increasing the size of already large-scale models.
{"title":"Representation of wind power generation in economic models for long-term energy planning","authors":"Eimantas Neniškis, A. Galinis","doi":"10.6001/ENERGETIKA.V64I1.3726","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I1.3726","url":null,"abstract":"The representation of wind power plants electricity generation in economic models for energy planning is problematic, since generation in wind power plants is variable and it is not possible to predict accurately enough wind fluctuations for more than a few days. Often, wind power plants generation patterns from a single historical year are repeated throughout the modelled time period. Typically, this method is used when analysing power system operation in hourly time intervals for all days in a year for each year. However, hourly time resolution is not feasible in large-scale models, which tend to require considerable amounts of computing power. Thus, some kind of time aggregation is needed. On the other hand, currently used methods for models with less than hourly temporal resolution are becoming inadequate because of increasing share of fluctuating electricity production from wind in total power generation.\u0000 In this article, a methodology for evaluation of wind power plants stochastic electricity generation in power system development models is described. The methodology is based on evaluation of how much time single or multiple wind power plants generate a certain output range during a season or some time period within a year, modelling of output distribution for a typical day of the selected time period, and preparation of electricity output curves. These electricity output curves when modelling wind power plants in models with aggregated time allow to assess fluctuations in generation, observable regularities and enhance the objectivity of balancing power demand assessment, also ensure that electricity generated during a typical day corresponds to electricity generated during the selected time period. This methodology will help to determine the rational perspective power generation mix more accurately and make a better assessment of cost-effectiveness of wind power plants in economic models for energy planning, without significantly increasing the size of already large-scale models.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41973939","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}
Pub Date : 2018-07-11DOI: 10.6001/ENERGETIKA.V64I1.3727
R. Janulionis, G. Dundulis, Rita Kriūkienė, A. Grybėnas
During nuclear power plant (NPP) operation, degradation effects like ageing, corrosion, fatigue, and others may significantly impact component integrity. One of the degradation mechanisms is hydrogen absorption. High levels of hydrogen in zirconium alloys can lead to the formation of zirconium hydrides and that can influence material properties. Therefore, determination of material properties under different levels of hydrogen concentration in zirconium alloys is important. It is not always possible to conduct an experimental testing. Therefore, there is a need for alternative methods for determination of material properties. This article presents the numerical prediction of material properties of zirconium 2.5% niobium alloy with hydrides. According to the objective of the work, numerical prediction was performed using the finite element (FE) method. This was done by creating a finite element model of zirconium hydride embedded in zirconium alloy. The geometry and size of hydride were measured from a real specimen. The size of zirconium alloy surrounding the hydride was selected in such a way that hydride volume part in the model would match experimental measurements. The prognosis results were compared with the experimental data.
{"title":"Numerical prediction of mechanical properties of zirconium alloy with hydrides using finite element method","authors":"R. Janulionis, G. Dundulis, Rita Kriūkienė, A. Grybėnas","doi":"10.6001/ENERGETIKA.V64I1.3727","DOIUrl":"https://doi.org/10.6001/ENERGETIKA.V64I1.3727","url":null,"abstract":"During nuclear power plant (NPP) operation, degradation effects like ageing, corrosion, fatigue, and others may significantly impact component integrity. One of the degradation mechanisms is hydrogen absorption. High levels of hydrogen in zirconium alloys can lead to the formation of zirconium hydrides and that can influence material properties. Therefore, determination of material properties under different levels of hydrogen concentration in zirconium alloys is important. It is not always possible to conduct an experimental testing. Therefore, there is a need for alternative methods for determination of material properties. This article presents the numerical prediction of material properties of zirconium 2.5% niobium alloy with hydrides.\u0000 According to the objective of the work, numerical prediction was performed using the finite element (FE) method. This was done by creating a finite element model of zirconium hydride embedded in zirconium alloy. The geometry and size of hydride were measured from a real specimen. The size of zirconium alloy surrounding the hydride was selected in such a way that hydride volume part in the model would match experimental measurements. The prognosis results were compared with the experimental data.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42990661","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}
Pub Date : 2018-07-11DOI: 10.6001/energetika.v64i1.3723
V. Zubenko, A. Épik, V. Antonenko
The article contains the aggregated results of the development and optimization of laboratory installation for ablative fast pyrolysis performance with productivity 1–4 kg/hour on final products. The experimental data on a series of experiments (>60) with analysis of the influence of a certain range of input parameters on the bio-oil yield and qualitative parameters of output products is presented. The optimization of installation regimes and input parameters for bio-oil yield maximization for different biomass types is performed. It was found that the ratio of three output products is not always optimal maximizing bio-oil yield with respect to energy yield in the products. The maximum achieved bio-oil yield is 51%, with the average level of 44% (by mass rated to the input products). It is revealed that the final bio-oil yield depends mainly on temperature in the reactor, time of biomass particles existence in the reactor, and biomass fraction. The mass distribution for pyrolysis by-products (pyrogas and biochar) is dependent on the initial moisture content of biomass and organization of the condensation process of bio-oil. The energy balance of installation demonstrates the average efficiency of the pyrolysis process on the level of 65% (with maximum 98%) and could be increased to 90% average with a simple reconstruction of installation. On the basis of obtained laboratory data, the scaling of the installation was performed with the development of a commercial prototype with the productivity of 50 kg/hour. On the basis of obtained technical data, the assessment of economic indicators of bio-oil and biochar production with large sized mobile installation has been performed demonstrating a good commercial feasibility of the installation performance.
{"title":"Development and optimization of fast ablative pyrolysis technology in Ukraine","authors":"V. Zubenko, A. Épik, V. Antonenko","doi":"10.6001/energetika.v64i1.3723","DOIUrl":"https://doi.org/10.6001/energetika.v64i1.3723","url":null,"abstract":"The article contains the aggregated results of the development and optimization of laboratory installation for ablative fast pyrolysis performance with productivity 1–4 kg/hour on final products. The experimental data on a series of experiments (>60) with analysis of the influence of a certain range of input parameters on the bio-oil yield and qualitative parameters of output products is presented. The optimization of installation regimes and input parameters for bio-oil yield maximization for different biomass types is performed. It was found that the ratio of three output products is not always optimal maximizing bio-oil yield with respect to energy yield in the products. The maximum achieved bio-oil yield is 51%, with the average level of 44% (by mass rated to the input products). It is revealed that the final bio-oil yield depends mainly on temperature in the reactor, time of biomass particles existence in the reactor, and biomass fraction. The mass distribution for pyrolysis by-products (pyrogas and biochar) is dependent on the initial moisture content of biomass and organization of the condensation process of bio-oil. The energy balance of installation demonstrates the average efficiency of the pyrolysis process on the level of 65% (with maximum 98%) and could be increased to 90% average with a simple reconstruction of installation. On the basis of obtained laboratory data, the scaling of the installation was performed with the development of a commercial prototype with the productivity of 50 kg/hour. On the basis of obtained technical data, the assessment of economic indicators of bio-oil and biochar production with large sized mobile installation has been performed demonstrating a good commercial feasibility of the installation performance.","PeriodicalId":35639,"journal":{"name":"Energetika","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47958944","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}
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