Energija, ekonomija, ekologija最新文献

{"title":"Uticaj solarne elektrane na kvalitet električne energije u niskonaponskoj distributivnoj mreži","authors":"H. Salkić, A. Softić, Amer Salkić","doi":"10.46793/eee20-1-2.137s","DOIUrl":"https://doi.org/10.46793/eee20-1-2.137s","url":null,"abstract":"The electric power system, as an integrated system for transmission, distribution and consumption of electricity, is one of the most complex technical and economic systems today. Customers affect on the voltage quality of power network, but the network also has an impact on customers. All disturbances in the network can disrupt operation of the network and affect on operation of the customers, as well as reduce the level of efficiency and operation life or even seriously damage network. Number of customers is increasing every day, as well as proportion of customers who generate disturbances in the network and, at the same time, are sensitive to them. These circumstances impose the need for frequent monitoring of the network, so the analysis of power quality is not unjustified cost but extremely important and profitable investment. The quality of electricity, as part of the overall quality supply of electricity customers in deregulated conditions of liberal electricity market becomes significant regulatory parameter for network operators and a significant contracting parameter on the electricity market. Network operators are obliged to establish a system of individual measurements and a system of permanent monitoring of power quality parameters to determine the state and improve the parameters to the standardized level. Technical parameters are determined by the recommendations made at the international level and may, but do not need, be legally binding. Maintaining a certain level of voltage quality at some point of the network is the responsibility of electricity distributor. This task distributor executes by limiting of negative effects of producer/customer to the network. Therefore, each electricity producer/customer is obliged to reduce own negative feedback effects (injection of higher harmonics, taking of reactive power, emissions of flickers and loads unbalances) to a prescribed, prearranged, limited values. There are many norms that describe the quality of electricity, but in Europe the best known is EN50160 (issued by CENLEC). This paper presents the approach to measuring the voltage quality at the point of electricity delivery from distributed source into distribution network from the aspect of limiting the negative feedback of distributed source on the voltage quality.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"267 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129136400","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}

{"title":"Da li je pravo vreme za izgradnju velike solarne elektrane u Srbiji?","authors":"N. Rajaković","doi":"10.46793/eee21-2.01r","DOIUrl":"https://doi.org/10.46793/eee21-2.01r","url":null,"abstract":"According to almost all estimates, significant investments in new renewable energy sources in Serbia are needed. Serbia has economically viable potentials of renewable energy sources (RES) (solar energy, wind energy, hydropower, biomass energy, geothermal energy, etc.), so the structure of the production mix in the electricity system should increasingly be based on renewable sources. In this paper, an attempt is made to answer the following questions: does Serbia need new production capacities, does Serbia need new production capacities from RES, and finally, which of the RES would be the most suitable at the moment? The paper assesses whether this is exactly the right moment to accelerate the process of energy transition in Serbia, as well as the opportunity to ensure a more sustainable growth and development through a faster transition to RES. It starts from the fact that increasing the production of electricity from RES, together with measures to increase energy efficiency and decarbonize energy production and consumption, is the backbone of the energy transition and at the same time the essence of Serbia's commitments by joining the Energy Community and accepting international climate agreements. The paper assumes that by increasing the efficiency of the energy sector and use of RES, European policy goals can be achieved in Serbia and that energy sector can be positioned as an engine of stability and sustainable economic development. Secondary effects will lead to increased sustainable employment, reduced public debt and increased competitiveness of the sector. Therefore, the energy transition should be seen as a development opportunity. The construction of large RES plants, especially large solar power plants in Serbia and joining the EU Green Deal, is certainly a signal that Serbia is well on its way to developing a modern, environmentally friendly, competitive and regionally integrated energy system. This will trigger the necessary investments in the modernization of the energy sector and enable the attraction of foreign direct investments. Achieving this vision requires decisive political action at the national and regional levels. Solar projects have the lowest levelized costs of produced kWh of electricity, they are the fastest to implement and they have the least environmental and social impact. Also, large installed capacity can be achieved through a series of large and medium-sized projects that would be territorially distributed in order to reduce the simultaneity of production.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125725695","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}

{"title":"Primena Lagranžove optimizacije na problematiku proizvodnje energije iz obnovljivih izvora","authors":"Vladan Ristić, Nikola Rajaković","doi":"10.46793/eee20-1-2.145r","DOIUrl":"https://doi.org/10.46793/eee20-1-2.145r","url":null,"abstract":"The apparent increase of ecological awareness during the previous decade has led to the need for adaptation of numerous areas of everyday human lives, so they fit the newly developed environmental tendencies. One of the areas in which this necessity was prominent was the power engineering, where, above all, the understanding of production systems was affected, with the turnabout regarding the distancing from the conventional sources and inclining towards the more acceptable renewable sources taking place. However, alongside the undeniable ecological sustainability of these sources, the financial sustainability of their utilization needs to be considered as well, which is why the subject of this paper is the minimization of costs of energy production in these capacities, if the fictious demand area needed to be supplied. It was assumed that this area is separated from transmission and distribution network, with the sole source of energy for the analyzed consumption being the wind, solar and hydro power plants, located in the close vicinity of the examined area. As the objective of the optimization, performed by the method of Lagrange multipliers, the appropriate apportioning of the generation powers in these plants for every hour during the year was selected, so the total yearly costs of supplying the demand were as low as possible. Also, considering the currently promoted methods intended for encouragement of the potential investors to proceed with the projects that encompass renewable sources, the different cases for which the share of renewables included in the feed-in tariff was varied. Finally, in order to provide the full insight into the optimization procedure, for the randomly selected hour of the year and share of feed-in tariff in the generation capacities, the process of calculation of production powers in the described plants and multipliers needed for application of the selected optimization technique was enclosed.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"48 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120968348","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}

{"title":"Metode energetsko – klimatskog planiranja u državama Zapadnog balkana: najnovija dostignuća iz Republike Srbije i Bosne i Hercegovine","authors":"Ilija Batas Bjelić, Nikola Rajaković","doi":"10.46793/eee20-1-2.016bb","DOIUrl":"https://doi.org/10.46793/eee20-1-2.016bb","url":null,"abstract":"Uprkos činjenici da se nalaze u neposrednom susedstvu Evropske Unije i da imaju otvoren pristup najnovijim tehnologijama i instrumentima za sprovođenje energetskih politika, zemlje Zapadnog balkana zaostaju u energetskoj tranziciji. Evropska Unija je aktivirala noviimpuls u sprovođenju energetske tranzicije kroz Evropski zeleni plan, čiji se uticaj na Zapadni Balkan prenosi u vidu nacionalnih energetsko-klimatskih planova čija je izrada u toku. Doprinosi najnovijih dostignuća u Republici Srbiji (npr. nedavno predstavljena Niskougljenična strategija Republike Srbije sa akcionim planom) i Bosni i Hercegovini (aukcije za fotonaponske elektrane) energetskoj tranziciji, biće analizirani korišćenjem tehnike optimizacije na bazi simulacija i pristupom koji se bazira na integraciji sektora. Dodatno, predstaviće se metode modeliranja koje polaze odintegralne procenekojom se obuhvataju međusobni uticaji sistema klima – energija. Osnovna svrha ovih istraživanja je da se donosiocima odluka na Zapadnom balkanu omogući pristup najnovijim znanjima iz održivih energetskih sistema, a građanima više koristi od usvajanja strateških dokumenatai pravednije energetske tranzicije.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124898908","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}

{"title":"Laboratorijskim istraživanjem do izbora mjesta uvođenja stepenovanog vazduha za sagorijevanje u ložište","authors":"N. Hodžić, A. Kazagić, Kenan Kadić","doi":"10.46793/eee20-1-2.089h","DOIUrl":"https://doi.org/10.46793/eee20-1-2.089h","url":null,"abstract":"In general, the mixing the reactants is very important to the process and the rate of combustion of each fuel, especially low-ranked coals with low reactivity. The appropriate excess air coefficient for combustion and the position and mode of supply of individual portions (air sta- ging) of the total air in the furnace are one of the key influ- encing factors for the mixing, respectively the efficiency of the combustion process, and the level of emissions. Today, the air staging (primary, secondary, tertiary and over fire air-OFA) is an indispensable process in the design of new industrial and energy boilers. Also, this measures are used for the reconstru- ction of existing furnace of large boilers. The implementation of this primary measure in the furnace does not require signi- ficant financial resources - the costs of investing in the intro- duction of air staging supply for combustion in the furnace are very low in relation to the multiple positive effects and bene- fits of such a system, especially a lower NOx emissions. However, the first condition for the correct and reliable design of the air staging system in the furnace is the choice of the optimal position for the supply OFA air. Determination of this position on the furnace depends on several factors, primarily the type and characteristics of the fuel, grinding quality, co- mbustion technology, furnace structure, type, number and arra- ngement of burners. On this topic, the Faculty of Mechanical Engineering of the University of Sarajevo, in the Laboratory for Coal and Biomass Combustion, conducted extensive rese- arch on the pulverized combustion of coal blends of the Ce- ntral Bosnia Mining Basin, including co-firing of these coals with waste wood biomass (beech and spruce sawdust). Here is presented some of the results of those NOx emission studies for different fuels and combustion temperatures, depending on the mode of supply and the positions of the combustion air supply in the boiler furnace.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125180499","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}

{"title":"Primena reverznog inženjeringa pri projektovanju radnog kola Peltonove turbine","authors":"Radomir Radiša, Aleksandar Stepanović, Srećko Manasijević, Vesna Mandić, Ljubomir Nešovanović","doi":"10.46793/eee22-3.87r","DOIUrl":"https://doi.org/10.46793/eee22-3.87r","url":null,"abstract":"The paper describes the innovative solution for revitalization of hydro turbines by using the techniques of reverse engineering and virtual production. The application of modern digital tools in developing, designing and producing shows substantial benefits in improving the existing hydro turbine. Model testing in these cases is not necessary to implement because as the basis is used the known geometry of existing hydro turbine runners and buckets. Digital tools allow a relatively easy way to develop new geometry, improve hydraulic performances of turbines and reach a greater level of usefulness with minimal costs. This paper aims to show optimized geometry and improvement of the Pelton turbine performance using the presented approach","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131244063","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}

{"title":"Correlation between Load Current and Temperature for a Power Cable Installed in a Vertical PVC Pipe","authors":"M. Sucurovic, D. Klimenta, D. Tasic, Bojan Perović","doi":"10.46793/eee22-1.47s","DOIUrl":"https://doi.org/10.46793/eee22-1.47s","url":null,"abstract":"The heating of an ethylene-propylene rubber (EPR) insulated cable installed in a vertical polyvinyl chloride (PVC) pipe is analysed in this paper. In particular, this paper considers the heating of an EPR cable used to energize a submersible water pump and analyses the upper part of the well where the space between the EPR cable and the inner surface of the PVC pipe is filled with air. The temperatures of the cable’s surface are determined analytically, and then such temperature values are validated numerically by using the finite element method (FEM) in COMSOL. In addition to these calculations, experiments are performed on a physical model representing the part of the well between the static water level and the solid concrete cover of the well. The percentage deviation of the calculated values for the cable’s surface temperature from the measured ones at different load currents ranges from 1.47% to 4.63%. After the experimental validation of the calculated values for the cable’s surface temperature, an analytic expression (i.e. correlation) that defines the dependence of that temperature on the load current and the pipe’s inner surface temperature is derived. Finally, an analytic expression for the cable load current as a function of the cable’s surface temperature and the pipe’s inner surface temperature is also derived, which can be further used to determine the ampacity of any power cable for known service conditions.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131422331","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}

{"title":"Nаdоgrаdnjа sistеmа zа hlаđеnjе vоdоm sа mоgućnоstimа ispirаnjа","authors":"Valentino Stojkovski, V. Iliev, Filip Stojkovski","doi":"10.46793/eee21-2.48s","DOIUrl":"https://doi.org/10.46793/eee21-2.48s","url":null,"abstract":"This paper presents an analysis of the operating parameters of a water cooling system of the structural part of a furnace for rolling mills preparation. The structural solution of the cooling system is performed as flow, with a constant inflow of fresh water and drainage from the system. Four longitudinal pipes are installed, which are supported by vertical girders. Vertical girders should provide thermal stability to ensure pipe- plate horizontality. The vertical girders are regularly connected to the cooling system by placing pipes direct into the vertical girder, which engages the part of the water supply that cools the vertical girder, and the same water is returned to the cooling system and continuously transferred to the next girder. During operation, due to the quality of cooling water that is not chemically treated, calcium carbonate is formed; the presented impurities clog the flow channels of the cooling system in the vertical girders. The application of CFD analysis reveals the conditions of water flow in the cooling system of vertical girders. From the analysis of the obtained results, it is proposed to upgrade the existing system by installing a flushing system, which will ensure a directed and controlled inflow in the zones of the cooling system. The conceptual solution for the flushing system and the effects of its operation are given in this paper.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115556522","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}

{"title":"Potencijal reindustrijalizacije Republike Srbije uz korišćenje biomase kao obnovljivog vida goriva","authors":"Milica Mladenović, Dragoljub Dakić, N. Petrov","doi":"10.46793/eee22-2.13m","DOIUrl":"https://doi.org/10.46793/eee22-2.13m","url":null,"abstract":"In the context of the current geopolitical situation and energy uncertainty, the aim of the paper is to affirm the use of biomass as a domestic energy source and to point out guidelines for its proper and efficient use. According to the official data of the Ministry of Mining and Energy of the Republic of Serbia, biomass represents by far the greatest potential for renewable energy in the country. Over 60% of the estimated potential of renewable energy in the Republic of Serbia belongs to biomass (not counting large hydropower plants). The possibility of energy use of biomass, further, does not depend on weather conditions, time of day or season, unlike other renewable energy sources such as wind and solar energy. In addition to this and other advantages that biomass as the only carbon - CO2 - neutral renewable fuel has, it should be noted that facilities for the conversion of energy from biomass through combustion are relatively technologically simple and can be produced entirely in our country. If these facilities were used in district heating systems with the possibility of using thermal energy for technological processes in the cultivation and processing of agricultural products even out of the heating season, the potentials and effects of biomass utilization would increase. Facilities for processing and finishing agricultural products (such as dryers) can also be largely produced in the Republic of Serbia. Advantages and the degree of utilization of biomass as a renewable energy source are even more pronounced when used in cogeneration plants. When all the above is considered, it can be concluded that the use of biomass can take a significant place in the overall reindustrialization of our country, which will be discussed in more detail in this paper. The paper also points out some of the obstacles to the realization of these efforts as well as examples of good practice.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124776425","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}

{"title":"Razvoj energetskih zajednica kao aktivna mera za podsticaj pravedne energetske tranzicije u Republici Srbiji","authors":"Miroslav Parović","doi":"10.46793/eee22-2.33p","DOIUrl":"https://doi.org/10.46793/eee22-2.33p","url":null,"abstract":"One of the main features of the energy system of the Republic of Serbia is the extremely high degree of centralization. This situation largely conditions the planning of the energy transition with a \"top-down\" approach. In this way, the existing state of high level of centralization of the energy system is maintained, which largely prevents the elimination of existing injustices. At the same time, the 3D matrix (decarbonisation, decentralization and digitalization) that forms the basis of every modern energy transition is being disrupted. The paper analyses the possibility of changing the approach in planning and implementing the energy transition. Change implies that the bottom-up principle is also respected. In this way, wider involvement of local communities in the energy system is encouraged. The precondition for such a scenario is the development of energy civic initiatives (energy communities) This can be realized through cooperatives, charities or through classic investment business models. Involving the wider community in the process of planning and implementing the energy transition enables adequate remediation of local injustices that occur as a result of the functioning of the energy system as well as the reduction of energy poverty. Overall, the development of energy communities has a positive effect on increasing the level of energy justice and the degree of fairness in the transition to a low-carbon economy and energy.","PeriodicalId":236996,"journal":{"name":"Energija, ekonomija, ekologija","volume":"232 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1900-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123040438","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}