Journal articles on the topic 'District electric network'
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1
Gonzalez-Castellanos, Alvaro, Priyanko Guha Thakurta, and Aldo Bischi. "Congestion management via increasing integration of electric and thermal energy infrastructures." E3S Web of Conferences 238 (2021): 05005. http://dx.doi.org/10.1051/e3sconf/202123805005.
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Congestion caused in the electrical network due to renewable generation can be effectively managed by integrating electric and thermal infrastructures, the latter being represented by large scale District Heating (DH) networks, often fed by large combined heat and power (CHP) plants. The CHP plants could further improve the profit margin of district heating multi-utilities by selling electricity in the power market by adjusting the ratio between generated heat and power. The latter is possible only for certain CHP plants, which allow decoupling the two commodities generation, namely the ones provided by two independent variables (degrees-of-freedom) or by integrating them with thermal energy storage and Power-to-Heat (P2H) units. CHP units can, therefore, help in the congestion management of the electricity network. A detailed mixed-integer linear programming (MILP) optimization model is introduced for solving the network-constrained unit commitment of integrated electric and thermal infrastructures. The developed model contains a detailed characterization of the useful effects of CHP units, i.e., heat and power, as a function of one and two independent variables. A lossless DC flow approximation models the electricity transmission network. The district heating model includes the use of gas boilers, electric boilers, and thermal energy storage. The conducted studies on IEEE 24 bus system highlight the importance of a comprehensive analysis of multi-energy systems to harness the flexibility derived from the joint operation of electric and heat sectors and managing congestion in the electrical network.
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Bolshev, V. E., A. V. Vinogradov, A. V. Vinogradova, A. V. Bukreev, and S. R. Khasanov. "Study of statistical data on the composition of electric distribution networks on the example of a Kaluga region district." E3S Web of Conferences 220 (2020): 01005. http://dx.doi.org/10.1051/e3sconf/202022001005.
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Sustainable operation of the power grid complex is impossible without reliable and high-quality operation of 10/0.4 kV electrical distribution networks, which are the final link in the system for providing consumers with electric energy and are in direct interaction with a specific consumer. The study of statistical information on the composition of distribution networks makes it possible to draw conclusions about electrical network state, to implement recommendations for their development and to compare distribution electrical networks in different regions. This information is especially relevant for analyzing the reliability of power supply to consumers connected to the considered electrical distribution networks. Such indicators of network structure as the length of electric transmission lines of different voltages and power transmission schemes are studied. It also analyzes the number of damages in networks, the causes of these damages, data on the time of planned and emergency outages. This paper considers the structure of 10/0.4 kV electrical distribution networks located on the territory of one of the districts of the Kaluga region. The sample for distribution networks was: 1190 overhead transmission lines and 536 transformer substations. Consumers in the district are 21671 subscribers of individuals and 1986 subscribers of legal entities, that is, a total of 23657 metering points. On the lines of 0.4 kV and 10 kV, the percentage of their isolated design was revealed. The share of single-transformer and two-transformer versions of transformer substations is analyzed.
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Zhou, Zheng, Liu, Liu, Mei, Pan, Shi, and Wu. "Operation Optimization of Multi-District Integrated Energy System Considering Flexible Demand Response of Electric and Thermal Loads." Energies 12, no. 20 (October 10, 2019): 3831. http://dx.doi.org/10.3390/en12203831.
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Multi-district integrated energy system (IES) can make full use of the complementary characteristics of district power and thermal system, and loads in different districts. It can improve the flexibility and economy of system operation, which has a good development prospect. Firstly, based on the general energy transfer model of the district heating network (DHN), the DHN system is described by the basic equations of the heating network and nodes considering the characteristics of the transmission time delay and heat loss in pipelines. A coupling model of DHN and multi-district IES is established. Secondly, the flexible demand response (FDR) model of electric and thermal loads is established. The load characteristics of each district in IES are studied. A shiftable load model based on the electric quantity balance is constructed. Considering the flexibility of the heat demand, a thermal load adjustment model based on the comfort constraint is constructed to make the thermal load elastic and controllable in time and space. Finally, a mixed integer linear programming (MILP) model for operation optimization of multi-district IES with the DHN considering the FDR of electric and thermal loads is established based on the supply and demand sides. The result shows that the proposed model makes full use of the complementary characteristics of electric and thermal loads in different districts. It realizes the coordinated distribution of thermal energy among different districts and improves the efficiency of thermal energy utilization through the DHN. FDR effectively reduces the peak-valley difference of loads. It further reduces the total operating cost by the coordinated operation of the DHN and multi-district IES.
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Masaev, S. Kh, U. Kh Makaev, and M. V. Debiev. "The basic stages of improving the power grid complex functioning of the Chechen Republic." Power engineering: research, equipment, technology 22, no. 4 (November 15, 2020): 43–53. http://dx.doi.org/10.30724/1998-9903-2020-22-4-43-53.
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The article considers the state of the electric power industry functioning of the Chechen Republic. Comparative data on the reception in the network and useful electricity supply of the Chechen Republic in recent years are presented. The total transformer capacity structure of all substations, as well as the power lines total length of Chechenenergo JSC, is considered. The main electric power industry problems of the Chechen power system, which are the lack of own generating capacities, the transformer capacities shortage of substations 110 and 35 kV and the main production assets high level wear of the electric grid economy, are studied. The tasks to reduce the Chechen energy system electric energy losses are considered. The values and causes of the electric energy losses in different district electric networks (RES) of JSC "Chechenenergo" are determined. A comparative analysis of the electrical energy losses in recent years has been performed. Issues related to reactive power in electrical networks are considered. An analysis was carried out to determine the reactive power values in different district electric networks of Chechenenergo JSC. Measures are proposed that contribute to the reactive power normalization and the improvement of technical and economic indicators in electric networks. The networks electrical circuits improvement analysis was carried out to ensure the power supply stability and reliability to consumers in the republic. The production process control system and diagnostics is proposed, which will allow to regulate and coordinate the activities to manage the technical condition, as well as the power system reliability.
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Eremin, Anton, Konstantin Trubitsyn, Sergey Kolesnikov, Igor Kudinov, and Vasily Tkachev. "Computer models of hydraulic systems of district heating." MATEC Web of Conferences 193 (2018): 02028. http://dx.doi.org/10.1051/matecconf/201819302028.
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A mathematical and computer model of a district heating network fed by two heat sources located at significantly different elevation marks has been developed. The model is based on the electrohydraulic analogy of electric current spread in conductors and liquid pressure spread in pipelines, which are described by the same equations. In particular, the first and second Kirchhoff’s laws used in the calculation of electrical networks are applied to calculate the velocities and pressures in a complex multi-ring pipeline system. In order to maximize the approximation of the computer model to the real hydraulic network (in resistance to the process of heating agent flow), the method of automatic identification of the model is applied. This method is an iterative process of changing the hydraulic resistances in pipelines of the model in such a way that the results obtained from the calculations would have the least differences from the experimental data. The accuracy of identification depending on the number of points with known experimental data is 3 – 5%.
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Khomutov, Stanislav O., and Nikolay A. Serebryakov. "Creation of a short-term load forecasting neural network model of electrical engineering complex of section regional electric grid 6-35 kV." Transportation Systems and Technology 6, no. 1 (March 30, 2020): 80–91. http://dx.doi.org/10.17816/transsyst20206180-91.
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Aim: Is developing of short-term load forecasting math model of the electrical engineering complex of the district regional electric grid 6-35 kV with the use of artificial neural networks.
Methods: The tools of regression analysis and deep machine learning were used in the work.
Results: The neural network model for short-term load forecasting of the electrical engineering complex of section regional electric grid 6-35 kV, which considered factors of time, meteorological conditions, disconnections of individual power transmission lines, the operation mode of electricity consumers with a capacity of over 670 kW, the fact of the availability of central heating and water supply, has been obtained.
Conclusion: The developed neural network math model reduces the problem of short-term load forecasting to the search of matrix free coefficients through training on the available statistical data.
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Nikitin, Ye Ye, and O. V. Dutka. "TECHNICAL AND ECONOMIC EFFICIENCY OF COMBINED DISTRICT HEATING WITH LOCAL HEAT SOURCE FOR DISTRICT HOT WATER." Energy Technologies & Resource Saving, no. 1 (March 20, 2020): 34–40. http://dx.doi.org/10.33070/etars.1.2020.4.
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The scheme of combined district heating systems is used, in which centralized heating is used for heating and local heat source is used for hot water supply. A mathematical model has been developed that allows to perform a comparative analysis of the technical and economic characteristics of two scenarios of modernization of the heat supply system: replacement of boilers, heat networks and pumps while using the traditional hot water supply scheme, and replacement of these elements in combination with the installation of a local hot water supply source that provides the hot water supply. hot water by means of a local heat network whose length is substantially smaller than the existing one. Electric heaters and solar collectors with electric heating are proposed as local heat sources. The advantages of combined district heating schemes on the planning horizon of 10 years are shown. The analysis of the influence of various factors on the advantage of the combined scheme of district heating is performed. The developed model can be used for preparation of feasibility studies of projects of energy efficient modernization of district heating systems. Ref. 4, Fig. 7, Tab. 1.
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Balzamov, D. S., V. V. Bronskaya, A. A. Lubnina, Ch B. Minnegalieva, L. E. Khairullina, G. Z. Khabibullina, T. V. Ignashina, and O. S. Kharitonova. "Improving the reliability of the energy supply to the district boiler house." Journal of Physics: Conference Series 2094, no. 5 (November 1, 2021): 052033. http://dx.doi.org/10.1088/1742-6596/2094/5/052033.
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Abstract Currently, measures are being worked out at generation facilities, in particular at district boiler houses, the implementation of which will increase the reliability of both individual elements of the system and the entire energy supply system as a whole, improve its technical and economic indicators, and achieve the target financial indices of the enterprise. As one of such measures, the article considers the ways of organizing a mini-TPP (thermal power plant) on the example of a large district boiler house for the purpose of energy supply for their own needs. This solution will increase the energy independence of the boiler house from the external network, reduce the cost of electricity consumption. The paper presents the results of a technical and economic analysis of options for organizing own generation, taking into account the actual operating conditions of the boiler house, linking the mini-TPP to the existing communications of boiler house, the impact of the joint operation of the mini-TPP and the boiler house on the sanitary zone. Based on the analysis of the loading graphs of the electric equipment of the boiler house, the required capacity of the gas engine generator plant and the place of its installation on the production site are determined. The operation of the gas engine generator plant involves the production of electric energy only for its own needs without issuing it to an external electrical network, in connection with which an automation system is provided that does not allow electricity to be issued to an external network. This restriction is related to the requirements of the technical specifications of the electric grid company.
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Xu, Feng, Yuanchao Tao, Peng Qiu, Chao Ding, Yi Lu, Lebing Zhao, and Hongpei Qin. "Optimal operation of district heat-electric system considering multi-energy flexibility." IOP Conference Series: Earth and Environmental Science 983, no. 1 (February 1, 2022): 012024. http://dx.doi.org/10.1088/1755-1315/983/1/012024.
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Abstract With increasingly integration of the renewable energy, various uncertainties bring a severe challenge to the operation of the district heat-electric system (DHES). In order to enlarge the accommodation of renewable energy, this paper proposes an optimal operation method of integrated electricity and heat system considering the temporal-coupling feature of multi-energy flexibility. Firstly, the models of multi-energy devices are established to describe the energy conversion. The time delay of heat network is considered and the model of DHES is built as well. Then, considering the uncertainty of load, the time-related upward and downward flexibility constraints are established. The objective function of the optimal economic operation problem is formulated as three parts, including the purchasing price, the operation price, and the curtailment penalty of PV. Finally, a case study based on the IEEE 33-bus power distribution grid and 6-node district heating network is conducted to validate the effectiveness of the method.
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Onohaebi, S. O., and S. T. Apeh. "Electricity Network Planning: The Key to Efficient and Reliable Power Supply to Consumers." Advanced Materials Research 62-64 (February 2009): 172–80. http://dx.doi.org/10.4028/www.scientific.net/amr.62-64.172.
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This paper focuses on the need and procedure for the planning of electrical engineering infrastructure for any district/community in order to enhance reliability and efficiency of power supply to consumers. Almost all the towns/cities in Nigeria are unplanned and this has resulted in haphazard approach to Electricity Network Planning and implementation. A detailed theory, methodology and technical considerations, in compliance with both National and International standards are discussed in this paper. A proposed University campus was used to demonstrate the procedures involved in electricity network planning in order to achieve an efficient power supply. This involves the electric power supply, design concepts, load estimates and analysis, network distribution/equipment and sizing of cables and electrical panels taking into account the various modes of distribution. This paper also drew a simple analogy between Benin City and the Federal Capital Territory, Abuja, to illustrate the objective of the paper while highlighting the merits associated with planned electrical engineering infrastructure and suggested the ways to remedy the unplanned networks in Nigeria.
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Rušeljuk, Pavel, Kertu Lepiksaar, Andres Siirde, and Anna Volkova. "Economic Dispatch of CHP Units through District Heating Network’s Demand-Side Management." Energies 14, no. 15 (July 28, 2021): 4553. http://dx.doi.org/10.3390/en14154553.
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Optimisation of heat and electrical load distribution, where the objective function is the maximum efficiency of the CHP unit for a given load range, can be done considering the limitations of electrical power and the heat load. Simulating a real CHP unit with a district heating network shows that demand-side management can improve the overall economic efficiency of the CHP plant and increase the unit’s operating range in the electricity spot market. Economic dispatch makes it possible to determine a reasonable additional increase in the electric power of the CHP unit, and to optimise the supply temperature and mass flow of the district heating network. The results obtained and the analysis performed indicate that the proposed methodology provides logical results and can be used to calculate the efficiency indicators of the cogeneration of electrical and thermal energy. The problem of optimising the operating mode of the CHP unit was solved, which allows us to determine the optimal additional increase in the unit’s electrical load at a given heat load of consumers, which on average increases the CHP unit’s efficiency up to an additional 1.5%.
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Polkovskaya, M. N., and M. A. Yakupova. "Analysis of the Causes of Emergency Shutdowns on Electric Networks." Journal of Physics: Conference Series 2096, no. 1 (November 1, 2021): 012130. http://dx.doi.org/10.1088/1742-6596/2096/1/012130.
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Abstract The paper analyses the causes of emergency outages on electric networks according to the data of the Pravoberezhny district of Irkutsk for 2008-2017, according to which 82% of failures of elements of the electric network are caused by breakdowns and equipment failure; 9% are due to the influence of external factors; 5% occurred due to natural and climatic reasons, 4% – due to other circumstances. The largest number of outages due to operational reasons occurs due to damage to cable and overhead lines. Accidents caused by the influence of external factors are mainly associated with the negative impact of people, animals and birds. Equipment failures related to natural and climatic factors are mainly due to wind or thunderstorms. Other circumstances, as a rule, include staff errors and unidentified reasons. Calculations of undersupply of electricity and economic losses caused by interruptions in power supply were made. It should be noted that in order to reduce the number of equipment failures, it is necessary to carry out timely maintenance and reconstruction of various elements of electrical networks.
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Volkova, Anna, Aleksandr Hlebnikov, Aleksandr Ledvanov, Tanel Kirs, Urmas Raudsepp, and Eduard Latõšov. "District Cooling Network Planning. A Case Study of Tallinn." International Journal of Sustainable Energy Planning and Management 34 (May 25, 2022): 63–78. http://dx.doi.org/10.54337/ijsepm.7011.
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The planning procedure for district cooling as an urban system was presented and carried out using the example of the Tallinn city centre. The following steps were described in detail: cooling demand determination, cooling generation planning and cooling transition analysis. Based on the three proposed methods (average specific cooling load, satellite imagery analysis of a specific building, counting the number of fans in dry coolers and the combination method), the cooling capacity of the evaluated district was estimated at 63.2 MW. In terms of cooling generation, the analysis shows that seawater for free cooling can cover up to 55% of the annual cooling consumption. Electric chillers and absorption chillers that use surplus heat can cover the rest of the district cooling demand. The district cooling network was designed for three scenarios: with one generating unit, with two generating units and a looped network. Despite the fact that the looped network is the most expensive option, this type of solution is considered feasible as it will make it easier to connect new consumers.
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Richert, Thibaut Pierre, Tue Vissing Jensen, Oliver Gehrke, and Henrik WIlliam Bindner. "Operation of supermarket refrigeration units: a coupled district heating and electric network approach." IET Energy Systems Integration 2, no. 2 (May 15, 2020): 80–91. http://dx.doi.org/10.1049/iet-esi.2019.0059.
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Zapanov, Oleg V., and Lidiia I. Kovernikova. "On the power quality of electrical energy supplied to joint stock company “Aleksandrovsky mine”." E3S Web of Conferences 209 (2020): 07012. http://dx.doi.org/10.1051/e3sconf/202020907012.
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Joint Stock Company (JSC) “Mine Aleksandrovsky” is located in the Mogochinsky district of the Trans-Baikal Territory. “Mine Aleksandrovsky” concluded an energy supply agreement with JSC “Chitaenergosbyt” for the purchase of electric energy from it. In accordance with the contract, the electric energy supplier undertakes to supply electric energy that meets the requirements of the current legislation of the Russian Federation. The power quality in the Trans-Baikal Territory in most regions does not meet the requirements of State Standard 32144-2013. Suppliers and the network organization are responsible to consumers for the reliability of its electric energy supply and its quality within the boundaries of their electric networks. Despite the obligations of the contract, the electric energy supplied to “Mine Alexandrovsky” does not meet the requirements. In 2017 the ball mill engine in the shredding department of the gold recovery factory failed as a result of power outages and the supply of low power quality through the 6 kV line. The article provides information on interruptions in power supply over the years of operation of the enterprise, the results of analysis of the power quality, information on damage to electrical equipment caused by low power quality, and economic damage.
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Sun, Bo. "Study on Charging Method with Electric Vehicle Plug-in Distributed Network of Residential District." Journal of Information and Computational Science 11, no. 18 (December 10, 2014): 6825–35. http://dx.doi.org/10.12733/jics20105056.
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Maninnerby, Bergerland, Lazarou, and Theocharis. "Electric Vehicle Penetration in Distribution Network: A Swedish Case Study." Applied System Innovation 2, no. 3 (June 28, 2019): 19. http://dx.doi.org/10.3390/asi2030019.
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This study aims to simulate the use of renewable energy in the form of different energy sources, such as solar cells, district heating, and in the presence of battery storage and for high penetration of electric vehicles in a typical Swedish power grid. The EnergyPLAN software is used. The purpose is to examine the demands in order to cope with the needs that may arise and to create a better understanding of how renewable energy affects the power balance and future investments in the case of a typical Swedish distribution system. The importance of this research is mainly based on the fact that it represents a real network, as it operates today, which is analyzed using the expected electric vehicle penetration. The aim is to investigate the expansion needs for maintaining the current quality for service despite the addition of new loads. In addition, the regional and national special regulatory and operational requirements are taken into account and described in this work.
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Pyatin, Andrey, Aleksander Shempelev, and Ekaterina Popova. "Improving the efficiency of heating boiler plants by using the variable-frequency drive with different methods of heat supply regulation." MATEC Web of Conferences 245 (2018): 07020. http://dx.doi.org/10.1051/matecconf/201824507020.
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The aim of the work is to improve the energy efficiency of heating boiler plants by reducing the spe-cific electric energy consumption for heat supply by using the variable-frequency drive (VFD) with different methods of heat supply regulation. Hydraulic and thermal calculations of the heating net-work are performed on the example of the real district heating system. Heat network temperature charts of district heating are selected and calculated considering preservation of high quality of district heating. The description of the calculation algorithm of the research and the results of the calculation of the basic mode of district heating heat supply according to the standard temperature chart of varia-ble temperature control are given in the article. Places of installation of VFD are determined on the base of the basic mode. The results of calculation of three different methods of heat supply regulation are presented: standard heat network temperature chart of variable temperature control with using the VFD, extended heat network temperature chart of constant temperature/variable flow control, extend-ed heat network temperature chart using the VFD.
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Rakhimov, O. S., D. N. Mirzoev, and E. I. Grachieva. "Experimental study of quality and electricity losses in low voltage rural electric networks." Power engineering: research, equipment, technology 23, no. 3 (July 20, 2021): 224–37. http://dx.doi.org/10.30724/1998-9903-2021-23-3-209-224-237.
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THE PURPOSE. Due to the increase in the number of farms in the Devashtichsky district of the Sughd region of Tajikistan, over the past 3-4 years, a disproportionate distribution of electricity in the 0.4 kV network has been observed. Unbalance currents of phase loads in relation to asymmetric phase voltages at the terminals of consumers of a three-phase network cause additional losses of electricity, which can reach 21% of the standard losses. In the decree of the President of the Republic of Tajikistan dated May 10, 2009 No. 29 “On energy saving and reduction of electricity losses” it is indicated that there is a need to study the quality of electricity in rural 0.4 kV networks and its compliance with GOST 32144. 2013, as well as an assessment of losses electricity in its distribution structure is an important task in the field of rural electricity. METHODS. A single-line diagram of a 0.4 kV network with initial parameters, which were refined during the survey of the network, and the current loads of outgoing lines were investigated. Experimental studies of the quality of electricity and assessment of the level of losses in the low- voltage network were carried out using a complex measuring device «Energotester» PKE - A - C4. RESULTS. The studies allowed obtaining data on the daily consumption of electricity in individual outgoing lines, information on the characteristics of consumers, digital information (database) on indicators of the quality of electricity in low-voltage networks. CONCLUSIONS. It has been established that the main factors influencing the losses of electricity in low-voltage networks are: incommensurability of the power of transformers of transformers and consumers, uneven loading of individual phases, a significant effect of individual converters on the quality of energy. Measures are forecasted to reduce losses and improve the quality of electricity in low-voltage rural networks of 0.4 kV.
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Rakhimov, O. S., D. N. Mirzoev, and E. I. Grachieva. "Experimental study of quality and electricity losses in low voltage rural electric networks." Power engineering: research, equipment, technology 23, no. 3 (July 20, 2021): 209–22. http://dx.doi.org/10.30724/1998-9903-2021-23-3-209-222.
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THE PURPOSE. Due to the increase in the number of farms in the Devashtichsky district of the Sughd region of Tajikistan, over the past 3-4 years, a disproportionate distribution of electricity in the 0.4 kV network has been observed. Unbalance currents of phase loads in relation to asymmetric phase voltages at the terminals of consumers of a three-phase network cause additional losses of electricity, which can reach 21% of the standard losses. In the decree of the President of the Republic of Tajikistan dated May 10, 2009 No. 29 “On energy saving and reduction of electricity losses” it is indicated that there is a need to study the quality of electricity in rural 0.4 kV networks and its compliance with GOST 32144. 2013, as well as an assessment of losses electricity in its distribution structure is an important task in the field of rural electricity. METHODS. A single-line diagram of a 0.4 kV network with initial parameters, which were refined during the survey of the network, and the current loads of outgoing lines were investigated. Experimental studies of the quality of electricity and assessment of the level of losses in the low- voltage network were carried out using a complex measuring device «Energotester» PKE - A - C4. RESULTS. The studies allowed obtaining data on the daily consumption of electricity in individual outgoing lines, information on the characteristics of consumers, digital information (database) on indicators of the quality of electricity in low-voltage networks. CONCLUSIONS. It has been established that the main factors influencing the losses of electricity in low-voltage networks are: incommensurability of the power of transformers of transformers and consumers, uneven loading of individual phases, a significant effect of individual converters on the quality of energy. Measures are forecasted to reduce losses and improve the quality of electricity in low-voltage rural networks of 0.4 kV.
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Croce, Vincenzo, Giuseppe Raveduto, Matteo Verber, and Denisa Ziu. "Combining Machine Learning Analysis and Incentive-Based Genetic Algorithms to Optimise Energy District Renewable Self-Consumption in Demand-Response Programs." Electronics 9, no. 6 (June 6, 2020): 945. http://dx.doi.org/10.3390/electronics9060945.
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The recent rise of renewable energy sources connected to the distribution networks and the high peak consumptions requested by electric vehicle-charging bring new challenges for network operators. To operate smart electricity grids, cooperation between grid-owned and third-party assets becomes crucial. In this paper, we propose a methodology that combines machine learning with multi-objective optimization to accurately plan the exploitation of the energy district’s flexibility with the objective of reducing peak consumption and avoiding reverse power flow. Using historical data, acquired by the smart meters deployed on the pilot district, the district’s power profile can be predicted daily and analyzed to identify potentially critical issues on the network. District’s resources, such as electric vehicles, charging stations, photovoltaic panels, buildings energy management systems, and energy storage systems, have been modeled by taking into account their operational constraints and the multi-objective optimization has been adopted to identify the usage pattern that better suits the distribution operator’s (DSO) needs. The district is subject to incentives and penalties based on its ability to respond to the DSO request. Analysis of the results shows that this methodology can lead to a substantial reduction of both the reverse power flow and peak consumption.
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Tolmachev, Alexander V., Evgeny V. Sinitsyn, and Dmitrii A. Brusyanin. "Transport system modelling based on analogies between road networks and electrical circuits." R-Economy 1, no. 2 (July 11, 2019): 92. http://dx.doi.org/10.15826/recon.2019.5.2.010.
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This article describes a probabilistic mathematical model which can be used to analyse traffic flows in a road network. This model allows us to calculate the probability of distribution of vehicles in a regional road network or an urban street network. In the model, the movement of cars is treated as a Markov process. This makes it possible to formulate an equation determining the probability of finding cars at key points of the road network such as street intersections, parking lots or other places where cars concentrate. For a regional road network, we can use cities as such key points. This model enables us, for instance, to use the analogues of Kirchhoff First Law (Ohm's Law) for calculation of traffic flows. This calculation is based on the similarity of a real road network and resistance in an electrical circuit. The traffic flow is an analogue of the electric current, the resistance of the section between the control points is the time required to move from one key point to another, and the voltage is the difference in the number of cars at these points. In this case, well-known methods for calculating complex electrical circuits can be used to calculate traffic flows in a real road network. The proposed model was used to calculate the critical load for a road network and compare road networks in various regions of the Ural Federal District.
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Grzebielec, Andrzej, Artur Rusowicz, Maciej Jaworski, and Rafał Laskowski. "Possibility of using adsorption refrigeration unit in district heating network." Archives of Thermodynamics 36, no. 3 (September 1, 2015): 15–24. http://dx.doi.org/10.1515/aoter-2015-0019.
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Abstract Adsorption refrigeration systems are able to work with heat sources of temperature starting with 50 °C. The aim of the article is to determine whether in terms of technical and economic issues adsorption refrigeration equipment can work as elements that produce cold using hot water from the district heating network. For this purpose, examined was the work of the adsorption air conditioning equipment cooperating with drycooler, and the opportunities offered by the district heating network in Warsaw during the summer. It turns out that the efficiency of the adsorption device from the economic perspective is not sufficient for production of cold even during the transitional period. The main problem is not the low temperature of the water supply, but the large difference between the coefficients of performance, COPs, of adsorption device and a traditional compressor air conditioning unit. When outside air temperature is 25 °C, the COP of the compressor type reaches a value of 4.49, whereas that of the adsorption device in the same conditions is 0.14. The ratio of the COPs is 32. At the same time ratio between the price of 1 kWh of electric power and 1 kWh of heat is only 2.85. Adsorption refrigeration equipment to be able to compete with compressor devices, should feature COPads efficiency to be greater than 1.52. At such a low driving temperature and even changing the drycooler into the evaporative cooler it is not currently possible to achieve.
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Ivanyo, Ya M., I. V. Naumov, and M. N. Polkovskaya. "FAILURE SIMULATION OF ELEMENTS OF THE CITY ELECTRIC NETWORK (10 KV) BY THE EXAMPLE OF THE PRAVOBEREZHNIY DISTRICT OF THE IRKUTSK CITY." Vestnik Altajskogo gosudarstvennogo agrarnogo universiteta, no. 9 (2021): 87–98. http://dx.doi.org/10.53083/1996-4277-2021-203-09-87-98.
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The paper presents mathematical models for probabil-istic evaluation and forecasting of emergency shutdowns in electric networks by the example of the Pravoberezhniy District of the Irkutsk City from 2008 through 2017. At the first stage, the autocorrelation function of the parameter series is determined to estimate its randomness. According to the calculated statistical parameters and the consent criteria, a number of equipmentfailures may be described by a three-parameter gamma distribution. A method of two-level identification of extreme (maximum and minimum) values of the parameter under study is proposed; accord-ing to this method, a significant polynomial trend is ob-tained for predicting the largest number of failures. The evaluation of the presence of trends based on monthly data showed that polynomial and power trends may be used to predict failures on electric networks. At the same time, sig-nificant trends were identifiedonly for January, February, May and December. At the next stage, trend-seasonal models are constructed; the least squares method is used to calculate their components. According to the obtained seasonality indices, the greatest increase in emergency shutdowns takes place in April and July, and a decrease -in February and March. On the basis of the correlation-regression model, factor models of failures of electrical network elements and the accumulated average daily tem-peratures for months and time are constructed. Linear and nonlinear models with and without trends are obtained. To evaluate the accuracy of the forecasts of the obtained models, the results of the retrospective forecast for 2017 were compared with the actual values. According to the resultsobtained for predicting failures on electric networks in February, June, July and September, the best result is shown by a trend-seasonal model, in May -a polynomial trend, in November -a factorial one taking into account time, in March, May and October-a nonlinear regression equation, and in December -a power trend. There are no qualitative forecast models for the months of January, April, and August. In this regard, the values of emergency shut-downs on these months may be estimated using a proba-bilistic model.
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Branchini, Lisa, Andrea De Pascale, Francesco Melino, and Noemi Torricelli. "Optimum Organic Rankine Cycle Design for the Application in a CHP Unit Feeding a District Heating Network." Energies 13, no. 6 (March 12, 2020): 1314. http://dx.doi.org/10.3390/en13061314.
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Improvement of energy conversion efficiency in prime movers has become of fundamental importance in order to respect EU 2020 targets. In this context, hybrid power plants comprising combined heat and power (CHP) prime movers integrated with the organic Rankine cycle (ORC) create interesting opportunities to additionally increase the first law efficiency and flexibility of the system. The possibility of adding supplementary electric energy production to a CHP system, by converting the prime movers’ exhaust heat with an ORC, was investigated. The inclusion of the ORC allowed operating the prime movers at full-load (thus at their maximum efficiency), regardless of the heat demand, without dissipating not required high enthalpy-heat. Indeed, discharged heat was recovered by the ORC to produce additional electric power at high efficiency. The CHP plant in its original arrangement (comprising three internal combustion engines of 8.5 MW size each) was compared to a new one, involving an ORC, assuming three different layout configurations and thus different ORC off-design working conditions at user thermal part-load operation. Results showed that the performance of the ORC, on the year basis, strongly depended on its part-load behavior and on its regulation limits. Indeed, the layout that allowed to produce the maximum amount of ORC electric energy per year (about 10 GWh/year) was the one that could operate for the greatest number of hours during the year, which was different from the one that exhibited the highest ORC design power. However, energetic analysis demonstrated that all the proposed solutions granted to reduce the global primary energy consumption of about 18%, and they all proved to be a good investment since they allowed to return on the investment in barely 5 years, by selling the electric energy at a minimum price equal to 70 EUR/MWh.
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Wang, Cheng, Zhou Gao, Peng Yang, Zhenpo Wang, and Zhiheng Li. "Electric Vehicle Charging Facility Planning Based on Flow Demand—A Case Study." Sustainability 13, no. 9 (April 28, 2021): 4952. http://dx.doi.org/10.3390/su13094952.
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The location of electric vehicle charging facilities is of great significance in promoting the use of electric vehicles. Most existing electric vehicle location models, including the flow refueling location model (FRLM) and its flexible reformulation (FRFRLM), are based on flow demand. At present, these models cannot effectively deal with large-scale traffic networks within a limited time, and there has been little comparison of their relative benefits and limitations. Additionally, there have been few evaluations of the actual construction and location of charging facilities in cities. This paper describes an algorithm that can solve the large-scale transportation network problem within a reasonable time. Using this algorithm, the FRLM and FRFRLM models are compared in a case study focused on Jiading District, Shanghai, China, which provides some direction for the future development of flow demand models. Finally, to evaluate the actual construction of urban charging facilities, this paper presents an algorithm that can map the actual charging facilities to the transportation network, and compares the actual construction situation with the model output. This enables a comprehensive evaluation of the actual construction of charging facilities and provides guidance for future construction.
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Latosov, Eduard, Anna Volkova, Andres Siirde, Martin Thalfeldt, and Jarek Kurnitski. "The Impact of Parallel Energy Consumption on the District Heating Networks." Environmental and Climate Technologies 23, no. 1 (March 1, 2019): 1–13. http://dx.doi.org/10.2478/rtuect-2019-0001.
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Abstract The aim of this study is to evaluate and compare the impacts of heat recovery ventilation (HRV) and exhaust air heat pump (EAHP)-based solutions used in renovated buildings, which make it possible to reach performance class C in district heating (DH) area CO2 emissions, primary energy consumption and total energy costs for consumers. Evaluation is based on the methodology presented in the previous research paper [1]. Calculation results show that the use of EAHP has a negative impact on DH sustainability (heat losses in the DH network, DH heat price, reduced consumption of DH heat) and CO2 emissions related to energy delivery (heat and electricity) to consumers in the DH area. Positive aspects of the EAHP use include the fact that almost the same primary energy consumption level can be achieved with lesser (up to 7 %) annual costs (annual capital costs, DH heat costs and electricity costs) and lower initial investments (about 10 %). At the same time, every renovated building with EAHP will experience a negative impact on heat prices. In DH areas where almost all buildings are renovated with EAHP, cost savings are not as evident compared to buildings with HRV in DH areas where the use of parallel consumption solutions (EAHP) is minimized. It is reasonable to promote these renovation packages and solutions that benefit the building’s primary energy reduction, and also do not increase electric energy consumption (additional electric power generators are needed) and do not damage DH networks.
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He, Liangce, Zhigang Lu, Lili Pan, Hao Zhao, Xueping Li, and Jiangfeng Zhang. "Optimal Economic and Emission Dispatch of a Microgrid with a Combined Heat and Power System." Energies 12, no. 4 (February 14, 2019): 604. http://dx.doi.org/10.3390/en12040604.
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With the rapid development of the new concept of energy internet, electric power systems often need to be investigated together with thermal energy systems. Additionally, to reduce pollution from gas emissions, it is very important to study the economic and emission dispatch of integrated electrical and heating systems. Hence, this paper proposes a multi-objective optimization dispatch model for a microgrid (MG) with a combined heat and power (CHP) system. This CHP-based MG system consists of a CHP unit, a wind turbine, a PV system, a fuel cell, an electric boiler, an electric storage, and a heat storage. It can exchange electricity with the distribution network and exchange heat with the district heating network. Minimum economic cost and minimum environmental cost are considered as the two objectives for the operation of this CHP-based MG system. To solve the two objective optimization problem, the multi-objective bacterial colony chemotaxis algorithm is utilized to obtain the Pareto optimal solution set, and the optimal solution is chosen by the Technique for Order of Preference by Similarity to Ideal Solution method. Finally, numerical case studies demonstrate the effectiveness of proposed model and method for the optimal economic and emission dispatch of the CHP-based MG system.
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Buffa, Simone, Anton Soppelsa, Mauro Pipiciello, Gregor Henze, and Roberto Fedrizzi. "Fifth-Generation District Heating and Cooling Substations: Demand Response with Artificial Neural Network-Based Model Predictive Control." Energies 13, no. 17 (August 21, 2020): 4339. http://dx.doi.org/10.3390/en13174339.
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District heating and cooling (DHC) is considered one of the most sustainable technologies to meet the heating and cooling demands of buildings in urban areas. The fifth-generation district heating and cooling (5GDHC) concept, often referred to as ambient loops, is a novel solution emerging in Europe and has become a widely discussed topic in current energy system research. 5GDHC systems operate at a temperature close to the ground and include electrically driven heat pumps and associated thermal energy storage in a building-sited energy transfer station (ETS) to satisfy user comfort. This work presents new strategies for improving the operation of these energy transfer stations by means of a model predictive control (MPC) method based on recurrent artificial neural networks. The results show that, under simple time-of-use utility rates, the advanced controller outperforms a rule-based controller for smart charging of the domestic hot water (DHW) thermal energy storage under specific boundary conditions. By exploiting the available thermal energy storage capacity, the MPC controller is capable of shifting up to 14% of the electricity consumption of the ETS from on-peak to off-peak hours. Therefore, the advanced control implemented in 5GDHC networks promotes coupling between the thermal and the electric sector, producing flexibility on the electric grid.
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Shehadeh, Maha, Emily Kwok, Jason Owen, and Majid Bahrami. "Integrating Mobile Thermal Energy Storage (M-TES) in the City of Surrey’s District Energy Network: A Techno-Economic Analysis." Applied Sciences 11, no. 3 (January 30, 2021): 1279. http://dx.doi.org/10.3390/app11031279.
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The City of Surrey in British Columbia, Canada has recently launched a district energy network (DEN) to supply residential and commercial buildings in the Surrey Centre area with hot water for space and domestic hot water heating. The network runs on natural gas boilers and geothermal exchange. However, the City plans to transition to low-carbon energy sources and envisions the DEN as a key development in reaching its greenhouse gas emissions (GHG) reduction targets in the building sector. Harvesting and utilizing waste heat from industrial sites using a mobile thermal energy storage (M-TES) is one of the attractive alternative energy sources that Surrey is considering. In this study, a techno-economic analysis (TEA) was conducted to determine the energy storage density (ESD) of the proposed M-TES technology, costs, and the emission reduction potential of integrating waste heat into Surrey’s DEN. Three transportation methods were considered to determine the most cost-effective and low-carbon option(s) to transfer heat from industrial waste heat locations at various distances (15 km, 30 km, 45 km) to district energy networks, including: (i) a diesel truck; (ii) a renewable natural gas-powered (RNG) truck, and (iii) an electric truck. To evaluate the effectiveness of M-TES, the cost of emission reduction ($/tCO2e avoided) is compared with business as usual (BAU), which is using a natural gas boiler only. Another comparison was made with other low carbon energy sources that the city is considering, such as RNG/biomass boiler, sewer heat recovery, electric boiler, and solar thermal. The minimum system-level ESD required to makes M-TES competitive when compared to other low carbon energy sources was 0.4 MJ/kg.
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Wang, Wei, Sitong Jing, Yang Sun, Jizhen Liu, Yuguang Niu, Deliang Zeng, and Can Cui. "Combined heat and power control considering thermal inertia of district heating network for flexible electric power regulation." Energy 169 (February 2019): 988–99. http://dx.doi.org/10.1016/j.energy.2018.12.085.
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Testi, Daniele, Paolo Conti, Eva Schito, Luca Urbanucci, and Francesco D’Ettorre. "Synthesis and Optimal Operation of Smart Microgrids Serving a Cluster of Buildings on a Campus with Centralized and Distributed Hybrid Renewable Energy Units." Energies 12, no. 4 (February 23, 2019): 745. http://dx.doi.org/10.3390/en12040745.
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Micro-district heating networks based on cogeneration plants and renewable energy technologies are considered efficient, viable and environmentally-friendly solutions to realizing smart multi-energy microgrids. Nonetheless, the energy production from renewable sources is intermittent and stochastic, and cogeneration units are characterized by fixed power-to-heat ratios, which are incompatible with fluctuating thermal and electric demands. These drawbacks can be partially overcome by smart operational controls that are capable of maximizing the energy system performance. Moreover, electrically driven heat pumps may add flexibility to the system, by shifting thermal loads into electric loads. In this paper, a novel configuration for smart multi-energy microgrids, which combines centralized and distributed energy units is proposed. A centralized cogeneration system, consisting of an internal combustion engine is connected to a micro-district heating network. Distributed electric heat pumps assist the thermal production at the building level, giving operational flexibility to the system and supporting the integration of renewable energy technologies, i.e., wind turbines, photovoltaic panels, and solar thermal collectors. The proposed configuration was tested in a hypothetical case study, namely, a University Campus located in Trieste, Italy. The system operation is based on a cost-optimal control strategy and the effect of the size of the cogeneration unit and heat pumps was investigated. A comparison with a conventional configuration, without distributed heat pumps, was also performed. The results show that the proposed configuration outperformed the conventional one, leading to a total-cost saving of around 8%, a carbon emission reduction of 11%, and a primary energy saving of 8%.
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Hampo, Chima Cyril, Ainul Bt Akmar, and Mohd Amin Abd Majid. "Life Cycle Assessment of an Electric Chiller Integrated with a Large District Cooling Plant." Sustainability 13, no. 1 (January 4, 2021): 389. http://dx.doi.org/10.3390/su13010389.
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District cooling (DC) systems have recently proven to be more economically and environmentally viable as compared to conventional cooling techniques. In most DC setups, electric centrifugal chillers (ECCs) are installed to provide chilled water (CW) to charge the thermal energy storage (TES) tank or for direct CW supply to the DC network. The operation of these ECC systems consumes most of the electrical power supplied to the entire DC plant; this therefore strengthens the need to conduct a comprehensive environmental assessment in order to quantify the indirect ecological impact resulting from the energy consumed in the ECC system operation. In order to achieve this, a case study was conducted of four ECC systems with a use-life of 25 years installed in a large DC plant in Malaysia. A gate-to-gate life cycle assessment (LCA) methodology was adopted to analyze the environmental performance of the system setup. The result of the study year reveals that April and June account for the highest and lowest environmental impact, respectively. The influence of climatic temperature conditions on the monthly cooling and environmental load distribution was also observed from the results. Finally, in substantiating the study’s investigation, environmental performance based on the composition of two different electricity fuel mixes is discussed and compared. The results revealed a drastic decrease in environmental load as the ratio of non-renewable energy sources decreased in the composition of the mix, thereby reducing the contribution of the overall environmental impact of the ECC systems’ use phase.
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Lin, Da, Chouwei Ni, Xuesong Zhang, and Junhao Huang. "An optimal scheduling method for integrated power and heat system with multiple thermal flexibilities." E3S Web of Conferences 252 (2021): 01016. http://dx.doi.org/10.1051/e3sconf/202125201016.
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Integrated power and heat system (IPHS) is a typical multi-energy system which involves power system and district heating system (DHS). The utilization of thermal flexibilities in the joint operation of power system and district heating system has shown the potential to improve energy efficiency and economic performance. In this paper, an optimal scheduling method for IPHS with multiple thermal flexibilities is proposed. Thermal flexibilities of electric boilers and district heating network (DHN) are modelled and analysed, in which the flexibility of DHN is described by a detailed node-based quasi-dynamic model. The proposed scheduling method is to minimize the operation cost of IPHS. Case study is carried out on a typical IPHS with a 6-node power system and a 12-node DHS. Simulation results show that the scheduling method can reduce the operation cost of IPHS and improve wind accommodation.
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Ren, Hong Bo, Qiong Wu, Jian Yang, and Yin Yin Ban. "Optimum Siting and Sizing of Distributed Energy Resources Taking into Consideration Hourly Operating Strategies." Advanced Materials Research 953-954 (June 2014): 871–75. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.871.
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In this paper, a distributed energy resource (DER) system plan and evaluation model is extended to include the design of district heating network. In the model, production and consumption of electric power and heat, power transmissions, transport of fuels to the production plants, transport of water in the district heating pipelines and storage of heat are taken into account. The problem is formulated as a mixed integer linear programming (MILP) model where the objective is to minimize the overall cost of the DER system. The solution gives the DER structure, i.e., which production units, heat transport lines and storages should be built as well as their locations, together with design parameters for plants and pipelines.
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Bryszewska-Mazurek, Anna, and Wojciech Mazurek. "Cooperation of the Organic Rankine system with a cogeneration steam power plant - case study." E3S Web of Conferences 45 (2018): 00011. http://dx.doi.org/10.1051/e3sconf/20184500011.
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The cooperation of the ORC system with a cogeneration steam power plant has been considered. A district heating network is supplied from a bleeder turbine. An ORC system can utilize redundant heat, especially during the summer season, when only domestic hot water needs are served. The aim of the study was a selection of an extraction steam flow to produce the maximum electric power in an ORC system and also to cover the changing heating demand in the district heating network under consideration. Various values of extraction steam flows obtained from the bleeder turbine were considered. For a given extraction steam flow, the optimum ORC size has been adjusted. The average annual efficiency of the ORC was estimated at 0,12 (for the cyclic temperatures 120/35°C). The shortest simple payback time has been estimated at 4 years, assuming that heat from the bleeder turbine meats the heating demand throughout the year and thus the ORC system also operates throughout the year.
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Li, Ke, Ning Zhou, Lei Wang, Qian He, Hui Quan Zou, and Wei Huang. "A Customer-Focused Electricity Bill Pay Points Siting Model." Advanced Materials Research 588-589 (November 2012): 2064–68. http://dx.doi.org/10.4028/www.scientific.net/amr.588-589.2064.
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In order to solve the electricity bill pay points siting problem for electric power corporation, this paper proposes a hybrid model to optimize the siting of pay points and improve customers’ satisfaction. Different from traditional methods, customer density, queueing time and satisfaction degree, transportation and other factors are all taken into consideration in this model. Finally, a “10-minute electricity bill pay network” is constructed in Zhengdong new district with the application of the model proposed by this paper.
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Sudarmojo, Yanu Prapto. "Optimization of Placement and Size of Distribution Generators Using Quantum Genetic Algorithms to Improve Power Quality in Bali Distribution Networks." Journal of Electrical, Electronics and Informatics 3, no. 1 (June 18, 2019): 1. http://dx.doi.org/10.24843/jeei.2019.v03.i01.p01.
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World energy requirement increased significantly, the main energy source from an oil is very limited. This problem drive an enhancement develop which support small scale generator to be connected near distributed network or near load center. Distributed Generator (DG) is a power plant which have a little capacity range between 15 kW to 10 MW. Basically, DG instalation is one way to fix a voltage profile where an installed DG would inject voltage to a transmission system or electric power distribution.
Bali is a tourism area which it’s electric power source got a supply from Java and some large scale plant which use fuel of oil and gas, which until now still needed more of electric energy. An addition small scale generator for Bali is very helpful where economic profit is distribution cost and transmission cost’s reduction, electric cost and saving fuel energy. Technically a distributor of DG must be done correctly and optimal from it’s size or location so that give a maximum result from economic side, minimalizing electricity loss and increase voltage profile which result an electric power quality is improved. For that, in this research will use heuristic optimation with use Quantum Genetic Alghorithm method to placing distributed generator to Bali Electricity Network. To counting electicity loss and voltage profile, a method which used to solve it is Newton Raphson method.
The result of this research, DG is installed to feeder which plaed in Abang Sub-District, Karangasem District where Abang Feeder had a total 43a bus which is a part from Bali Distribution System. With using QGA, DG is installed to bus 1, 5, 7, and 302 with each DG capacity is 0,374 MW, 1,894 MW, 1,988 MW and 0,500 MW, after installment of DG, voltage profile can be fixed. Voltage profile for some bus to Abang Feeder could be fixed from 0,83 pu to 0,98 pu. Electricity loss from 1,105 MW become 0,234 MW.
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Cappiello, Francesco Liberato, Luca Cimmino, Marialuisa Napolitano, and Maria Vicidomini. "Thermoeconomic Analysis of Biomethane Production Plants: A Dynamic Approach." Sustainability 14, no. 10 (May 10, 2022): 5744. http://dx.doi.org/10.3390/su14105744.
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This work analyses the two most diffused technologies for biogas upgrading, namely water scrubbing and membrane separation. In order to carry out such analysis, these two technologies are coupled with photovoltaic panels and an electric energy storage system. The optimal water scrubbing renewable plant achieves a primary energy saving of 5.22 GWh/year and an operating cost saving of 488 k€/year, resulting in the best plant. It was compared to a reference system based on a cogenerator unit, directly supplied by biogas, producing thermal and electric energy, and delivered to the district heating network and to the electric grid. The profitability of both plants depends on the electric energy and biomethane exporting price. The proposed bigas upgrading plant achieves a payback period lower than 10 years with a biomethane selling price greater than 0.55 €/Sm3 and a primary energy saving index around 25–30% with a null share of thermal energy exported by the cogeneration plant.
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Li, Wei, Yi Huang, and Fang Min Wang. "Research on Sitting Transformer Substations in Rural Areas Based on Improved Genetic Algorithm." Applied Mechanics and Materials 490-491 (January 2014): 1652–56. http://dx.doi.org/10.4028/www.scientific.net/amm.490-491.1652.
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The process of urbanization, Beijing faces a number of environmental problems. Especially in the last few years, there has been constantly sustained fog and haze, which makes the implementation of electric heating in rural areas gradually on the agenda. After the implementation of electric heating, the irrationality of the regional power grid layout will be further amplified. With the rapid growth of electricity load in the planning area, the requirement of the power supply grid reliability and power quality is also increasing. Therefore, on the basis of power load forecasting in consideration of the the electric heating, and based on the particularity of rural power network, we achieve the Huairou District substation site with the use of improved genetic algorithm. The results can provide reference for the selection of substation of the whole Beijing rural area.
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Zhang, Lin Hua, Dong Yang, Ting Ting Chen, Shou Jun Zhou, and Ling Liu. "The Optimization Analysis of Hydraulic Junction Location of Three-Sources Branched Heat-Supply Network." Applied Mechanics and Materials 638-640 (September 2014): 2101–5. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.2101.
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In this paper, we shall first briefly introduce the hydraulic junction of three-sources branched heat-supply network and the related optimization method. It's difficult to guarantee that the system runs in optimal state and it increases energy consumption in the system. In view of this situation this paper proposes a method to find the optimal positions of hydraulic intersections based on analyzing a real heating system with three heat sources in Jining. The optimization objective is to minimize the electric power consumption of circulating water pumps in district heating system. Finally, optimization programs are designed and the optimized results verify the feasibility and validity of the method compared with conventional experience values.
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Hu, Xinghua, Yanshi Cao, Tao Peng, Runze Gao, and Gao Dai. "Nonlinear Influence Model of Built Environment of Residential Area on Electric Vehicle Miles Traveled." World Electric Vehicle Journal 12, no. 4 (November 19, 2021): 247. http://dx.doi.org/10.3390/wevj12040247.
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In this study, gradient boosting decision tree (GBDT) and ordinary least squares (OLS) models were constructed to systematically ascertain the influencing factors and electric vehicle (EV) use action laws from the perspective of travelers. The use intensity of EVs was represented by electric vehicle miles traveled (eVMT); variables such as the charging time, travel preference, and annual income were used to describe the travel characteristics. Seven variables, including distance to the nearest business district, road density, public transport service level, and land use mix were extracted from different dimensions to describe the built environment, explore the influence of the travel behavior mode and built environment on EV use. From the eVMT survey data, points of interest (POI) data, urban road network data, and other heterogeneous data from Chongqing, an empirical analysis of EV usage intensity was conducted. The results indicated that the deviation of the GBDT model (9.62%) was 11.72% lower than that of the OLS model (21.34%). The charging time was the most significant factor influencing the service intensity of EVs (18.37%). The charging pile density (15.24%), EV preference (11.52%), and distance to the nearest business district (10.28%) also exerted a significant influence.
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Hirijanto, Hirijanto, I. Wayan Mundra, and Bambang Wedyantadji. "INFILTRATION WELLS ALTERNATIVES TO REDUCE WATER PUDDLE IN LOWOKWARU DISTRICT, MALANG CITY." Journal of Sustainable Technology and Applied Science (JSTAS) 2, no. 1 (May 21, 2021): 1–8. http://dx.doi.org/10.36040/jstas.v2i1.3018.
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Surface waters give a plentiful supply of waters ready to be utilized for residence, farmland, fishery, industry, and electric generating machine, and most importantly, to deal with the problem of water scarcity (crisis). Rain is one of the hydrological cycles that help to preserve groundwater (shallow groundwater). During the rainy season, most waters go directly to the river and the sea without processing, creating inundations and flood in some places. Water resources, however, begin to lose their supporting capacity. Water supply is no longer balanced with the demand that starts to bulge up excessively. This disrupted balance is indicated by many critical lands that are less productive and incapable of absorbing waters to the ground. Considering this outline, the implementation of environmentally friendly infiltration wells can be a strategic option to solve the water balance issue. Some alternatives of infiltration wells are proposed as the solution to the problem that this research deals with. It is estimated that these wells can reduce 10%-15% of surface runoff rate in Lowokwaru District of Malang City, especially around Soekarno-Hatta Street that always leaves massive water puddle, especially during the rainy season. This research gives the relevant institutions and user community information about drainage construction, drainage network, and land use above drainage network. Through this information, it is expected that the follow-up can be given efficiently to produce an optimum and effective drainage network. Community participation, therefore, is needed to maintain the benefits of alternative infiltration wells to ensure their sustainability in the future.
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Maccarini, Alessandro, Enrico Prataviera, Angelo Zarrella, and Alireza Afshari. "Development of a Modelica-based simplified building model for district energy simulations." Journal of Physics: Conference Series 2042, no. 1 (November 1, 2021): 012078. http://dx.doi.org/10.1088/1742-6596/2042/1/012078.
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Abstract Urban Building Energy Simulation (UBES) is an efficient tool to investigate and subsequently reduce energy demand of urban areas. Nevertheless, UBES has always been a challenging task due the trade-off between accuracy, computational speed and parametrization. In order to reduce these computation and parameterization requirements, model reduction and simplification methods aim at representing building behaviour with an acceptable accuracy, but using less equations and input parameters. This paper presents the development and validation results of a simplified urban simulation model based on the ISO 13790 Standard and written in the Modelica language. The model describes the thermo-physical behaviour of buildings by means of an equivalent electric network consisting of five resistances and one capacitance. The validation of the model was carried out using four cases of the ANSI/ASHRAE Standard 140. In general, the model shows good accuracy and the validation provided values within the acceptable ranges.
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Vannoni, Alberto, Alessandro Sorce, Alberto Traverso, and Aristide Fausto Massardo. "Techno-Economic Analysis of Power-to-Heat Systems." E3S Web of Conferences 238 (2021): 03003. http://dx.doi.org/10.1051/e3sconf/202123803003.
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The heating and cooling sector, responsible for a large fraction of greenhouse emissions, may have a large scale impact on the energy system evolution contributing to smart industrial and domestic electrification; at the same time the recent increase of renewable energy sources installation, posing a threat in terms of grid stability, makes available a considerable amount of clean and cheap electrical energy during peak hours production. Power to heat technologies constitute a promising solution to face both these issues reducing the electric demand variability and decarbonizing the heat production. Large vapor compression heat pumps are a reliable technology able to compete, under the economic point of view, with the heat-only-boilers in order to serve district heating networks. Performance and economic profitability of a compression cycle is strongly dependent on available thermal source and the temperature of water delivered to the network. The present work explores and compares performance and economic indicators under different installation conditions, considering compression heat pumps employing four different fluids: a traditional HCF (R134a) and three natural fluids, ammonia (R717), butane (R600), and propane (R290), often preferred nowadays to HCFs due to the lower global warming potential.
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Li, Wei, Mengjun Li, Ning Zhang, Xuesong Zhou, Jiegui Zhou, and Guanyu Song. "Optimizing Allocation of Distributed Electric Heating for Large-Scale Access Distribution Considering the Influence of Power Quality." Energies 15, no. 10 (May 13, 2022): 3587. http://dx.doi.org/10.3390/en15103587.
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In this paper, a dual-layer grid comprehensive resource optimizing allocation model is proposed, which considers power quality controlling and load optimization scheduling under large-scale application of distributed electric heating. The upper-layer planning aims to minimize the active power loss of the distribution network, the minimum voltage deviation, and the minimum investment cost of the power quality control device. The capacity configuration of the management device and the number and location of the commutation switch configuration were determined. The lower layer is load optimization scheduling, with the minimum number of action switches and the minimum three-phase imbalance as the planning goals, and the decision variable is the state of the commutation switch. By co-simulation through Matlab and OpenDSS, the improved particle swarm algorithm and genetic algorithm are used for multi-objective optimization and the solution. In this way, the capacity configuration of reactive power compensation and active filter, as well as the installation position and switch state of the commutation switch are optimized and managed. Finally, taking the rural low-voltage distribution network in the Tongzhou District as an example, simulations considering the variation in the distributed electric heating penetration rate in the range of 20–80% are carried out. The calculation example results show that the proposed algorithm is effective, can effectively improve the power factor, reduces the harmonic content of the distribution network and the three-phase unbalance, and significantly improves the distribution network voltage.
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Rosato, Antonio, Antonio Ciervo, Giovanni Ciampi, Michelangelo Scorpio, and Sergio Sibilio. "Integration of Micro-Cogeneration Units and Electric Storages into a Micro-Scale Residential Solar District Heating System Operating with a Seasonal Thermal Storage." Energies 13, no. 20 (October 19, 2020): 5456. http://dx.doi.org/10.3390/en13205456.
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A micro-scale district heating network based on the operation of solar thermal collectors coupled to a long-term borehole thermal storage is modeled, simulated and investigated over a period of five years. The plant is devoted to covering the domestic hot water and space heating demands of a district composed of six typical residential buildings located in Naples (southern Italy). Three alternative natural gas-fueled back-up auxiliary systems (condensing boiler and two different technologies of micro-cogeneration) aiming at balancing the solar energy intermittency are investigated. The utilization of electric storages in combination with the cogeneration systems is also considered with the aim of improving the self-consumption of cogenerated electric energy; heat recovery from the distribution circuit is also evaluated to pre-heat the mains water for domestic hot water production. The performances of the proposed plant schemes are contrasted with those of a typical Italian decentralized heating plant (based on the utilization of natural gas-fueled non-condensing boilers). The comparison highlighted that the proposed configurations can decrease the primary energy consumption (up to 11.3%), the equivalent emissions of carbon dioxide (up to 11.3%), and the operation costs (up to 14.3%), together with an acceptable simple pay-back period (about 4.4 years).
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Buffo, Giulio, Domenico Ferrero, Massimo Santarelli, and Andrea Lanzini. "Reversible Solid Oxide Cell (ReSOC) as flexible polygeneration plant integrated with CO2 capture and reuse." E3S Web of Conferences 113 (2019): 02009. http://dx.doi.org/10.1051/e3sconf/201911302009.
Full textAbstract:
This work presents the concept of a Reversible Solid Oxide Cell (ReSOC) system localized in an urban residential district. The system is operated as a polygeneration plant that acts as interface between the electricity grid and the local micro-grid of the district. The ReSOC plant produces hydrogen via electrolysis during periods of low electricity demand (i.e., low-priced electricity). Hydrogen is used for multiple city needs: public mobility (H2 bus fleet), electricity production delivered to the micro-grid during peak-demand hours, and heat (accumulated in a storage) provided to the local district heating (DH) network. An additional option analyzed is the use of part of the H2 to produce DME using CO2 captured from biogas obtained from municipal solid wastes. The DME is used for fueling a fleet of trucks for the garbage collection in the residential district. A traditional CO2 removal process based on liquid MEA thermally integrated with the ReSOC system is studied. A time-resolved model interfaces the steady-state operating points with the thermal storage and the loads (electrical, H2 buses, DME trucks, heat), implementing constraints of thermal and H2 self-sufficiency on the system. Neglecting the DME option, the average daily roundtrip electric efficiency is about 38%, while the annual efficiency, which includes H2 mobility and thermal energy to DH, reaches 68%. When the DME option is considered, the thermal demand for CO2 removal and conversion process reduces the heat availability for DH, while the need for additional H2 for DME synthesis increases the electricity consumption for water electrolysis: both these phenomena imply a reduction of system efficiency (-9%) proportional to DME demand.
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Roselli, Carlo, Elisa Marrasso, and Maurizio Sasso. "Gas Engine-Driven Heat Pumps for Small-Scale Applications: State-of-the-Art and Future Perspectives." Energies 14, no. 16 (August 9, 2021): 4845. http://dx.doi.org/10.3390/en14164845.
Full textAbstract:
Gas engine-driven heat pumps are an interesting option to satisfy space heating and cooling demands aiming at energy saving, environmental impact and operating costs’ reduction. This work presents (i) a comprehensive review updated on gas engine-driven heat pumps research activities, (ii) the investigation of the central role of this technology in the air conditioning sector and (iii) the future perspectives regarding gas engine heat pumps’ diffusion in the context of the energy sector decarbonisation. The outcomes highlight that gas engine heat pumps could have better environmental performance compared to electric heat pumps both in heating and cooling operations. Moreover, they could play a pivotal role in the fight against climate change and energy security since they can guarantee an energy mix differentiation moving from electricity to natural gas and renewable gases’ usage. Indeed, by 2030, a lower-carbon gas grid could be supported by renewable gases. A further investigation has concerned diffusion of gas heat pumps activated from biofuels produced by local biomass in an energy community scenario based on a low-temperature energy district network. A novel biomass-based GEHP interacting with a low-temperature district heating network is proposed here. This system could save more than 30% of primary energy compared to biomass-fuelled boilers.
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Walelign, Wondmeneh Getnet, Jemal Yousuf Hassen, and Endalew Getnet Walelign. "The Role of ICT in Utilization of Teff Technologies in Enebsie Sar Midir District, East Gojjam Zone, Ethiopia." International Journal of ICT Research in Africa and the Middle East 5, no. 1 (January 2016): 1–14. http://dx.doi.org/10.4018/ijictrame.2016010101.
Full textAbstract:
This study was intended to assess the role of ICTs in utilization of teff technologies in Enebsie Sar Midir district. Simple random sampling procedure was used to select three kebeles and 136 households. Questionnaire and observation were used to collect data. Descriptive statistics like mean, percentage and frequency and univariate analysis such as t-test and chi-square tests and binary logistic regression model were used to analyze the data. Network interruption, language problem and usage difficulty were among the challenges not to use mobile phone. Interruption of electric power and information being not area specific were some challenges not to use radio and television for teff technologies. Construction of infrastructures, provision of adult education and trainings for farmers, introduction of Amharic language enabled mobile phones is very useful for increasing information and communication technologies use in teff technologies and hence increase teff production.