Optimal Power Supply Research Articles

Analysis of smart grid power flow system with Gauss-Seidel method

The use of smart grid systems is a good opportunity for the future of electric energy resilience in the future. The design of smart grid systems that use electrical energy sources through the PLN (National Power Plant), PV Solar System and Battery as a backup can improve efficiency in the electricity grid. To ensure that the system is feasible, it is necessary to analyze the power flow in the system. The analysis is performed on each case contained in the network with Gauss-Seidel Method. The analysis shows that case 1 is the most optimal power supply from PLN and RE (Renewable Energy).

Techno-economics of solar PV array-based hybrid systems for powering telecom towers

An attempt has been made to evaluate the financial feasibility of hybrid power supply option during real-time grid power unavailability (continuous and intermittent) conditions and determine the optimal hybrid power supply configurations for outdoor telecom towers in India. As grid power availability is highly dependent on locations, a review of real-time hourly grid power supply availability for telecom towers at 36 locations in different parts of India has also been presented. Ten different locations across different climatic zones were analyzed, and it was found that duration and continuity (continuous and intermittent) of power outages considerably affect the LCOE of different configurations. So it is imperative that these factors be taken into account when determining the optimal hybrid power system. Solar PV-based hybrid power supply systems were found to have lower LCOE for all power outage conditions both in continuous as well as intermittent with their values in the range of Indian rupees (INR) 6.76–INR 26.32 (US $0.095–US $0.371) per kWh for the optimal cases (1 US$ = INR 76.28 (As on April 27, 2020)). While solar PV with battery is found to be the least cost hybrid power supply options for the telecom towers located in areas with continuous grid power unavailability up to 4 h, a diesel generator also needs to be included for larger hours of continuous grid unavailability.

Grid-connected Micro-grid Power Supply and Distribution Transformer Capacity Optimization System Design in the Electricity Sales Environment

With the current gradual opening of our country’s electricity sales market and the successive improvement of related policies for grid-connected micro-grids, grid-connected micro-grid power supplies and their distribution transformer capacity have received attention and development. Based on the good development of my country’s electricity sales market environment, this paper designs the grid-connected microgrid power supply optimization system and its distribution and conversion capabilities to optimize the quality of electricity sales and optimize the grid configuration. In view of the fact that the operation of the microgrid system in my country’s market environment is more flexible at this stage, after a long time simulation test, a simulation analysis of the operation status of the grid-connected microgrid is carried out. In the course of the experiment, the electricity price in the distribution point process and the real-time changes of the electricity purchase price in the market will be considered comprehensively, and the processing in the micro-electricity system based on its distribution transformer capacity optimization system and the load forecast result will be considered. This article uses a power grid project actually constructed in East China as an example to analyze the results of simulation calculations. Then the NSGA-II algorithm is used to solve the optimized model for the cost and benefit composition of the grid. The optimized configuration method of the optical storage microgrid proposed in this paper can ensure the reliable power supply of users’ important loads during the off-grid operation of the microgrid, increase the installed capacity of distributed photovoltaics, and the configured energy storage system also allows enterprises to achieve low electricity prices. Purchase electric energy at any time and use it to supplement the load’s demand for electric energy during peak electricity price periods, thereby increasing revenue. The experimental research results show that the design of the grid-connected microgrid power supply capacity optimization system under the electricity sales environment studied in this paper can effectively reduce the additional investment required by external loads and the capacity of optical storage and distribution transformers. Only then can the economic marketing profit of the microgrid be improved to a certain extent.

Optimal energy management of a DC power traction system in an urban electric railway network with dogleg method

ABSTRACT Today, due to the several benefits of using the subway as a clean transportation system and also its expansion in many cities around the world, electrification to urban and suburban railway systems is experiencing a very important development procedure. Optimal power supply and management of energy that is economically viable is one of the important issues in the design of such systems. In this paper, in order to provide an optimal energy management and to determine the location of rectifier substations (RSs), and also to calculate power supply capacity (PSC) of the traction units, an optimal design and simulation of a DC railway traction power supply system (RTPSS) in urban area is proposed. In this regard, first, the structure of power system of RSs used in urban area is presented and analyzed in detail. Then, considering the importance of the standard criteria in designing the dynamics of a city’s RTPSS, an equivalent circuit for the desired network is provided. After defining the governing equations of the network and using the dogleg optimization method, to ensure convergence, the speed of solving equations is improved. In this study, in order to verify the performance of the presented method, the cost-based convergence characteristic curve for Dogleg optimization method is compared to the particle swarm optimization (PSO) approach. In order to confirm the robustness, applicability, and superiority of the proposed approach for optimal design and energy management in a city railway power system, the presented method is applied to a real study case. The obtained results through the simulation approve the effectiveness of using the Dogleg optimization method in power consumption by approximately 255 kWh in reducing energy compared to the practical energy consumption for one train during the trip in normal condition.

Вибір системи живлення низьковольтних однофазних електроприймачів повітряних ліній напругою 220/380 В

Two-phase three-wire and single-phase two-wire branches from main three-phase lines are integral components of three-phase four-wire systems. Therefore, the aim of this work is to choose the optimal power supply system for single-phase electrical receivers depending on their power and branch length. The comparison of single-, two- and three-phase power supply systems of single-phase electric receivers is carried out and analytical expressions are obtained to determine power losses, phase voltage loss and wire cross section for allowable voltage loss at the same total active load power and its equal distribution between phases. Based on the obtained expressions, the total power losses, voltage loss in phase and neutral wires for different power supply systems are analyzed. In the transition from a three-phase four-wire power supply system of single-phase electric receivers to a single-phase two-wire or two-phase three-wire system with the same total load power and equal load phases with wire cross sections selected for allowable voltage loss, power loss and phase voltage with a corresponding decrease in their active resistance. It is shown that in some cases the use of single-phase and two-phase branches saves conductive materials in comparison with the three-phase linear branch, the cross section of which is inflated due to the need to ensure the condition of mechanical strength. The dependences of the limiting length of three-phase and single-phase overhead insulated lines, which corresponds to the allowable voltage loss, on the active load power are calculated. It is shown that the limiting length of three-phase linear branches significantly exceeds the limiting lengths of single-phase and two-phase branches at the same load power. The optimal version of the power supply system should be selected on the basis of technical and economic calculation depending on the load capacity, line length and allowable voltage loss.

Low-carbon transformation of the regional electric power supply structure in China: A scenario analysis based on a bottom-up model with resource endowment constraints

The electric power industry is the main source of carbon emissions in China. The structural transformation of electric power supply plays a key role in the realization of low-carbon development in China. However, the low-carbon transformation of the electric power structure has to consider the differences in resource endowment and technical conditions among regions. To investigate the potential evolution of the regional electric power supply structure, we collect data of provincial resource endowment and technical differences and introduce them into the Integrated MARKAL-EFOM System (TIMES) model of China's regional electric power sector. In this model, different scenarios for carbon emission reduction in the electric power industry are set, and the optimal regional electric power supply structures under each constraint of carbon emissions are calculated. The results show that the electric power supply structure will change in various regions when the carbon emission reduction target increases from 5% (LC1 scenario) to 15% (LC3 scenario). In 2030, the proportion of thermal power in all regions will decline, especially in western China, where the proportion will decline by 8.47%. However, thermal power will still play a leading role in central China and eastern China, with the proportion more than 50%. Meanwhile, the proportion of the power generation of renewable energy in all regions will increase rapidly in the LC3 scenario, especially in western China, where the proportion will account for 60.72% in 2030, while the proportion will account for 27.26% in eastern China in 2030. Wind power will play an important role in the power supply system in the LC3 scenario, and the proportion of wind power in all regions will exceed that of solar power in 2030, especially in northeast China, where the highest proportion of wind power will come to 30.37%.

A Study On The Safety And Parameters Of Power Direct Led Lamp

As energy problems emerge, high-efficiency lighting devices that can replace conventional lighting are required to save energy, and among them, LED (light emitting diode) lighting has begun to emerge as the next-generation lighting. Since LED has low power, high efficiency, long lifetime, and fast response speed, it is suitable to replace existing lighting such as incandescent lamps, fluorescent lamps, and halogen lamps. The present study proposes safety of household appliances to prevent a degraded replacement effect due to excessive luminous flux of an LED lamp that replaces a bending-type fluorescent lamp (FPL), to prevent excessive design investment for manufacturers by providing appropriate optical reference values, to identify safety issues during the installation of AC power direct LED lamps, and to standardize the optimal power supply method that can be fixed by using the LED lamp based on external converters and the LED lamp for fluorescent lamp replacement.

Cost of avoided carbon: Optimizing power supply in southern India

Southern India houses over 49% of the total renewable energy capacity in India. This paper analyses the power supply situation in this region for year 2018 to evaluate the impact of renewable energy policies on energy costs and the resulting cost of avoided carbon. An optimisation model is built using GAMS. Model results show that the cost of absorbing renewable energy due to the “must run” policy for solar and wind energy plants ranges from $1.9/tCO2 to $4.5/tCO2 across states in the region, over and above the carbon tax of $5/tCO2 levied on all electricity consumers in India through the coal cess. ‘Must run’ status implies that the evacuation of power from solar and wind power plants should not be curtailed for factors other than grid or equipment safety. The total additional cost due this policy ranges from $200 to $350 million/year. Inter-regional transfer of renewable energy after meeting the mandated renewable purchase obligations in the region, is suggested as one possible route to reduce the financial burden on distribution utilities. This would reduce the unit cost of energy by about 1–7% across the states. Validating the model results against actual data for the year 2018 suggests that regulatory constraints and policy interventions have reduced the solution space for reasonable cost-based optimisation in Southern India.

Optimal sizing and operation for microgrid with renewable energy considering two types demand response

The integration of renewable energy sources into the power grid poses several challenges due to their variability in output power as they primarily depend on weather conditions. As a countermeasure, battery energy storage systems are introduced in order to mitigate output power fluctuations of the renewable energy sources. Moreover, demand response programs have been attracting huge attention as an effective mechanism for efficient energy management. It enables power suppliers to cope with the output uncertainty of renewable energy systems. First step, we propose an HRES design methodology that takes into account one year. In order to find the optimal power supply configuration, it is necessary to take into account the changes in load demand due to weather conditions and seasons for one year. However, the computational cost of simulating one year is huge and requires a rather long simulation time. Therefore, we propose a simplified simulation method that uses clustering to account for changes in load demand due to weather and seasonality in one year. Second, the first proposed method is used to propose a method for optimizing the HRES equipment capacity and operation schedule considering demand response. In this paper, mixed-integer linear programing is used as the optimization method. The proposed method considers two types of demand response and achieves cost reduction by controlling load demand in response to generated power fluctuations.

Economic Optimization of Electricity Generation and Sales in Microgrid System Based on PSO

In this paper, particle swarm optimization (PSO) is introduced to carry out economic optimization under the microgrid system, and the optimization dispatching problem of the microgrid system [1] is studied. Utilize the role of battery charging and discharging and power exchange of large power grids, with the goal of minimizing the cost of load power supply, and establishing the constraints of distributed power sources [2]. A mathematical model is established for the optimal scheduling problem under the microgrid system composed of wind, solar and storage batteries, and the PSO algorithm is used to solve the model, and the optimized power supply composition and operating cost are obtained, and an optimized scheduling scheme is given.

Comprehensive sizing and optimization method for series-hybrid unmanned convertiplane

This paper presents a novel sizing and optimization approach for the emerging series-hybrid unmanned convertiplane, which can be used to translate the top-level design requirements into the design parameters corresponding to the optimal power supply strategy and minimum total takeoff weight. The method comprehensively considers the design constraints in the rotor, fixed-wing, and transition modes, and pays special attention to the characteristic response of Series Hybrid Electric System (S-HES) in complex application scenarios, especially the coupling of battery power, energy, and state-of-charge under high-power discharge conditions, the variation of fuel economy, and the adjustment of power supply strategy. With proposed method, it’s possible to rapidly explore the design space in the initial design stage and find out the optimal design results with high confidence. A case study was proposed to verify the approach. The results reveal the particularity of convertiplane in terms of power requirements, and prove the necessity to consider detailed S-HES characteristic responses during parameter determination. The optimal design parameters were obtained through the hybrid control parameter optimization, which verified the effectiveness of proposed method. Possible errors and corresponding correction methods were also presented.

Study on Power Supply Structure of AC / DC Distribution Network Considering Different Proportion of New Energy Access

Considering the diversification of energy and load, according to the different situation of new energy access to distribution network, three typical AC-DC hybrid distribution network power supply modes are summarized. On the basis of these three power supply modes, the indexes of AC-DC hybrid distribution network are extracted, and the comprehensive evaluation index system is established. A comprehensive evaluation model of AC / DC hybrid distribution network suitable for new energy access is proposed, which aims to maximize economic benefits. The example shows that the optimal power supply mode can be selected through the evaluation model when the proportion of new energy is different, which can lay a foundation for the future distribution network to better serve users on the premise of distribution network profitability.

ШИРОКОСМУГОВІ АНТЕНИ НА ОСНОВІ КІЛЬЦЕВОЇ ГЕОМЕТРІЇ

В роботі розглянуто варіанти моделей квазіфрактальних кільцевих структур. Для їх синтезу запропонований векторний опис фрактальної трансформації окремих сегментів початкової геометричної форми. Поєднання декомпозиції геометричної форми та багатовимірного фрактального підходу дозволяє спростити синтез фрактальних 3D-структур та/або використовувати кілька видів фракталів, у тому числі, з різною кількістю ітерацій. Такий підхід дозволяє досягти широкосмуговості та багатодіапазонності антенних систем. При цьому досліджено вплив рівня сегментації та варіантів схеми живлення на просторово-частотні характеристики антени. Через складність опису взаємодії антен неевклідової геометрії з радіохвилями для їх синтезу та аналізу обрано методи чисельного моделювання. Для аналізу просторово-частотних характеристик проектованих антенних рішень використані такі показники, як зворотні втрати, діаграма спрямованості та коефіцієнт стоячої хвилі. Отримані оцінки відносної смуги пропускання δf = 0,9 свідчать про перспективність запропонованого підходу для реалізації антенних систем з високим рівнем широкосмуговості

The thermal model of winter aggregation of bees

For successful competition of the Russian beekeepers in the world honey market it is necessary to concentrate their attention on production of separate grades of this product. The most expensive honey is produced in spring and therefore it is necessary that the bees were successful in winter. The use of electric heating of bee hives does not always have a positive effect on the safety of bees in winter. In this regard, it is necessary to study more carefully the complex biological formation - winter bee hives. There were the basic equations for determining the physical parameters of the bee family in winter, including the energy characteristic. The established equations were included in the mathematical models describing the parameters of the microclimate. Mathematical processing of the obtained thermophysical model was carried out in the Comsol software product, which confirmed the validity of the use of the main functional dependencies and allowed to see the critical zones of the hive in temperature and humidity. Despite the large temperature changes outside the hive, it is maintained a fairly stable positive temperature at the level of +25°C to + 32°C inside. Such temperatures are not dangerous for bees. The images of temperature fields obtained in the course of mathematical processing confirm the assumptions that the lowest temperatures are in the lower part of the hive, and the higher ones are in the upper part. The results of the simulation will be used to determine the optimal power supply to electric heaters and to the place of their installation.

Design Optimization of Two-Quadrant High-Current Low-Voltage Power Supply

The high-current delivered by a dedicated power supply is the condicio sine qua non to obtain the strong magnetic field produced by superconducting magnets. The end goal of such power supply is to control the current, very precisely, across this distinctive kind of load. To this extent, the topology and a specific mode of operation that fit the requirements is analyzed and presented in this article. To obtain a contemporary power supply design, a design optimization of the overall system with respect to efficiency and volume is carried out. Considering the modularity specification, the system is split into elementary building blocks and one optimally designed unit is practically implemented and verified against predictions from the design tool. In sum, this article provides the comprehensive design process for a modern 2-quadrant high-current low-voltage dc/dc power supply.

Critical SCADA applications to parallel operation of transformers in railway electrical traction

The article describes the parallel operation of medium voltage (MV) transformers utilized in electric traction substations (ETS), their connection to the national power system (NPS), and the conditions required for the parallel operation of the ETS transformers. Solutions for the optimization of the parallel operation the MV transformers that power the electric railway traction system (ERTS) are discussed. In the case of multiple failure (fault transformers that serve a section) or load increase over the rated power provided by an electric traction substation (ETS), connection to the respective section of the adjacent ETS transformers is required. The parallel coupling of ETS is possible if High Power Transformers ERTS meet all the conditions for parallel operation. This mode of operation ensures the stability of the electricity distribution system for the consumer. SCADA systems can be used for monitoring critical situations and general optimization of electrical power supply of the railway electric traction system.

Towards Energy Efficient Load Balancing for Sustainable Green Wireless Networks Under Optimal Power Supply

The enormous growth in the cellular networks and ubiquitous wireless services has incurred momentous energy consumption, greenhouse gas (GHG) emissions and thereby, imposed a great challenge to the development of energy-efficient sustainable cellular networks. With the augmentation of harvesting renewable energy, cellular base stations (BSs) are progressively being powered by renewable energy sources (RES) to reduce the energy crisis, carbon contents, and its dependency on conventional grid supply. Thus, the combined utilization of renewable energy sources with the electrical grid system is proving to be a more realistic option for developing an energy-efficient as well as an eco-sustainable system in the context of green mobile communications. The ultimate objective of this work is to develop a traffic-aware grid-connected solar photovoltaic (PV) optimal power supply system endeavoring the remote radio head (RRH) enabled heterogeneous networks (HetNets) aiming to minimize grid energy consumption and carbon footprint while ensuring long-term energy sustainability and energy efficiency (EE). Moreover, the load balancing technique is implemented among collocated BSs for better resource blocks (RBs) utilization and thereafter, the performance of the system is compared with an existing cell zooming enabled cellular architecture for benchmarking. Besides, the techno-economic feasibility of the envisaged system has been extensively analyzed using HOMER optimization software considering the dynamic nature of solar generation profile and traffic arrival rate. Furthermore, a thorough investigation is conducted with the help of Monte-Carlo simulations to assess the wireless network performance in terms of throughput, spectral efficiency (SE), and energy efficiency as well under a wide range of design scenarios. The numerical outcomes demonstrate that the proposed grid-tied solar PV/battery system can achieve a significant reduction of grid power consumption yielding up to 54.8% and ensure prominent energy sustainability with the effective modeling of renewable energy harvesting.

Программное обеспечение для проектирования оптимальной сети высоковольтного электропитания космического аппарата

Программное обеспечение для проектирования оптимальной сети высоковольтного электропитания космического аппарата

Integration of Decentralized Generations into the Distribution Network- Smart Grid Downstream of the Meter

For several years now, public electric utilities have been turning to smart grid technology, on the one hand, to deal with power grid management and operation and to meet new consumer demands on the other. However, overcoming the integration constraints of intermittent and predictable renewable energy production remains one of the primary objectives of this action. It is within this framework, that we have developed a solution that involves implementing a smart grid system downstream of the meter that will scratch onto the smart grid of the network manager upstream of the meter to complete it and give it a lot of flexibility. This system called 'TAKATI' allows one to calculate the production forecasts of the renewable energy plants, to take charge of the load shedding priorities decided by the customer, to establish the optimal power supply scheme, to order the cut-off devices of the customer's internal installation for the execution of the optimal scheme, to communicate with the Distribution Network Manager (DNM), to ensure compliance with the DNM's directives with regard to active and reactive powers to be injected on the power grid by acting on the receivers and capacitors and responding to requests for deletion and making the necessary arrangements in such cases.

ОБОСНОВАНИЕ ГРАНИЦ ПРИМЕНЕНИЯ СИСТЕМ ЭНЕРГОСНАБЖЕНИЯ ДОЖДЕВАЛЬНЫХ МАШИН

Diff erent power supply systems with hydraulic, electric and mechanical drive are used in sprinklers for watering crops of the same type. Depending on the agrotechnical operating conditions of sprinklers, the systems diff er from each other in terms of energy and operating costs in 1.5…4.2 times. The paper considers a problem of choosing the optimal power supply system for a sprinkler unit working under specifi c conditions. The author has examined power supply systems for sprinklers: a hydraulic drive with a rotating hydraulic motor; a hydraulic drive with a reciprocating hydraulic motor; a mechanical drive; an electric drive powered by a cable line, an overhead line, a portable generator or accumulator batteries, which are all characterized by an individual resulting quality indicator. This indicator can be represented by any parameter of the system. Applying the theory of vector synthesis, he has chosen the effi ciency criterion as an indicator that takes into account the system parameters: specifi c power, energy losses, reliability indicator, operating costs, cost and mass of the system elements; as well as agrotechnical conditions: inlet pressure, distance from the water reservoir and centralized energy supply system, investments in sprinklers, irrigation rate, irrigation area and irrigation profi t. According to the effi ciency criterion, a graphical solution to the problem has been presented and it has been established that systems with an electric drive and various power sources are feasible for areas of more than 40 hectares, those with a hydraulic drive – for an irrigated area of less than 40 hectares, and those with a mechanical drive – less than 6 hectares.