bluuebunny/crossref_metadata_2025 huggingface dataset:
Electric Generators for Direct Coupled High Speed Turbo Generators in Distributed Power Systems
Authors: Vaidya Jay
Published: April 2022

This article addresses various technical challenges in developinghigh speed, lightweight electric generators for applications in directcoupled high speed generators for distributed power systems. Thesechallenges involve the technologies of electromagnetics, thermodynam-ics, rotor dynamics, and engineering assembly practices. How those chal-lenges are being addressed and the results of activities to date relating togenerators from several hundred kilowatts to a few megawatts will bediscussed. Current status and the test data relating to these generatorswill be presented.While the requirements of power and voltage levels as well as theduty cycle vary, the applicable generator technology is mainly impactedby the power level. The electric generator is typically driven by a highspeed turbine. The operating speeds of the turbine and the mechanicaland thermal interfaces with the generator have a substantial impact onthe design details of the generator.The best approach in interfacing the high speed turbine to the gen-erator is to directly couple the two by means of a mechanical couplingand exclude the need for gear, belt or other mechanical transmissionsystems. The high speed turbine operates most ef ficiently at their ratedspeed, which varies with rated power output. Thus while a typical 200kW turbine may operate at 60000 rpm, a MW class turbine may oper-ate in the range of 15000 rpm to 30000 rpm. It is often details such asthe coupling and mounting arrangement and the suitability of coolantsand lubricants that affect the generator design and impact the weight

and size of the final product. Selection of the appropriate generatortechnology is highly dependent on the operating speed requirements.Examples of speci fic power and speed ratings as well as suitability ofgenerator technologies such as permanent magnet (PM), wound rotorsynchronous, switched reluctance (SR) and induction will be discussed.Current development programs for 30 kW to 2.5 MW power generatorswill be presented
Landfill Gas as Fuel for Combined Heat and Power
Authors: Simon Ms. Sarah J. , Singleton Amanda R. , Carter John F.
Published: April 2022

When landfill gas (LFG) is used in combined heat and power(CHP) systems, the bene fits multiply. A CHP project powered by LFGnot only provides significantly better energy efficiency and cost savings,but it also achieves signi ficant environmental bene fits from using a lo-cally produced, biomass fuel.The U.S. Environmental Protection Agency (EPA), Land fill Meth-ane Outreach Program (LMOP) has supported the development of LFGenergy (LFGE) projects for more than a decade. The LMOP encouragesthe development of LFGE projects in several ways. To achieve moreLFG use, the program maintains voluntary partnerships with businesses,communities, and states. The LMOP provides information about LFGEopportunities in the United States and prepares preliminary feasibil-ity studies for land fills and potential LFG users. The LMOP and theLFGE industry have achieved signi ficant reductions in emissions ofgreenhouse gases, because LFG is approximately 50% methane andmethane traps more heat in the atmosphere than carbon dioxide, themost prevalent greenhouse gas. The collection and use of each ton ofLFG methane is equivalent to the reduction of over 20 tons of carbondioxide emissions.The LMOP maintains a land fill and LFGE project database (LMOPdatabase), which classifies 16 LFGE projects as CHP. These projects rangefrom a 120 kilowatt (kW) microturbine installation to a 12 megawatt(MW) cogeneration plantCHP LFGE projects can create additional environmental bene fitsby offsetting fossil-fuel-based electricity and steam or heating demands with a renewable fuel. In 2007, the existing CHP projects fueled by LFGwill result in greenhouse gas reductions equivalent to preventing the useof approximately 1.3 million barrels of oil.In addition, using the waste heat from LFG- fired generators in aCHP configuration can improve project financial results by as much as100%, increasing the feasibility of developing LFGE projects. LMOP of-fers real-world project experience and tools to overcome the barriers inCHP LFGE project development.
Implementation of CHP Plants: The Best Investment Possibilities In Hungary
Authors: Zsebik Albin
Published: April 2022

Cogeneration is a very important tool for saving primary energy,avoiding network losses, and reducing emissions, in particular green-house gases. In addition, ef ficient use of energy by cogeneration cancontribute positively to the security of a nation’s energy supply and tothe competitive situation in both the private and public sectors of theenergy market.For this reason, and because of Hungary’s electricity price struc-ture, companies with large electricity and heat consumption, or with thepossibility to sell electricity or heat, are considering the technical andeconomical bene fits of implementing local combined heat and power(CHP) plants to supply energy for their technology processes.This article introduces the Hungarian electricity price structure,and shows the results of a feasibility study for implementation of a CHPplant.
Dimensioning and Efficiency Evaluation of Hybrid Solar Systems for Energy Production
Authors: Elia Stefano , Tiberi Vincenzo
Published: April 2022

Hybrid panels (HY) for joint production of thermal and electricalenergy are available on the market. The main contribution of this workis to evaluate the performance of hybrid systems and to determine thefield of application. Mathematical models of panels are used to evalu-ate thermal and electrical behaviour. Software produced by the authorscalculates the energy production of these devices in several operatingsituations; a comparison to that of photovoltaic (PV) and thermal (TH)systems is performed. Moreover, the economic validity of such an invest-ment is evaluated. Finally, a simplified criterion has been developed tocalculate the best subdivision of the available deployment surface amongTH, PV and HY panels.
Permitting Procedures and Challenges of CHP Implementation
Authors: Carriere Jeanese L. , Kozman Theodore A. , Lee Jim
Published: April 2022

The objective of this research is to determine appropriate proce-dures required to apply for air permitting and interconnection agree-ments with all necessary agencies to assist an oilfield service company inLouisiana implementing a combined heat and power (CHP) system fortheir day-to-day operations. The main reasons for the facility to imple-ment CHP are twofold. The management wants to provide a climatecontrolled work environment for the facility personnel to ensure that ahigh level of productivity is achieved. The use of CHP will also reducethe greenhouse gases that are emitted into the atmosphere. The proce-dures required for air permitting and utility permitting are developed,followed by discussions on the challenges of implementing CHP inLouisiana. The development of a how-to guide on CHP implementationusing a case study will provide insight on the procedures for potentialCHP adopters in Louisiana.
Least-cost Paths to Energy Independence at a Midwestern University
Authors: DeBaillie Lee
Published: April 2022

In September of 2006, Wisconsin Governor Jim Doyle announcedthat four Wisconsin college campuses would be selected to participate ina pilot program to achieve energy independence by the year 2012. TheUniversity of Wisconsin River Falls campus was one of the sites selectedfor the program.Energy independence was defined as being “capable of acquiringor producing renewable energy equivalent to...consumption.”Wisconsin Public Power Incorporated contracted with the EnergyCenter of Wisconsin to identify and analyze the options for UW RiverFalls to achieve energy independence. Given the varied approaches andpotential combinations of strategies and technologies for reaching thegoal of energy independence, it was necessary to narrow them downto a manageable few. The narrowing process involved calculating thedegree of “independence” produced by each measure and the resultinglife cycle cost of implementing it. Energy independence was measuredas the percent of carbon-dioxide (CO 2) reduction from the energy con-sumption baseline. The final result shows the net present value cost (orsavings) of various paths to achieving energy independence.The Energy Center evaluated four scenarios to energy indepen-dence for UW River Falls. For each scenario we evaluated a combina-tion of measures, ranging from building efficiency and conservation tobiomass-fueled boiler plants.
Statistical Modeling of Steam Generation for Cogeneration in Indian Sugar Industry: A Case Study
Authors: Javalagi C.M. , Patil H.R. , Bhushi U.M.
Published: April 2022

The sugar industry is attaining new dimensions in the fast chang-ing world. It is poised to play a much higher and wider role. Per-formance and productivity of the sugar industry plays a vital role inattaining new dimensions. To be productive, sugar companies have towork as sugar complexes, producing sugar, ethanol, power and otherbyproducts. Cogeneration of power in the sugar industry is an importantsource of revenue. The conditions in India demand sugar industries togenerate and sell the electricity. This has created a new surge of interestamong the sugar mills for surplus power generation during the crushingseason using bagasse. This is possible and achievable only if the steamgeneration in the plant is increased and also the power and steam re-quirements of the plant are reduced. The study is aimed to relate variousparameters of bagasse, cane crushed to steam generation. Single factoranalysis of variance (ANOVA) is used to establish the significance ofeach parameter. Regression analysis is carried to establish the relationbetween parameters. The article arrives at a multiple regression equationrelating the steam generated as a function of its associated parametersviz. cane crushed, bagasse % of cane, moisture % of bagasse, pol % ofbagasse.
Distributed Generator Placement And Sizing in Unbalanced Radial Distribution System
Authors: Ramana Thiruveedula , Ganesh Vulasala , Sivanagaraju Sirigiri
Published: April 2022

To minimize power losses, it is important to determine the locationand size of local generators to be placed in unbalanced power distribu-tion systems. Because of some inherent features of unbalanced distribu-tion systems, such as radial structure, large number of nodes, and awide range of X/R ratios, the conventional techniques developed forthe transmission systems generally fail to determine optimum size andlocation for distributed generation (DG). This article presents a simplemethod for investigating the problem of contemporaneously choosingthe best location and capacity of DG in three-phase unbalanced radialdistribution systems (URDS) for power loss minimization and to im-prove the voltage profile of the system. The best DG location is deter-mined by using voltage index analysis, and capacity of DG is computedby a variational technique algorithm according to the available standardcapacity of DG. This article presents the results of simulations for 25-busand IEEE 37-bus unbalanced radial distribution system.
Commercial Buildings as Clean Domestic Energy Assets by 2025? DOE’s Roadmap for a Net-zero Energy Built Environment
Authors: Holuj Brian J.
Published: April 2022

A net-zero energy building (NZEB) is a highly energy-efficientresidential or commercial building that, over the course of a year, usesrenewable technology to produce as much energy as it consumes fromthe grid. In the commercial sector, building owners and tenants stand torealize attractive returns on their NZEB investments while reducing theircarbon footprints. Considering that buildings are our nation’s highestenergy-consuming and carbon-emitting sector, NZEBs have a vital rolein reducing U.S. energy demand and greenhouse gas emissions (GHGs).This article outlines the U.S. Department of Energy’s (DOE’s) goalsfor the energy use by our nation’s commercial buildings, the researchand development (R&D) efforts most critical to realizing NZEBs, andDOE’s strategy of collaborating with the private sector to speed the ar-rival of NZEBs in the marketplace.
Developing Solar Photovoltaic for Competitively Priced Energy
Authors: Hanzlik Rose A.
Published: April 2022

Parker Hannifin Corporation (“Parker”), in conjunction with Con-stellation Energy, investigated the possibility of developing a solar in-stallation at its New Britain (Connecticut) manufacturing facility. Parkereventually developed the project after carefully considering all of therelevant factors, which included not only the electricity price ($/kWh)comparison of solar with traditional brown power, but also future pricecurves, history of energy prices, and displacement cost with peak vs.blended price considerations.
Buying Down the Cost of Renewable Energy with Efficiency: Making Money by Saving Energy and the Environment
Authors: Thompson Mr. Patrick
Published: April 2022

Energy efficiency can play a major role in the long-term viability ofany building. The technology and practices are readily available to makea difference in both new and existing buildings. In most cases, the moreresources one consumes, the greater the opportunity for savings. If sav-ings are reinvested in new efficiency measures, the compounding effectover time can be dramatic. Further management practices can reduceoperations and maintenance (O&M) costs, ensuring that efficiency gainsare enhanced and maintained. Ultimately, the business becomes morecompetitive. “Buying Down the Cost of Renewable Energy” encouragesa successful business plan that not only is good for the environment butmakes sound financial sense. In fact, a practical and proven method isto start a revolving pool of funds with the savings from no-cost andlow-cost energy conservation measures. This pool is reinvested everyyear in increasingly more sophisticated efficiency projects. Eventually,the revolving savings pool becomes big enough to be the source of eq-uity investment; which facilitates the financing of larger projects suchas combined heat and power (CHP) and alternative energy plants. Suchmoney pool grows the same way a wisely managed investment portfoliodoes. The underlying discipline supports three key energy managementelements: (a) fiscal responsibility and financial management, (b) organi-zational learning and (c) plant modernization or innovation.
Performance Enhancement of Electrical Distribution Systems with Multiple Distributed Generation Sources
Authors: Sharma Manjunatha , Koppal Panduranga Vittal
Published: April 2022

The recent trends in electrical power distribution system operationand management are aimed at improving system conditions in order torender good service to the customer. Reforms in the distribution sectorhave given major scope for employment of distributed generation (DG)resources which will boost system performance. This article proposesa heuristic technique for allocation of multiple distribution generationsources in a distribution system. The allocation is determined based onoverall improvement in network performance parameters like reductionin system losses, improvement in voltage stability, improvement in volt-age profile. The hybrid of Genetic Algorithm with the proposed NetworkPerformance Enhancement Index (NPEI) along with the heuristic rulesfacilitates determination of feasible location for insertion of DG sources.A priority list is prepared with decreasing values of NPEI so that thedesigner can select most feasible locations. The developed approach istested with different test systems to ascertain its effectiveness.
Air Heating with Latent Heat Storage For Thermal Energy Management Of Solar Applications
Authors: Karthikeyan S. , Velraj Dr. R.
Published: April 2022

Renewable energy, particularly the solar energy, is gaining moreimportance worldwide for its clean, non polluting, inexhaustible andcost free nature. Though there are many applications possible, an im-portant factor is that solar energy is time dependant in nature. Hencethe commercial acceptance and the economics of solar thermal utilitiesor devices are tied to the design of an efficient thermal storage system tomeet the time-dependant supply and end use requirements. Latent heatthermal storage units have received greater attention in recent years,due to their isothermal behavior during the charging and dischargingprocesses, and higher energy storage density. In this study, an experi-mental investigation is performed to analyze the transient behavior of apacked bed latent heat storage unit, comprised of a cylindrical storagetank filled with Phase Change Material (PCM). PCM is encapsulated inspherical containers for thermal energy management and efficient utili-zation of solar energy. Applications include space heating and industrialdrying. Experimental results are reported and discussed.
Investigation of Developing Wave Energy Technology In the Gulf of Mexico
Authors: Guiberteau Kelly L. , Liu Yucheng , Lee Jim , Kozman Theodore A.
Published: April 2022

This article presents an investigative study on developing waveenergy technology in the Gulf of Mexico (GOM). The characteristics andconditions of GOM such as weather, wave climate, and activity of the oilindustry were assessed first for possible development of wave energy.The linear wave theory was then reviewed to identify methods to esti-mate wave power. Using wave data recorded from several stations in theGOM, methods used to estimate the wave energy were verified. Basedon the findings, the potential in the GOM for implementing wave energytechnology was confirmed. It is expected that the wave energy capturedfrom the GOM can provide a considerable portion of power required byoperating the oil platforms in that area.
Energy Sufficiency Arbitrage
Authors: Overturf Michael C. , Flynn Brian M.
Published: April 2022

Arbitrage is the exploitation of a commodity price differential intwo or more markets. Energy Sufficiency is an element of an energyportfolio that makes use of just-in-time electrical or thermal genera-tion or conversion. Energy Sufficiency Arbitrage requires the use of asufficiency-inclusive private energy portfolio, characterized by a non-zero Energy Index (ENDX™) [2].A sufficiency-inclusive energy portfolio for consumers of largeamounts of energy, specifically with high energy density (>70W/m2,for example), can be implemented using a private micro-grid, whichcreates a local energy market: a microgrid converts one form of energyinto a more useful one at a certain cost. Arbitrage pricing opportuni-ties are created in the pricing differential between microgrids andmacrogrids, with a resulting cost reduction, often significant, for theportfolio owner.We discuss in this paper how a Sufficiency Arbitrage advantagesare created and managed as part of the Sufficiency Kaizen continuousimprovement process [3].
Capturing Inherent Variability in Solar PV Energy through Realistic Estimates: A Case Study for the State of Minnesota
Authors: Vaidyanathan Dr. Mouli
Published: April 2022

Solar photovoltaic (PV) deployment in the United States and theworld is gaining accelerated momentum. It is very important for the solarPV industry standards to be realistic in its energy production estimates.The model of choice for most solar PV installers, enthusiasts and ownersis the use of National Renewable Energy Laboratory (NREL) PV Watts’simulation program. Through systematic analysis of multiple installationsin the State of Minnesota, real data are analyzed and compared to the PVWatt’s simulated results. It has been determined through this analysis thatPV Watts is aggressive, unattainable and misleads the public in its energyestimates for the State of Minnesota.It has also been discussed that to obtain more realistic solar PV en-ergy estimates, one must use of range of production rather than just onevalue. Giving one value for solar PV energy estimates has the tendencyto mislead because a low value estimate would make solar PV unattract-ive and a high value estimate will not be consistently attainable. Usingan average PV energy production is also deceptive, since by definition,half of the values are below and half are above the average. So, it’s im-perative to understand the statistical nature of available solar energy atany given time, which varies by the hour of the day and the season inthe year. Thus, through systematic analysis, a range of solar PV energyproduction estimate for the State of Minnesota is being presented whichis different and more accurate than NREL’s PV Watts.Other significant results summarized are the correlation betweenenergy production and precipitation, effects of tilt angles on energy pro-duction, summer and winter energy production, equipment related en-ergy production and string and microinverter effects on energy produc-tion.
Forecasting the Future of Alternative Energy Technologies Using Economic Payback Curves
Authors: Nowakowski Gary , Hahn Michael
Published: April 2022

Calculating a payback period for new or improved energy tech-nologies is a simple economic function. However, the very nature of itssimplicity tends to mask underlying dynamic characteristics that providevaluable insight into the interpretation of its results. Use of graphics toillustrate the payback function provides an expanded perspective on pay-back and its sensitivity to energy rates, product cost/pricing and efficien-cy/technology improvements. This article describes the use of paybackcurves and provides examples of how these curves can be utilized to gainan understanding of the natural evolution of both high-efficiency prod-ucts and renewable energy products; provide an indication on the sensi-tivity of product economics to energy prices, product cost, and efficiencyimprovements; and ultimately forecasts the future market prospects fornew or improved technologies and products based on economic merit.
Optimization of Hybrid Distributed Generation Systems For Rural Communities in Alaska
Authors: Willman Lindsay , Krarti Moncef
Published: April 2022

This article summarizes the results from a feasibility study to de-sign optimal distributed generation (DG) plants for three remote com-munities in Alaska. All three of these towns have isolated electrical gridsand currently rely on diesel fuel for 100% of their electricity and heatingrequirements. This assessment included an analysis of each communi-ty’s electrical and thermal load, a wind and solar resource evaluation,modeling and optimization of various DG systems using HOMER soft-ware, and an economic analysis of these systems. For all three of thecommunities, hybrid wind-diesel systems have the potential to providereductions in the cost of energy. However, the economic feasibility ofthese systems is extremely site-specific. In addition to providing possibledecreases in the cost of energy, these hybrid systems can also providesignificant environmental benefits, such as reductions in diesel fuel useand CO2 emissions. Future research should evaluate hybrid solar/windgenerators with combined-heat-and- power (CHP) diesel engines.
Performance Study of Distributed Generation System in Grid Connected/Isolated Modes
Authors: Nayak Sanjeev K , Gaonkar D.N. Gaonkar
Published: April 2022

The Microturbine Generations (MTG) system is becoming one of the promising sources of Distributed Generation (DG) due to their fuel flexibility, reliability and power quality. Thus, the accurate model of MTG system is required for the grid connected operation and its perturbations. This article presents the performance study of MTG based DG system in grid connected, islanding and re-closed modes of operation. The developed model of MTG system includes a microturbine as prime mover, Permanent Magnet Synchronous Machine (PMSM) and power electronics interacting circuit along with control schemes. The MTG system uses the turbine speed to control the microturbine output power in comparison with the reference speed and shaft speed. The generated AC power is converted to DC using a passive rectifier and this DC power is inverted back to AC power to mach grid frequency. The DC link power is delivered to the grid, islanding load using a three phase voltage source inverter with Pulse Width Modulation (PWM) techniques. While delivering the DC link power to the grid and islanding load, the respective Active, Reactive Power (PQ) and Voltage Frequency (VF) control strategies are used for inverter operation. The detailed model of MTG system along with control schemes is developed using Matlab/Simulink environment and the simulation results show the performance of MTG based DG system. From the simulation study, it is ascertained that, the developed model of MTG system can delivers the power to grid and isolated load significantly, by shifting the converter controller manually.
An Experimental Study of a Two-stage Thermoelectric Generator Using Heat Pipe in Vehicle Exhaust
Authors: Li Weizhong , Liu Changxin
Published: April 2022

Heat recovery from vehicle exhaust is a promising application of thermoelectric power generation (TEG). In our previous study, a single stage TEG with 4.04% system thermal efficiency has been tested. To improve the power output and the efficiency, a novel prototype two-stage TEG employing heat pipe from vehicle exhaust has been proposed. After system model being established, an experimental set up has also been built and tested for further study. Results of both theoretic analysis and experimental results show the viability of the prototype TEG for exhaust heat recovery. The prototype can gener-ate a maximum power of about 250W when the hot side operates at 473K. The system thermal efficiency reaches 5.37%; it is improved by 32% comparing to single stage TEGs 4.04% in the same operating conditions. Finally, system optimization and future improvement of the prototype are discussed.
Development and Computational Validation of an Improved Analytic Performance Model of the Hydroelectric Paddle Wheel
Authors: Liu Dr. Yucheng , Peymani Mr. Yoosef
Published: April 2022

This article presents an innovative analytical model to correctly evaluate the performance of a paddle wheel in generating electric-ity from moving fluid (water). The deficiencies of current analytical model in evaluating such performance are pointed out and overcome by the developed analytical algorithm. Important factors that affect the performance of paddle wheel, such as the drag force, relative velocity, efficiency curve of generator, are considered in the developed method. Next, computer simulations are performed. The computer simulation results agreed very well with the analytical results calculated following the presented approach. The presented analytical method and compu-tational techniques can be extended to estimate the performance of other hydroelectricity devices in the early design stage.
Fault Current Study of Inverter Interfaced Distributed Generators
Authors: Kong Xiangping , Zhang Zhe , Yin Xianggen
Published: April 2022

The fault current characteristics of inverter interfaced distributedgenerators (IIDGs) are very different from those of traditional synchro-nous generator. Prior to the fault current analysis of IIDG, a controlstrategy for low voltage ride-through (LVRT) of IIDG is proposed to meetthe grid code. Then the fault current characteristics of IIDG are analyzedbased on the study of dynamic responses of the inverter under conditionsof symmetric faults and asymmetric faults. Meanwhile, the analyticalexpressions of the fault current of IIDG are obtained. Finally, the fault cur-rent characteristics of IIDG are validated with simulation studies.
Voltage Stability Enhancement of Distribution System Using Network Reconfiguration in the Presence Of DG
Authors: Murthy G.V.K , Sivanagaraju S. , Satyanarayana S. , Hanumantharao B.
Published: April 2022

Voltage stability improvement is an important issue in powersystem planning and operation. This article presents the effect of re-configuration in the presence of distributed generation (DG) in radialdistribution system to improve the voltage stability with different loadmodels by using Artificial Bee Colony (ABC) algorithm. The analysisis accomplished using a voltage stability index which can be evaluatedat each node of the distribution system. The network reconfigurationinvolves a mechanism for selection of the best set of branches to beopened, one from each loop, such that the reconfigured radial distribu -tion system possesses desired performance characteristics. The locationof DG has the main effect of voltage stability on the system. Simulationstudy is conducted on 69-bus radial test system to verify the efficacy ofthe proposed method.
Optimum Tilt Angles for Manual Tracking of Photovoltaic Modules
Authors: Dutta Arindam , Biswas Jhumoor , Roychowdhury Soma , Neogi Subhasis
Published: April 2022

This article reports the investigation for the average optimal tiltangle of solar panels on a monthly basis (single axis tracking) for awide range of latitudes in the northern hemisphere to collect maximumtotal solar irradiation. Based on experimentally validated modeling, anew set of empirical relations has been proposed to compute the op -timum tilt angle on a monthly basis for the entire year. The accuracyof equations set is evaluated by standard statistical measures. Theproposed set of empirical equations is compared with an existing set ofempirical equations on various cities within the latitude and has yield -ed significantly better results. Solar Advisory Model (SAM) has beenused to compare—with respect to a fixed Solar Photo Voltaic (SPV)panel—the electricity predicted by (1) a new set of manual solar track-ing equations, (2) an established set of solar tracking equations, and (3)data from an automated single axis tracking system by a ProgrammableLogic Controller or PLC. It is found that, the manual tracking systembased on the proposed set of equations generates an annual averageincrease in electrical energy of (5-8)%, the old set of equation yieldsannual increase of (2-4)% and the PLC automated single axis trackingsystem generates a growth of (8-15)% over fixed SPV modules. Basedon the proposed empirical set of equation, a manual tracking systemhas also been designed and commissioned to reaffirm the justificationof the proposed equation set.
The Novel Fault Analysis Method of the Power Grid with Inverter Interfaced Distribution Generators
Authors: Yang Zengli , Wang Youhuai , Zhoug Hubing , Wang Linjun , Kong Xiangping , Zhang Zhe , Yin Xianggen , Xiao Fan
Published: April 2022

The special fault current characteristics of inverter interfaced dis -tribution generator (IIDG) make the conventional fault analysis methodbased on synchronous generator not applicable to a power grid withsuch IIDGs. In order to address this issue, according to the specialfault current characteristics of IIDG, the problems of conventional faultanalysis method when it is applied for the power grid with IIDGs arepointed out firstly. Based on it, a novel fault analysis method of thepower grid with IIDGs is proposed. Lots of simulation cases showthat the proposed fault analysis method has high calculation accuracy,which can meet the requirements of short-circuit calculation of thepower grid and setting calculation of relay protection.
Thermal Modeling of Indirect Solar Drying System: An Experimental Validation
Authors: Shukla S.K. , Srivastava A.K
Published: April 2022

The expressions for crop and moist air temperatures, drying rate and efficiency of indirect solar drying with phase change material (PCM) storage systems in quasi-steady state conditions have been derived. The analysis is based on the basic energy balance for the system. A computer model has been developed to predict the performance of the solar dry-ers. Experimental validation of the thermal model has been carried out by using modified heat transfer coefficients. Internal heat and mass transfer coefficients have been evaluated with PCM for March 24, 2014 in Varanasi, India. A fair agreement has been observed between theoretical and experimental results by using the modified internal heat and mass transfer coefficients.
Performance of a Hybrid Neural-Based Framework for Alternative Electricity Price Forecasting in the Smart Grid
Authors: Lei Gang , Xu Chunxiang , Chen Junmin , Zhao Hongyang , Parvaneh Hesam
Published: April 2022

Electricity forecasting is an essential task for energy management systemsof microgrids deployed in smart grids. Accurate price forecasting will eventuallyenhance the economic operation of microgrids. In this regard, theliterature is rich with studies focused on predicting electricity price datausing artificial neural networks. However, most of them consider a singlemodel such as multi-layer perceptron (MLP) and radial basis function (RBF)to perform electricity price forecasting. In this paper, a hybrid frameworkbased on simultaneously utilizing MLP-RBF neural networks is presented topredict the Iranian electricity market price. In addition, few works in literatureconsidered Iran’s electricity market as their case of analysis and investigation.Forecasting results indicate that MLP neural networks outperform theRBF neural networks. The values for the coefficient of determination (R)

corresponding to MLP and RBF neural networks are obtained 0.55 and 0.44,respectively. However, the proposed hybrid framework performed better thanboth MLP and RBF models with R-value equal to 0.71. In addition to this,the MSE and RMSE values show the superiority of the proposed method tothe single methods.
A Novel Predictive Control Scheme for Interleaved Buck Converter in Low Power Applications
Authors: Tirumalasetti Mahesh Babu , Manthati Udaya Bhasker , Srinivas Punna , Arunkumar C. R.
Published: April 2022

This paper presents a model predictive control (MPC) approach for Inter-leaved Buck Converter in low power applications. Traditional PI-based con-trol strategies have an arduous tuning process and can affect its performancewhen there are fluctuations in the operating point. Therefore, an MPC-basedcontrol strategy is proposed because of its simplicity, intuitiveness, easeof implementation, and inclusion of nonlinearities and constraints. Firstly,the model of Interleaved Buck Converter (IBC) is developed. Secondly, atwo-loop control strategy is developed with predictive inner current controland outer voltage control for DC link voltage regulation. In comparisonto traditional control strategies, the proposed one has a better dynamicresponse. Finally, simulation studies are done using MATLAB Simulink, and a prototype experimental setup is developed to validate the effectiveness ofthe proposed control strategy in the dSPACE1104 platform.
Optimal Voltage and Frequency Control in Solar Integrated Power Network
Authors: Kumar Vineet , Sharma Veena , Naresh R.
Published: April 2022

This study presents the modelling and simulation of a single area powersystem network containing three different generating sources, solar thermalpower plant (STPP), thermal, and diesel power plants. The simultaneousfrequency and voltage control problem has been investigated using LinearQuadratic Regulator (LQR) and State Feedback based Sliding Mode Control(SF-SMC) design. Also, the integration of Particle Swarm Optimization(PSO) has been considered for the selection of LQR cost function weightmatrices and SMC control parameters. Proper selection of LQR and SF-SMCparameters allows the controllers to handle the complexities involved in avery efficient manner and also augments necessary robustness in the con-troller design. The transient performance of the PSO based LQR and SF-SMCcontrolled system has been assessed in terms of time-domain performanceindices, and it has been compared with the conventional PID and 2-DOF PIDcontrollers. Additionally, the robustness of the proposed controllers has beentested and verified after contemplating variation in model parameters
Single Stage Power Control Strategy for Nanogrid Connected Solar PV System
Authors: Namani Rakesh , Natarajan Babu , Subramaniam Senthilkumar , Gurusamy Madhusudanan
Published: April 2022

The focus on reduction of converter size in nanogrid connected Photo-Voltaic(PV) systems increases to obtain the various advantages. This paper proposesa single stage nanogrid connected solar PV system that works with DC-ACinverter along with the closed loop control strategy to send the maximumpower from the PV array. The proposed scheme controls the power deliveryof the PV system to nanogrid in a single stage power conversion along withthe incorporated Maximum Power Point Tracking (MPPT) controller. Thedecoupled control strategy has been designed and developed for the proposedsystem using synchronous reference frame theory. The developed hardwareprototype in the laboratory has been used to validate MATLAB/Simulink sim-ulation results. The simulation and experimental results have been observed for dynamic changes in irradiation by maintaining the Total Harmonic Dis-tortion (THD) within the standard limits while operating at unity powerfactor. The successful validation of the proposed control strategy shows itsusefulness in real-time nanogrid applications.
Minimization of Circulating Currents in Parallel DC-DC Boost Converter Using Non-Linear Droop Control for Battery Energy Storage System
Authors: Chakrapani B. C. , Arunkumar C. R. , Srinivas Punna , Manthati Udaya Bhasker
Published: April 2022

Battery is considered the most dominant energy storage device for renewableenergy-based DC microgrid systems (RE-DCMG) because of its ability tostore energy for a longer duration. Here the power electronic converter playsa vital role, which acts as a bridge between the energy storage system and DCmicrogrid. One of the main reasons for the failure of battery systems due tothe failure of the power electronic converters. To improve the redundancy andconverter failure issues of battery energy storage systems (BESS), paralleloperation of multiple converters are required. However, the parallel operationfaces an issue of voltage imbalance between the converters which gives rise toan input circulating current. To address these issues, in this paper, we proposea nonlinear droop control based parallel DC-DC boost converter for battery energy storage system. The nonlinear droop control strategy ensures theequal battery current sharing between the parallel converters and good outputvoltage regulation. Moreover, SOC based controller avoids over-charging andover-discharging of the battery and the parallel converters ensure the redun-dancy in operation. The proposed system is designed and implemented in theMATLAB/Simulink and compared with the existing linear droop control.
A Novel Residential Energy Management System Based on Sequential Whale Optimization Algorithm and Fuzzy Logic
Authors: Nethravathi S. , Murali Venkatakirthiga
Published: April 2022

Demand side management has become inevitable in today’s smart gridenvironment to balance electricity supply and demand. Many methodolo-gies/algorithms have been developed for realizing and implementing thistechnique at different levels of distribution systems. Advanced meteringinfrastructure and the latest communication technologies have empow-ered residential consumers to participate in the demand side managementschemes. After careful investigations and analyses, the authors of this paperhave made a decisive effort to propose a novel sequential strategy for devel-oping an energy management system for scheduling loads of residentialconsumers. The proposed work aims at a fuzzy logic and an evolutionaryalgorithm-based approach of demand side management that considers theusers’ preference of operating time of the appliances at the residence of theirchoice, which has not been addressed earlier. This approach reduces the peakdemand and cuts the cost of electricity per billing period for a consumer. This study also encourages the consumers to install solar rooftop PV systemsby indicating the cost beneﬁts reaped over a more extended period. Theproposed framework is implemented in MATLAB, and the case studies provethe effectiveness of using this algorithm from the consumers’ perspective
Interoperability Issues and Challenges in 6G Networks
Authors: Kharche Shubhangi , Dere Prajakta
Published: April 2022

Interoperability allows seamless data exchange among the heterogeneous networks and is a crucial problem for the growth of forthcoming 6G networks. The research has focussed on the interoperability issues in the Internet of Things (IoT) related to cross-domain and cross-platform applications. However, the future 6G communication networks are not limited to interoperating with IoT. The 6G networks must interoperate with the Wearable IoT (WIoT), brain abstracted Internet of Thinking (IoTk), Internet of Everything, and other space and undersea networks. The network softwarization, slicing, and intelligentization techniques are envisioned to support seamless data exchange between 6G and other heterogeneous networks. However, to successfully achieve the goal of global 360∘∘ connectivity in 3D space, interoperability issues with heterogeneous services, applications, protocols, networks, etc., must be solved. The integration and interoperability of 6G networks with all aforementioned heterogeneous networks are inevitable to realize the goals of 3D communication successfully. The paper proposes a taxonomy to provide deep insights into interoperability issues, challenges, and possible solutions for 6G interoperability with WIoT, IoTk, IoE, and other networks. Though the techniques mentioned above in 6G networks will allow interoperable solutions, the integration and interoperability issues persist due to heterogeneities in high-frequency bands, base stations, technologies, device identities, protocols, and interfaces. The paper summarizes significant challenges regarding interoperability issues in various areas related to 6G and highlights the broad scope to further research.
The first cross-national study of adolescent young carers aged 15–17 in six European countries
Authors: Lewis Feylyn Mercedies , Becker Saul , Parkhouse Thomas , Joseph Stephen , Hlebec Valentina , Mrzel Maja , Brolin Rosita , Casu Giulia , Boccaletti Licia , Santini Sara , D’Amen Barbara , Socci Marco , Hoefman Renske , de Jong Nynke , Leu Agnes , Phelps Daniel , Guggiari Elena , Magnusson Lennart , Hanson Elizabeth
Published: April 2022

For the first time, this article will provide a cross-national profile of adolescents who provide unpaid care to their ill or disabled family members in six European countries with varied levels of awareness, policy and service provision regarding adolescent young carers. Utilising an online survey, 2,099 adolescent young carers were identified in Italy, the Netherlands, Slovenia, Sweden, Switzerland and the UK. This article focuses on the impact of unpaid care on their mental health, well-being, physical health and education. Their preferences for informal and formal support were also examined. These groundbreaking findings help promote a ‘rights’ approach to adolescent young carers, which can serve as a critical driver for supportive policy creation on both a country-specific and pan-European level.
Scattering loss in precision metrology due to mirror roughness
Authors: Drori Yehonathan , Eichholz Johannes , Edo Tega , Yamamoto Hiro , Enomoto Yutaro , Venugopalan Gautam , Arai Koji , Adhikari Rana X.
Published: April 2022

Optical losses degrade the sensitivity of laser interferometric
instruments. They reduce the number of signal photons and introduce
technical noise associated with diffuse light. In quantum-enhanced
metrology, they break the entanglement between correlated photons.
Such decoherence is one of the primary obstacles in achieving high
levels of quantum noise reduction in precision metrology. In this
work, we compare direct measurements of cavity and mirror losses in
the Caltech 40 m gravitational-wave detector prototype interferometer
with numerical estimates obtained from semi-analytic intra-cavity
wavefront simulations using mirror surface profile maps. We show a
unified approach to estimating the total loss in optical cavities
(such as the LIGO gravitational detectors) that will lead towards the
engineering of systems with minimum decoherence for quantum-enhanced
precision metrology.
Direct observation of terahertz topological valley transport
Authors: Hong Yu-Liang , Tang Gong-Hui , Peng Ru-Wen , Fan Ren-Hao , Ma Zhong-Li , Wang Zheng , Jiang Yue , Chen Le-Di , Wang Mu
Published: April 2022

Topological photonics offers the possibility of robust transport and efficiency enhancement of information processing. Terahertz (THz) devices, such as waveguides and beam splitters, are prone to reflection loss owing to their sensitivity to defects and lack of robustness against sharp corners. Thus, it is a challenge to reduce backscattering loss at THz frequencies. In this work, we constructed THz photonic topological insulators and experimentally demonstrated robust, topologically protected valley transport in THz photonic crystals. The THz valley photonic crystal (VPC) was composed of metallic cylinders situated in a triangular lattice. By tuning the relevant location of metallic cylinders in the unit cell, mirror symmetry was broken, and the degenerated states were lifted at the K and K’ valleys in the band structure. Consequently, a bandgap of THz VPC was opened, and a nontrivial band structure was created. Based on the calculated band structure, THz field distributions, and valley Berry curvature, we verified the topological phase transition in such type of THz photonic crystals. Further, we showed the emergence of valley-polarized topological edge states between the topologically distinct VPCs. The angle-resolved transmittance measurements identified the bulk bandgap in the band structure of the VPC. The measured time-domain spectra demonstrated the topological transport of valley edge states between distinct VPCs and their robustness against bending and defects. Furthermore, experiments conducted on a topological multi-channel intersectional device revealed the valley-polarized characteristic of the topological edge states. This work provides a unique approach to reduce backscattering loss at the THz regime. It also demonstrates potential high-efficiency THz functional devices such as topologically protected beam splitters, low-loss waveguides, and robust delay lines.
Intelligent and compact coherent Doppler lidar with fiber-based configuration for robust wind sensing in various atmospheric and environmental conditions
Authors: Kotake Nobuki , Sakamaki Hiroshi , Imaki Masaharu , Miwa Yoshichika , Ando Toshiyuki , Yabugaki Yoshiyuki , Enjo Masayuki , Kameyama Shumpei
Published: April 2022

The intelligent and compact coherent Doppler lidar (CDL) for wind sensing is demonstrated. The configuration is fiber-based. Several functions for the robust wind sensing in various atmospheric and environmental conditions are shown. The main feature of this CDL is the intelligent functions of the beam focusing, spectral accumulation, and window wiping. The supplemental functions of the robust noise floor reduction and motion compensation are also introduced. The effect of the above-mentioned main feature is demonstrated for the improvement of data availability. The evaluation results of the highly accurate wind velocity measurement are additionally shown.
Elasticity measurements of ocular anterior and posterior segments using optical coherence elastography
Authors: Zhang Jisheng , Fan Fan , Zhu Lianqing , Wang Chongyang , Chen Xinyun , Xinxiao Gao , Zhu Jiang
Published: April 2022

The changes of biomechanical properties, especially the elasticity of the ocular tissues, are closely related to some ophthalmic diseases. Currently, the ophthalmic optical coherence elastography (OCE) systems are dedicated either to the anterior segment or to the retina. The elasticity measurements of the whole eye remain challenging. Here we demonstrated an acoustic radiation force optical coherence elastography (ARF-OCE) method to quantify the elasticity of the cornea and the retina. The experiment results show that the Young’s moduli of the cornea and the retina were 16.66 ± 6.51 kPa and 207.96 ± 4.75 kPa, respectively. Our method can measure the elasticity of the anterior segment and the posterior segment, and provides a powerful tool to enhance ophthalmology research.