Electrical Energy Research Articles

A light-temperature neuron and its adaptive regulation

Abstract The appropriate firing modes for a neuron can be excited under the external stimulus. From the viewpoint of physical, the intrinsic biophysical effects, functional encoding, and the mechanism for the transcription of external signals play an extremely important role in building reliable neuron models. In this paper, a light-temperature neuron model is proposed by connecting a phototube and a thermistor into a nonlinear circuit for investigating the information encoding and responses of neurons under the external optical signals and temperature signals. In this neuron model, a phototube is used to encode external light signals, similar to artificial eyes, and a thermistor can encode temperature intensity. Furthermore, the Hamilton energy (HE) function of neurons is calculated based on the Helmholtz’s theorem, and a self-regulation method is designed by applying the ratio of electric field energy to magnetic field energy to estimate the self-regulation of neurons. The results show that the proposed neuron can reproduce the main characteristics of biological neurons by adjusting the external stimulus. The double coherence resonance is induced under noise temperature. These results could be helpful for researching the collective behaviors in functional neural networks.

An Analysis of Potential for Reducing Operational Costs Through The Use of LED Lighting in Indonesian Hotel

Indonesia has significant tourism potential, which drives the growth of the hospitality industry and increasing energy needs. Large energy consumption in hotels, especially in lighting systems, leads to high operational costs and carbon emissions. This study aims to analyze the potential for reducing operational costs through the use of LED lighting at the Bumi Sawunggaling Hotel, Bandung. The methods used include field observation and energy consumption measurement using a Power Quality Analyzer (PQA) for one week, with data taken every 30 minutes. The results of the study show that the hotel's electrical energy consumption reaches 923.45 kWh per week at a cost of IDR 1,334,166. By replacing conventional lighting with LED, hotels can reduce energy consumption by up to 80%, which translates to operational cost savings of 30% or more. The conclusion of this study emphasizes that the application of LED technology not only provides financial benefits but also supports environmental sustainability. The implication of this study is the importance of adopting energy-saving technologies such as LEDs in the hospitality sector as a strategic step to reduce costs and carbon emissions and improve the hotel's reputation as an eco-friendly business, besides that it is very important for Hotel Bumi Sawunggaling to replace its conventional lighting with LED lights to achieve higher energy efficiency. LED lights are known for their superior energy efficiency compared to traditional incandescent lamps or CFL (Compact Fluorescent Lamp) lamps.

Stochastic economic sizing and placement of renewable integrated energy system with combined hydrogen and power technology in the active distribution network.

The current study concentrates on the planning (sitting and sizing) of a renewable integrated energy system that incorporates power-to-hydrogen (P2H) and hydrogen-to-power (H2P) technologies within an active distribution network. This is expressed in the form of an optimization model, in which the objective function is to reduce the annual costs of construction and maintenance of integrated energy systems. The model takes into account the planning and operation model of wind, solar, and bio-waste resources, as well as hydrogen storage (a combination of P2H, H2P, and hydrogen tank), and the optimal power flow constraints of the distribution network. Electrical and hydrogen energy are administered in an integrated energy system. The modeling of the uncertainties regarding the quantity of load and renewable resources is achieved through stochastic optimization using the Unscented Transformation method. The novelties of the scheme include the sizing and placement of a combined hydrogen and power-based renewable integrated energy system, the consideration of the impacts of bio-waste units, P2H, and H2P systems on the planning of the integrated energy system and the operation of the active distribution network, and the modeling of uncertainties using the Unscented Transformation method to reduce the calculation time. The study's results demonstrate the scheme's ability to improve the technical conditions of the distribution network by considering the optimal planning of integrated energy systems. In comparison to the network power flow, the operation status of the network has been improved by approximately 23-45% through the optimal siting, sizing, and energy management of hydrogen storage equipment, as well as renewable resources in the form of integrated energy systems. In other words, optimal energy management and planning of the integrated energy systems in the distribution network has been able to reduce energy losses and voltage drop by 44.5% and 42.4% compared to the load flow studies. In this situation, peak load carrying capability has increased by about 23.7%. In addition, compared to the case of the network with renewable resources, the overvoltage has decreased by about 43.5%. Also, Unscented Transformation method has a lower calculation time than scenario-based stochastic optimization.

Electro-hyperelasticity with phase field for electric breakdown modeling

In this paper, we systematically derive the phase field model for electric breakdown channel propagation. The model includes electric charge, mass, momentum and energy conservation equations as well as Allen–Cahn type equation which governs the phase field evolution. The medium motion is described by the Godunov–Romenski type hyperelastic model. Electromagnetic part of the model consists of Maxwell’s equations in quasi(electro)stationary approximation including electric charge conservation law. Derivation of the model is based on the Coleman–Noll procedure and Gurtin’s microforces and microstress framework.

Advanced Electrode Materials for Low‐Temperature Na Storage

AbstractSodium‐ion batteries have drawn worldwide attention as ideal candidates for the upcoming generation of large‐scale electrical energy storage devices due to the low cost and abundance of sodium. Due to its unique electrochemical and chemical properties, sodium‐ion batteries hold the promise of breaking geographical and environmental constraints, achieving efficient sodium storage under low‐temperature conditions. However, low‐temperature sodium‐ion batteries, especially for their electrode materials, still face numerous challenges, such as the sluggish electrochemical reaction kinetics, poor material stability, significant volume changes leading to the pulverization of materials and the rapid degradation of battery performance. Here, it is focused on the modification methods for electrode materials, the research progress on cathode and anode materials of low‐temperature sodium‐ion batteries is summarized systematically and the other components of the electrodes are discussed briefly, and the shortcomings of the current research and possible future research directions are discussed thoroughly.

Electrical characteristics of photovoltaic (PV) solar panel and hybrid PV/thermal (PV/T) solar panel

Solar collectors and photovoltaic (PV) solar panels can convert solar radiation into heat and electrical energy. A hybrid PV/thermal (PV/T) solar panel was tested in this study. The hybrid PV/T solar panel was tested using a spiral absorber and water flow levels range from 0.01 kg/s to 0.03 kg/s. As a result, with variable water flow rates and irradiation intensity of 700 and 900 W/m2, the efficiency of hybrid PV/T solar panels varied. The highest electrical efficiency attained was 4.06% in hybrid PV/T solar panels at 900 W/m2 with 0.025 kg/s of mass flow while 3.65% by PV solar panels. In addition, plotted current-voltage and power-voltage curves were used to show the electrical properties of the solar PV panels and hybrid PV/T solar panels.

On the issue of reliability of power transmission (on the example of the branch of PJSC Rosseti Volga – Penzaenergo)

The article is a continuation of a series of publications focusing on the analytical assessment of specifics of power transmission in various structural divisions of PJSC Rosseti and is dedicated to the consideration of specific features of electric energy transport in the PJSC Rosseti Volga – Penzaenergo branch electric networks over the period of 2018 – 2023. The characteristic of the structural and balance state of the company's electrical networks for the period under study is presented. Based on the data published in the open press, the analysis of the number of emergency shutdowns and their consequences in electric networks of all levels of rated voltage was carried out. In accordance with the accepted classification, the intensity of these outages was analyzed depending on the amount of electrical energy undersupplied to consumers. The percentage ratio of the value of electrical energy not delivered as a result of emergency shutdowns is analyzed according to the accepted criteria of the intensity level of these failures. It was found that the smallest number of failures of extreme intensity accounts for more than 25% of undelivered electrical energy. The percentage ratio of the amount of electricity not delivered as a result of emergency outages is compared with losses of electricity as a result of unauthorized connections. Specific groups of causes of emergency shutdowns have been identified and the percentage ratio of the number of failures due to these causes to the total number of failures during the period under study has been determined. General scientific methods and methods of numerical analysis were used in the study. The technologies of Excel, Paint 3D software shells, MATLAB graphics editor, as well as author's software solutions were used as a tool base. The results obtained may be of interest to the management of the power grid structures of the Russian Federation, as well as to engineers and researchers engaged in research in the field of improving the reliability of power supply to consumers.

Study of Ionanofluids Behavior in PVT Solar Collectors: Determination of Thermal Fields and Characteristic Length by Means of HEATT® Platform

Solar electric and solar thermal energies are often considered as part of the solution to the current energy emergency. The pipes of flat plate solar devices are normally heated by their upper surfaces giving rise to an asymmetric temperature field in the bulk of the fluid, which influences the heat transfer process. In the present work, a study of the characteristic length of tubes, or most efficient distance at which heat transfer occurs, in flat photovoltaic-thermal (PVT) hybrid solar devices has been carried out using three heat transfer fluids: water, [Emim]Ac ionic liquid and ionanofluid of graphene nanoparticles suspended in the former ionic liquid. The mean objective of the study was to know whether the heat transfer occurs in optimal conditions. Experimental measurements have been made on a commercial PVT device, and numerical simulations have been performed using the HEATT® platform to determine the characteristic length of the process. The tests conducted showed a clear improvement in the temperature jump of the fluid inside the collector when INF is used compared to water and ionic liquid and even a higher overall energy efficiency. Electricity generation is not greatly affected by the fluid used, although it is slightly higher when water is used. Slower fluid velocities are recommended if high fluid outlet temperatures are the goal of the application, but this penalizes the overall thermal energy production. The characteristic process length is not typically achieved in parallel tube PVT collectors with ordinary flow rates, which would require a speed, and consequently, a flow rate, about 10 times lower, which penalizes the performance (up to four times), although it increases the fluid outlet temperature by 234%, which can be very interesting in certain applications. Ionanofluids may in the medium term become an alternative to water in flat plates or vacuum solar collectors for applications with temperatures close to or above 100 °C, when their costs will hopefully fall. The results and methodology developed in this work are applicable to solar thermal collectors other than PVT collectors.

Statistical Analysis of Levelized Round Trip Cost of Grid Scale Electrical Energy Storage in Batteries with Different Chemistries

Electrical energy storage is a crucial component of the clean energy transition for integrating high share of renewable electricity generators into the supply mix. In this study, the round-trip costs of grid scale electrochemical energy storage from 2 up to 24 hours for peak power ratings of 1 MW and 10 MW in lithium-ion LFP, lithium-ion NMC, Pb-acid and vanadium redox flow batteries are compared using their currently projected techno-economic characteristics for year 2030. A statistical approach is used for estimating mean costs and quantifying the uncertainties in these estimates, since many of the techno-commercial features are still evolving and are uncertain. Using Monte Carlo simulations to derive the input parameters, the levelized round trip cost of energy storage is found to vary from Rs 10.73±0.77/kWh(e) to Rs 15.96±1.12/kWh(e) for Li-LFP batteries, Rs 14±1/kWh(e) to Rs 20.3±1.46/kWh(e) for Li-NMC batteries, Rs 19.1±1.39/kWh(e) to Rs 58.3±4.28/kWh(e) for Pb-acid batteries and Rs 18.7±1.37/kWh(e) to Rs 44.2±3.19/kWh(e) for Vanadium redox flow batteries, for the range of input values considered in this study. Through sensitivity analysis and calculation of correlation coefficients, the battery installed capital cost and useful lifetime are found to be the two most influential parameters affecting life cycle electrical energy storage cost.

High Gradient Magnetic Fields Generated in Events on the 230 kV Electric Power Transmission Infrastructure: Human Exposure Analysis and Risk

This work presents a process for analyzing human exposure to high-gradient magnetic fields based on protection models for patients undergoing magnetic resonance examinations developed by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). A series of events presented in the electrical energy transmission infrastructure is taken, with typical currents and front times, a case of extreme failure is added, and results are presented. Subsequently, with a classic lightning signal, compliance with the exposure to this type of field in the right-of-way strip of a transmission line is verified and validated in the event of a hypothetical atmospheric discharge impact event. Finally, a simulation is implemented with space discretization techniques, establishing the signal resulting from the magnetic field generated as a function of time. The exposure is evaluated using the presented model. Only in one of the analysis cases was it found that the perception threshold is exceeded at distances less than 0.6 cm, virtually a situation in which the worker has contact with the down conductor. With the results obtained and the cases analyzed, it is concluded that failures of this type do not generate significant exposure to high-gradient magnetic fields and do not exceed the determined perception thresholds.

UJI EKSPERIMEN PENGARUH JUMLAH SUDU DAN DEBIT TERHADAP DAYA DAN EFISIENSI TURBIN AIR TIPE VORTEX

<p class="StyleAuthorBold"><em>The electrification ratio in Indonesia is currently still 87%. This means that there are still 8.5 million residents or the equivalent of 2500 villages that have not received electricity. Indonesia has a lot of potential for renewable energy such as water energy. 7 GW capacity from renewable energy, 66% of which comes from hydropower. The manufacture of pico-hydro scale power plants can be a cheap alternative. Pico-hydro can be applied to irrigation canals so that it can produce small-scale electrical energy. One type of water turbine that can be utilized is a vortex type water turbine. The study used experimental methods. The independent variables are variations in the number of blades 2, 4, and 6 and the distance between the blades and the outlet is 1 cm. The dependent variable of the research is the power and efficiency produced by the vortex water turbine. The data analysis technique in this study used quantitative descriptive analysis techniques. The basin used is a conical basin type with the upper diameter is 40 cm, the lower/oulet diameter is 6.5 cm, and the height is 32 cm. The water discharge in this test has 7 variations, that is 1,12 l/s, 1,26 l/s, 1,54 l/s, 1,68 l/s, 1,82 l/s, 1,96 l/s, and 2,11 l/s. This test produced the highest electrical output power of 9.66 Watts, at a total of 2 blades, the discharge is 1,86 l/s. At the number of blades 6 at a discharge of 1.96 l / d is the highest efficiency value of 6.3%.</em></p>

Intelligent Control of an Experimental Small-Scale Wind Turbine

Nowadays, wind turbines are one of the most popular devices for producing clean and renewable electric energy. The rotor blades catch the wind’s kinetic energy to produce rotational energy from the turbine and electric energy from the generator. In small-scale wind turbines, there are several methods to operate the blades to obtain the desired speed of rotation and power outputs. These methods include passive stall, active stall, and pitch control. Pitch control sets the angular position of the blades to face the wind to achieve a predefined relationship between turbine speed or power and wind velocity. Typically, conventional Proportional Integral (PI) controllers are used to set the angular position of the rotor blades or pitch angle. Nevertheless, the quality of speed or power regulation may vary substantially. This study introduces a rotor speed controller for a pitch-controlled small-scale wind turbine prototype based on fuzzy logic concepts. The basics of fuzzy systems required to implement this kind of controller are presented in detail to counteract the lack of such material in the technical literature. The knowledge base of the fuzzy speed controller is composed of Takagi–Sugeno–Kang (TSK) fuzzy inference rules that implement a dedicated PI controller for any desired interval of wind velocities. Each wind velocity interval is defined with a fuzzy set. Simulation experiments show that the TSK fuzzy PI speed controller can outperform the conventional PI controller in the speed and accuracy of response, stability, and robustness over the whole range of operation of the wind turbine prototype.

Unit commitment in solar‐based integrated energy distribution systems with electrical, thermal and natural gas flexibilities: Application of information gap decision theory

AbstractThe depleting oil reserves, air pollution and increasing energy demand, have overturned the focus of the scientific community to renewable energy sources. Among which the photovoltaic (PV) systems occupy more than half of the market share and are generally installed at the distribution level. The volatile and uncertain nature of these PV productions necessitates flexible resources in energy systems. To this end, the district heating systems have an outstanding flexibility on account of their high thermal inertia. This study investigates the optimal unit commitment scheduling for gas‐fired and non‐gas‐fired distributed generation units (NGU) in an integrated energy distribution system (IEDS) within the physical constraints of the electrical, natural gas and thermal energy distribution networks. Moreover, a planning‐based optimization framework is proposed to investigate the investment of battery storage systems in the electric distribution network under the high penetration of PV systems with the aim of enhancing flexibility and reducing the operating costs of the IEDS. In this framework, the information gap decision theory is deployed under risk‐averse and risk‐seeker strategies to deal with uncertain PV energy production. Additionally, the environmental emissions are considered in a multi‐objective approach. The IEDS is embodied through IEEE 33‐bus EDS, 20‐node natural gas network and an 8‐node district heating systems. Eventually, The proposed approach makes a noteworthy contribution to the advancement of solar energy systems in IEDS.

Minimum energy principles in electrostatics

Abstract We employ the principle of minimum energy of the electrostatic field to derive Laplace's equation for electric potential in charge-free space. We also apply the principle of minimum electrical potential energy of a system of discrete charges to explain the possibility of the existence of their stable equilibrium configuration on the surface of a conductor.

A frequency reconfigurable antireflection metasurface for GPR

Abstract The antireflection metasurface (AM) is employed in ground penetrating radar (GPR) to mitigate the strong reflection of electromagnetic waves at the air-ground interface due to impedance mismatch. However, due to constraints imposed by the relative bandwidth (RBW) and manufacturing processes, these layers tend to exhibit excessive thickness and bulky shape, narrow RBW, and fixed functionality in a passive configuration. This paper presents a novel, dual-band, independent wideband tuning, frequency reconfigurable AM based on varactor diodes with center frequencies of 1.35 GHz and 2.60 GHz. This metasurface possesses positive properties such as a single layer, the ultrathin thickness (0.03 & 0.06λ), the wide RBW (43.3% & 27.4%) and remarkable antireflection. The aforementioned metasurface achieves the described mechanisms and features through the destructive interference theory and the combine element technique. Numerical simulation results of surface currents and electric field energy power demonstrate the antireflection property. The equivalent electromagnetic parameter retrieval results also provide equivalent impedance conditions for non-perfect antireflection. The proposed AM samples demonstrate notable stepwise frequency reconfigurable properties in free-space experiments. The imaging effect after loading this AM is significantly improved in real-world GPR ballast roadbed anomaly detection experiments. This approach provides significant research value and promising prospects across various disciplines, including the stepped-frequency GPR, microwave imaging, and interdisciplinary fields.

Design Study for a Superconducting High-Power Fan Drive for a Long-Range Aircraft

New aerodynamic aircraft concepts enable the storage of volumetric liquid hydrogen (LH2). Additionally, the low temperatures of LH2 enable technologies such as the superconductivity of electrical fan drives and power distribution components. An increased power density of the onboard wiring harness and the electrical machine can be expected. The highest system efficiency and the smallest fuel and tank weight will be achieved with a highly efficient energy conversion by the fuel cell from LH2 to electrical energy. This publication shows a comprehensive study for cryogenic fan drives based on experimental-driven tape superconductor investigations, mission profile-based considerations, design analyses of superconducting electrical machines, and studies of the cooling concepts. A cryogenic system cannot be considered without a feasible cooling concept. Here, an approach with a safe He-based cooling system is proposed, using the LH2 flow to the fuel cell as a heat sink for the losses in the electrical system.

Design and simulation of a smart master switch system based on multi-input XOR logic gate

AbstractMechanical switches have been the conventional way of controlling electrical energy in different electrical systems such as: lighting systems, socket systems, and circuit breakers, especially in domestic, hospital, and industrial applications. Mechanical switches often require physical access to control different electrical devices that are connected to the power sources. The work presented in this paper aimed at designing and simulating a multi-input based Exclusive-Or master switch system that remotely controls the lighting and socket systems using the wireless switching mechanisms of Global System for Mobile communication and Bluetooth. The system therefore limits physical interaction that require use of the single pole double throw and keypad mechanical switches that are however included to act as fall-back mechanism in control of electrical devices. Within the recommended electrical safety measures, the design can be streamlined and integrated to remotely control lighting systems and sockets alongside the conventional mechanical switches in the consumer control unit.

Integration of a solid oxide electrolysis system with solar thermal and electrical energy: A testing campaign for operation and control strategy definition

AbstractThe EU project PROMETEO has the scope of testing a 25 kW solid oxide electrolysis system integrated with a concentrated solar power plant via thermal energy storage in a relevant environment. Given the plant layout and the hydrogen demand characteristics, this work aims to identify how to operate the system effectively when renewable electricity is unavailable and how to modulate the load during hydrogen generation, thus defining the system's operation modes and control strategy. A 5 kWe stack has been tested at the FBK facility. The hot standby tests show that feeding a reducing gas at the negative electrode and air at the positive electrode, without polarizing the stack, effectively keeps the stack hot at 750°C and prevents degradation. Conversely, the electric protection approach leads to significant stack degradation (15% voltage drop in 200 h for one cluster). Regarding modulation of hydrogen generation, with low steam flowrates, the stack current and the flow rate of produced hydrogen mainly depend on the steam flow rate, while it is not affected by the stack temperature; conversely, with high steam flowrates, the current depends only on the stack temperature (from 25 A at 670°C to 65 A at 760°C). Based on the results, two hot standby modes and two load control strategies to be implemented and tested in the PROMETEO prototype are proposed.

Design of high-performance binary carbonate/hydroxide Ni-based supercapacitors for photo-storage systems

Silicon solar cells were used to convert solar energy into electrical energy, and a supercapacitor was designed to store this energy. To maximize the surface area of the electrodes, a three-dimensional Ni foam substrate was employed, onto which Ni-based compounds were deposited to enhance the electrochemical performance of the electrodes. Specifically, to address the conductivity reduction problem that arises when using only Ni ions, we introduced transition metal ions such as Mn, Co, Cu, Fe, and Zn to create binary compounds as electrode material. These binary metal compounds provided high electronic conductivity, structural stability, and reversible capacity, thereby optimizing the performance of the supercapacitor. As a result, the optimized NiCo(CO3)(OH)2 electrode demonstrated high capacity and excellent cycle stability, exhibiting an energy density of 35.5 Wh kg−1 and a power density of 2555.6 W kg−1 as an asymmetric supercapacitor device. Furthermore, when this device was combined directly with silicon solar cells, it achieved a storage efficiency of 63 % and an overall efficiency of 5.17 % under an illumination intensity of 10 mW cm−2. These findings suggest the potential for commercializing high-performance self-charging energy storage devices and contribute significantly to the advancement of energy storage technology.

The Eectricity Crisis and the Feasibility of Nuclear Energy in Egypt

The power outage crisis is increasing in Egypt, negatively affecting many other sectors such as industry, agriculture, and trade. In light of the lack of sufficient capacity to meet the growing needs of consumers, which has led to regular power shortages and power outages. While Egypt needs additional energy, the production of gas and oil needed to generate thermal energy decreased in 2014, and Egypt moved from an exporter of natural gas to a net importer. In addition to this, the volume of subsidies allocated to energy increased, the rise in global prices for oil and natural gas, and the need for huge investments to create Power generation plants, development of transportation networks, and distribution of electrical energy, which led to pressure on the general budget. A continuous and reliable supply of electricity is needed for Egypt's social and economic development. Accordingly, the government encouraged the development of new energy, invited the private sector to participate in energy generation, and a number of government reforms were made in order to enhance competition in the energy market, which required the need to study the possibility of providing it using nuclear energy. Its stations have a high load capacity, operate almost at full capacity all the time, are characterized by the stability of the electrical network and energy independence, and avoid the risks of fuel price shocks, and the costs of generating electricity from them decrease with increasing production. The importance of this research lies in highlighting the challenges facing the structure of the electricity sector in Egypt, and studying the advantages enjoyed by nuclear energy as the most important renewable energy sources in the world. Its importance also lies in comparing nuclear energy with other energy sources, and trying to benefit Egypt from obtaining this energy for use. In economic development projects, rationalizing tariffs and supporting their access to the poor. <i>This research is divided into</i>:<i>The first topic</i>: The electricity generation crisis in Egypt and a development vision for the contribution of nuclear energy to its solution, <i>The second topic</i>: trends in development planning for establishing nuclear plants in Egypt. The electricity generation crisis in Egypt and a development vision for the contribution of nuclear energy to its solution.