Electric Power Supply Research Articles

Bacterial cellulose/multi-walled carbon nanotube composite films for moist-electric energy harvesting

Generation of renewable and clean electricity energy from ubiquitous moisture for the power supply of portable electronic devices has become one of the most promising energy collection methods. However, the modest electrical output and transient power supply characteristics of existing moist-electric generator (MEG) severely limit its commercial application, leading to an urgent demand of developing a MEG with high electrical output and continuous power generation capacity. In this work, it is demonstrated that a flexible bacterial cellulose (BC)/Multi-walled carbon nanotube (MWCNT) double-layer (BM-dl) film prepared by vacuum filtration can maintain the moisture concentration difference in the film MEG. Unlike previous studies on cellulose based MEG, BM-dl film has a heterogeneous structure, resulting in a maximum output power density of 0.163 μW/cm2, an extreme voltage of 0.84 V, and current of 2.21 μA at RH = 90 %. BM-dl MEG can generate a voltage of 0.55 V continuously for 45 h in a natural environment (RH = 63–77 %, T = 26–27 °C), which is in a leading level among existing reported cellulose-based MEGs. In summary, this study provides new ideas for innovative design of MEG, which is highly competitive in terms of energy supply for the Internet of Things and wearable devices.

RANCANGAN BANGUN SISTEM OTOMATIS PENGALIH SUMBER DAYA CADANGAN DC BERBASIS BATERAI PACK LITHIUM ION

The development of automatic control system technology, various practical and efficient tools have been created. The purpose of making these various tools is to make it easier to supply electronic electricity in everyday life. Continuous supply of electric power cannot be achieved if only using one power source, without a backup power source. On the other hand, if you use a backup power supply, you need a power supply switching system that works automatically and there is no delay or flashing. This research is related to the Design of Automatic System for Switching Backup Dc Resources Based on Lithium Ion Battery Packs, the purpose of this research is to design an automatic system that works to divert the source of equipment from the main source of PLN to a backup power source of Lithium Ion Battery Pack or vice versa so that the the availability of a power source does not affect the work of the tool. The results show that the designed system can work as expected with the limitation of the Lithium Ion Battery Pack battery with a capacity of 45Ah.

The Bimodal Epithermal Astronuclear Reactor (BEAR): A LONG-LIVED, Universal Space Nuclear Powerplant

A neutronic model of a Nuclear Thermal Propulsion reactor based on the NERVA Peewee design using High Assay Low Enriched Uranium (HALEU) fuel in a Zirconium Carbide matrix has been thoroughly characterised and continuously modified over the last few years at the CSNR. The initial design (Emu, for the flightless bird) created in the summer of 2020 and presented at the NETS 2021 conference, has undergone significant adjustments in this time. Two major investigations have been undertaken and evolved over time; one into the requisites for the provision of electrical power to the propelled spacecraft via the circulation of a noble gas mixture in a closed Brayton cycle, and another into the use of planetary regolith as a reflector, reducing neutron leakage at what would otherwise be the reactor’s end of life in vacuo, rekindling it for an extended period of time as well as providing a very easy ultimate disposal solution, replacing the control drums with rods. It was determined that there are no insurmountable obstacles to performance in either mode.

Revolutionizing mobility: a comprehensive review of electric vehicles charging stations in India

An Electric Vehicle (EV) charger or Electric Vehicle Supply Equipment (EVSE) is a piece of equipment that supplies electrical power for charging plug–in electric vehicles. Although batteries can only be charged with Direct Current (DC) power, most electric vehicles have an onboard Alternative Current AC—to—DC converter and most fully electric cars can accept both AC and DC power. The adoption of EVs can bring about significant relief in noise pollution and also environmental pollution if the required electricity is generated using renewable sources. DC charging stations of various levels are commonly equipped with multiple ports of various levels to be able to charge a wide variety of EVs. EVSEs are found at various facilities such as street–side or retail shopping centers, government facilities, and other parking areas. To ensure a sustainable environment by reducing the carbon emissions from vehicles, the use of EVs needs to be promoted. The need for having Electric Vehicle Charging Stations (EVCS) in any region depends upon the demand and cluster density of EVs in that region and is a major factor in the process of promoting the use of EVs and facilitating sustainable tourism using cleaner fuels. The authors of this study have located the various types and numbers of EVSEs throughout all the states and union territories of India, showing the emerging use of EVs so that EV users can conveniently locate charging stations and plan their routes accordingly. Furthermore, other citizens may be encouraged to own and use EVs for better environmental sustainability.

Comparative Analysis of a Rectifier Performance in Power Generation Applications

Electrical energy's significance is critical to human life, as seen by the rising usage of this resource. Electricity-consuming machinery and technology are developing at an accelerating rate. A substantial electrical power supply is required to achieve these requirements. An effective method to address this issue is to use a generator set powered by an electric motor. This generator necessitates the use of a converter, which serves the purpose of transforming alternating waves (AC) into direct waves (DC), generally referred to as a rectifier. The rectifier's unsatisfactory performance necessitates the need for this research, which seeks to develop and construct a rectifier and subsequently compare its performance utilizing two distinct current sources. Rectifier performance is obtained through the utilization of direct computation and measuring methods. Two sources charge the battery: direct current from the motor and alternating current from the power grid. According to the test results, the converter using an electric power plant source had a higher current value. On the generator, the battery charges up to 13.4 volts in 55 minutes, which is 5 minutes quicker than on the PLN source.

Applications of Electric Heating Technology in Vehicle Exhaust Pollution Control

Motor vehicle exhaust is an important cause of atmospheric pollution. Nowadays, mainstream exhaust emission aftertreatment technologies, such as TWC, DOC, SCR, and DPF, usually require sufficient temperature to perform good purification or maintain normal working conditions. Compared with exhaust gas heating technologies such as engine enrichment and fuel injection, electric heating technology can quickly increase the temperature of exhaust gas aftertreatment devices without adverse effects on engine operating conditions. This article introduces the research and progress of electric heating technology combined with traditional aftertreatment devices on major types of vehicles, such as gasoline vehicles, diesel vehicles, motorcycles, and hybrid vehicles, to improve exhaust purification efficiency and its accompanying fuel consumption impact. In addition, the common structure and characteristics of electric heaters, as well as the current status and development trend of electric heating unit technologies such as electric heating power supply are introduced.

Discussion on Reliability and Power Quality in the Smart Grid: a prosumer approach of a time scalable index

This article presents a discussion related to the measurement techniques of the electric energy quality within the smart grid (SG) context, and considering the producer-consumer (prosumer) approach. It establishes the basis where new power quality (PQ) indexes should be proposed, in order to complement the current recommendations regarding consumer dissatisfaction indexes (CDI) on which the network should be assessed and planned. Indeed, the current indices only consider the number of interruptions and the time during which they occur, and do not take into account neither the type nor the non-linear loads (distributed energy resources, DER) connected to the SG, which are giving rise to new kinds of transients coupled to the electrical power supply signal. In this sense, the paper provides reasons on why temporal evolution of energy and its deviation from the contractual specifications should be monitored and assessed, with the goal of making real-time decisions. Based on advanced statistical signal processing, forecasting methods and artificial intelligence, this focus conveys the conclusive need for a dual measurement index of PQ reliability, on the basis of dynamic temporal scalability, and time-space compressions. A practical example is outlined.

Thermodynamic, Economic and Maturity Analysis of a Carnot Battery with a Two-Zone Water Thermal Energy Storage for Different Working Fluids

The rising share of renewable energies leads to increased fluctuations in electrical power supply. One possibility to shift the surplus energy based on demand is a Carnot battery (CB). A CB uses a heat pump or resistance heater to convert and store thermal energy into electrical energy. Later, the stored thermal energy is converted back into electrical energy using a heat engine. This study investigates a CB with a two-zone tank for thermal energy storage. A transcritical process with CO2 is applied for charging, while discharging employs a transcritical process with CO2 and six refrigerants operating in a subcritical process. The transcritical process with CO2 and the four most promising subcritical processes are compared regarding round trip efficiency and levelized cost of electricity (LCOE) depending on the pinch points 5 K and 1 K in the heat exchangers. Additionally, the technology readiness level (TRL) is determined for these configurations. The results show round-trip efficiencies between 11.3% and 33.5% and LCOEs ranging from EUR 0.95 (kWh)−1 to EUR 2.09 (kWh)−1 for the considered concepts with TRLs of up to six.

Frequency Stability Analysis of a Dynamic Wind Park in an Integrated Power Grid

In spite of rapidly growing wind power capacities, wind power still only accounted for a small fraction of the electric power supply in the last years. Therefore, research in the area of wind power was mostly focused on the wind generators and wind parks themselves, aiming to maximize their efficiency and stability. But as the weight of wind power grows, their influence on power systems cannot be neglected anymore. That is why recent research like [1], [2] or [3] studies the effects that wind parks have on the dynamic power grids they are connected to. Continuing in this direction, we implement a simulation model of a power grid including a wind park and study its dynamic behavior with varying wind speed. The influence of certain parameters like transmission line length, rated power of the wind park or control depth on the frequency stability in the power system are studied and analyzed. Furthermore, a control scheme to integrate the wind park into the grid frequency control is implemented.

Analysis the islanding mode of combined operation of DG and UPQC in unbalanced distribution system

The proposed system consists of a series inverter, a shunt inverter, and a Distributed Generation (DG) connected in the dc link. It focuses on improving the power quality and ensuring the continuity of the electric power supply. The function of the scheme has been investigated in islanding mode which is a challenging mode of UPQC. The formulation of the proposed control scheme which is based on the instantaneous power theory is described. The proposed system can improve the power quality at the point of installation on power distribution systems or industrial power systems. Compensation of reactive power at the Point of Common Coupling (PCC) is examined. The effectiveness of the proposed scheme has been verified by simulation.

Carbon emission reduction capability assessment based on synergistic optimization control of electric vehicle V2G and multiple types power supply

With the increasing proliferation of electric vehicles (EVs) and the integration of renewable energy sources into the power system, significant challenges have arisen for power system load balancing and stability control. The carbon emission reduction capability of power systems through coordinated optimization control of electric vehicles and power sources has garnered considerable attention. This paper evaluates the impact of Vehicle-to-Grid (V2G) and power source coordinated optimization control on the carbon emission reduction capability of power systems, proposing a technique that takes into account the dynamic characteristics of electric vehicles, power sources, and carbon emissions. This approach integrates V2G technology, renewable energy generation, and load demand into a framework aimed at optimizing power system operations and minimizing carbon emissions. A case study using real load data from a city assesses the impact of EV V2G and power source coordinated optimization control on carbon reduction. The results indicate that by 2025, peak-valley regulation will reach 1211,000 MW, with a carbon reduction of 138,783.799 tons, corresponding to a total reduction ratio of 1.101%. This research can provide valuable insights for policymakers, power system operators, and researchers.

Titanium foil-sealed thermoelectric generator for seafloor hydrothermal vent

The seafloor hydrothermal activity observation equipment needs a stable electric power supply; this study explored the thermoelectric generator (TEG) as the in-situ power supply method. The TEG can utilize the considerable temperature difference of the hydrothermal vent to supply electricity for the observation system. We use the titanium foil combined with the O-ring as the sealing component, thus can decrease the cold side thermal resistance and obtain a compact structure. The pressure test result shows the TEG can withstand pressure up to 20 MPa without leakage. Furthermore, a simulation is conducted to evaluate the temperature distribution of the TEG. To reduce heat loss, Polyetheretherketone (PEEK) material is used as the heat insulation layer at the surface of TEG. The simulation shows that adding the heat insulation layer can increase the hot side temperature by 4.9–7 K. The pool power generation results show that the novel structure TEG can realize 22 W output at the hot fluid temperature of 467 K. This study provides a novel sealing method for seafloor equipment with corrosion-resisting and low thermal resistance features.

Power factor correction of three-phase electrical power supply by using of thyristor controlled reactor VAR compensator

Low power factor (abbreviated as pf), particularly lagging pf, brings a lot of negative effects to electrical power supply system. Lagging pf is caused by inductive load. Inductive load with low pf draws higher current for the same active power demand. Higher current results in larger kVA rating and size of all electrical equipment connected to the electrical power system, larger conductor size used to deliver electrical power to the load, higher loss hence poorer power distribution efficiency and higher voltage drop hence poorer electrical power system voltage regulation. Considering all these negative effects, reactive power (VAR) compensation is needed. This paper analyses characteristics of a VAR compensation method called Thyristor Controlled Reactor (TCR) applied in three-phase electrical power system supplying an inductive load. A TCR consists of three sets of a capacitor connected in parallel with an inductor. The capacitor will supply a certain amount of reactive power needed by the load. The inductor is connected in series with an electronic static switch named as TRIAC to control the amount of reactive power absorbed by it. When reactive power supplied by the capacitor is higher than reactive power demanded by the load, the switching angle of TRIAC is controlled in such a way that excess of reactive power supply is absorbed by the inductor. In this work, three capacitors in which capacitance of each of it is equal to 50 µF as well as three inductors in which inductance of each of it is equal to 200 mH are used to compensate an inductive load which has power and pf vary from 1.5 kW to 4.6 kW and 0.46 to 0.84 respectively. By controlling the switching angle of TRIAC, pf of the three-phase electrical power system is successfully maintained close to unity at 0.95 following changes of the load. However, further analysis shows that operation of the TRIAC results in increase of current harmonics. Average of total current harmonic distortion (THD) increases from 15.13% to 18.45% due to use of TCR. On the contrary, voltage total harmonic distortion (THDV) after TCR installation is slightly lower than before TCR installation.

Managing electric motive power modes with regard to traction energy operation conditions

Improving the energy efficiency of electrified railways is an urgent goal, one of the possible solutions to which is the situational control of electric traction loads depending on their priority, taking into account the instantaneous load of the traction power supply system. The aim of this research is to develop a mathematical model and principles of control of electric traction trains on the basis of instantaneous traction calculations, taking into account the modes of operation of the traction power supply system of railways in conditions of energy infrastructure limitations. The paper presents the results of mathematical modeling of mutual influence of electric traction and traction power supply system on the parameters of operation, as well as the mathematical formulation of realization of operation modes of electric traction at demand management by electric traction loads applied to the considered electrified section. As a result of the calculations for one moment of time the values of adjustment of active power of electric traction trains for fulfillment of restrictions of instantaneous load of power lines of traction equipment (15.9 MW) and provision of voltages in the traction network within permissible limits in the given train situation are obtained. The presented approach will allow to obtain restrictions of train movement in the zone between substations, to determine the maximum speed of train movement on the basis of energy conditions in the real situation, to coordinate control actions between trains on the basis of their priority (schedule adjustment) depending on the load of traction substations.

Students’ use and assessment of Plateau State University Library, Bokkos

This paper focuses on use and assessment of various resources and facilities of the Plateau State University Library, Bokkos. The research was guided by seventeen objectives. A survey research design was the research method adopted in the investigation. The target population for the research was all the 499 students in the Faculty of Natural and Applied Sciences that were on ground in 2022/2023 academic session. Since the population was manageable, there was no sampling. Hence, all the subjects were adopted in the research. The instrument used in the data collection was questionnaire. Data collected were analyzed using simple statistics such as frequency counts and percentages, and tables were presented were necessary. The findings of the research revealed among others that the major issues associated with the poor patronage of the Plateau State University Library, Bokkos by the students of the institution were as follows: lack of enough textbooks and journals; collection contain so many outdated textbooks that were irrelevant to the student‟s needs; library‟s catalogue was in disarray; lack of stable source of electric power supply; and inconsistent internet connections with very low internet bandwidth. It was therefore, recommended among others that the library management should acquire more current text books and journals in both hard and soft copies and the university‟s lecturers (users) should be involved in the selection of the library‟s resources for acquisition in order to improve the quality / relevancy of the library‟s collection; there is an urgent need to reorganize the library‟s catalogue to reflect the library‟s collection; the university management should provide a constant source of electric power supply to the library; Internet connectivity should be made available all the time and internet bandwidth should be 4increased to reduce the time it takes to gain access into the internet databases in the library. The research then concluded that the Plateau State University library was bedeviled with so many factors that had inhibited the effective utilization of its resources and facilities by students. Hence, students avoided the patronage of the library‟s resources and facilities. However, it was believed that with proper funding, commitment of university and library managements and careful implementation of the recommendations noted in this research, the resources and facilities of the library will be greatly improved and the patronage of the library by students will subsequently improve.

Optimal Switch Insertion for Power Loss Reduction and Reliability Enhancement in the Nigeria Conventional Distribution Networks: A Case Study

This paper seeks to analyze the potentials of optimal switch insertion and relocation of the existing ones in the Nigeria conventional distribution network for reliability enhancement and power loss minimization. Maximizing customers’ satisfaction and enhancement of service reliability of the distribution network isa critical thing to utility and how to achieve it is also a major concern? Optimal switch insertion can enhance the network operation, minimize power losses in the lines, increase service restoration to blackout areas and improve the electric power supply to customers in the distribution network and increase the system reliability. The impact of optimal insertion of sectionalizing switches and optimal relocation of the existing ones for reliability enhancement and power loss reduction in real-time distribution network has been investigated. Additionally, the research examined the history of frequent power interruptions in the network and their cost implication on the system and customers alike, and as well as the benefits of eliminating frequent outages in the Nigeria distribution networks as a case study. Also, feeder ranking based on reliability indices, customer damage function (CDF), capital investment and their correlations were analyzed and established. Conclusively, the results depicted that the reliability of the network can be affected by the number of sectionalizing switches introduced by an optimal relocation of the existing ones and their locations as well as its capacity of power loss reduction in the network.

Optimal Resiliency‐Oriented Scheduling Framework for Integrated Power‐Gas‐Transportation Networks Based on Model Predictive Control Approach to Increase Electric Load Supply

Today’s societies need a sustainable supply of energy more than ever, whereas unseen events challenge the electric power supply. The coordinated operation of a power‐gas‐transportation system can decrease the effects of such faults in the distribution level. This paper proposes a model predictive control approach for dynamic load restoration in an integrated energy system. The coordination of electric and gas networks besides the mobile energy storage (MES) units provides a novel resilient alternative to serve active and reactive loads. First, the location and time of drastic events are identified as the initialization phase in this paper using a vulnerability analysis by a master–slave problem to find the weak points of the electric grid. Then, a rolling horizon model predictive control‐based approach is proposed to make corrective decisions to serve loads. Meanwhile, a new linearization approach for the Weymouth equation has been proposed based on the binary expansion method. The proposed linear resiliency‐oriented scheduling problem is tested on IEEE 33‐bus and IEEE 69‐bus integrated with a seven‐node gas distribution grid and a six‐station transportation railway. The analysis revealed that the coordination between electric and gas resources minimizes the not‐supplied load; MES units act as certain emergency tools to serve the critical loads.

Анализ особенностей конструктивного исполнения и направления совершенствования многопульсовых выпрямительно-инверторных преобразователей для тяговых подстанций железных дорог

The article considers the parameters, characteristics, energy indicators, peculiarities of the structural embodiment and the regimes of work of multi-pulse inverting and rectifying-inverting converters for traction substations. These converters are intended to increase the energy efficiency and the safety of the work of the system of the traction DC electric power supply including the areas of the electric railways with heavy and high-speed railway traffic. The main advantages of the use of 12-pulse circuits of inverts in comparison to 6-pulse ones have been presented. The directions for further improvement of the multi-pulse inverting and rectifying-inverting converters for traction substations have been suggested.

Optimizing renewable polygeneration: A synergetic approach harnessing solar and wind energy systems

Transitioning from fossil fuels to renewable energy ensures a sustainable and green future by limiting greenhouse gas emissions and their nuisance effects. This study proposes a polygeneration system that harnesses renewable energy to produce multiple energy vectors simultaneously and equipped with storage to mitigate the impact of intermittent weather. To perform dynamic analysis, proposed system has been modeled, optimized, and simulated using the transient simulation software TRNSYS®. The designed model has been optimized in GenOpt, linked with TrnOpt, under the weather conditions of Gujrat, Pakistan. The power system is energized by solar photovoltaic, thermal and wind power to produce cooling, heating, electricity, hydrogen, and oxygen as energy vectors, and also provides electric, hydrogen, and thermal storage. Prime movers utilized for energy conversion consists of evacuated glass tube collector, photovoltaic panels, wind energy conversion system, fuel cell, electrolyzer, and absorption chiller, which facilitate air-conditioning, space and water heating, electric power supply for electric vehicle, building load & national grid, hydrogen for internal combustion engines, fuel cell electric vehicle and industrial applications, as well as oxygen for hospitals. The study has shown that thermal collector has 68% efficiency, a solar fraction 0.78, peak outlet temperature 143.77 °C, and generates a total 1399656.25 kJ thermal energy. The wind and photovoltaic systems have maximum efficiencies values 52.24 % and 10.90 % respectively, resulting in the production of 44.8 MWh electric energy. Embracing the synergy of solar and wind power in a polygeneration system holds the key to a sustainable and eco-friendly future.

Development of an industrial solid waste ecological analysis model in Shanghai, China.

Amid China's rapid economic expansion, the country's industrial solid waste (ISW) problem is escalating. As each sector generates distinct types of ISW, a multi-indicator assessment of each sector is essential to address China's New Solid Waste Policy. To investigate the ISW situation of each sector and perform a comprehensive assessment, we formulate an industrial solid waste ecological analysis framework based on ISW generation and ISW flow in the sector. Various indicators (i.e., solid waste utilization coefficient, solid waste threat coefficient, and solid waste threat intensity) are employed to assess the utilization of solid waste generated for each sector, as well as the threat of solid waste originating in each sector to society. Ecological network analysis probes the interrelationships between diverse sectors. Taking Shanghai in 2017 as an example, the study indicates that some sectors (e.g., production and supply of electric power and heat power (EH) and metal smelting and rolling processing sector (MS)) exhibit higher direct ISW generation and the direct industrial solid waste value-added coefficient (SVAC) for common industrial solid waste (CISW). Specifically, the direct CISW generation of EH and MS is 539.21Mt and 277.00Mt respectively. The direct SVAC of EH and MS is 157.06kg/103RMB and 126.27kg/103RMB respectively. These sectors should prioritize reducing emissions at the source. Additionally, the threats to society from various sectors are relatively insignificant for the CISW, while for the hazardous waste (HW), all sectors pose a considerable threat to Shanghai's society. Moreover, some sectors (e.g., mining industry) exhibit the highest mutualism relationships in the CISW and the HW. Enhancing mining sector technologies is a vital strategy for mitigating ISW sources. Specifically, MI has 9 pairs of mutualism relationships in the CISW and 8 pairs in the HW. These insights will provide empirical evidence for tackling the ISW problem in Shanghai.