Problem Of Power Supply Research Articles

Ionic Gelatin-Based Flexible Thermoelectric Generator with Scalability for Human Body Heat Harvesting

The prosperity of intelligent wearables brings an increasingly critical problem of power supply. Regular rechargeable lithium or disposable button batteries have some problems, such as limited capacity, frequent replacement, environmental pollution, etc. Wearable energy harvester (WEH) can fundamentally solve these problems. Among WEHs, thermoelectric generator (TEG) is a promising option due to its independence of light condition or the motion of the wearer, and thermoelectric conversion (TEC) has the characteristics of quietness and continuity. Therefore, TEG has become a suitable choice for harvesting low-grade heat energy such as human body heat. Ionic thermoelectric gel (iTEG) has the advantages of a large Seebeck coefficient, freely defined shape and size, low processing cost, wide material sources, easy encapsulation, etc. In this paper, the gelatin-based iTEG is regulated and optimized by silica nanoparticles (SiO2 NPs). The optimal compound quantity of SiO2 NPs is determined, and the optimization mechanism is discussed through a series of characterization tests. Based on the iTEG, a kind of scalable flexible TEGs is proposed, and its preparation method is described in detail. A small wristband TEG (STEG) was made, and its Seebeck coefficient is 74.5 mV/K. Its bendability and stretchability were verified, and the impedance matching experiment was carried out. By charging a capacitor, the STEG successfully lights up an LED at a temperature difference (ΔT) of ~15.5 K. Subsequently, a large extended oversleeve TEG (LTEG) was prepared, and a set of heat sinks was added at the cooling end of the LTEG. Being worn on a volunteer’s forearm, the LTEG output a voltage of more than 3 V at ~20 °C. Through storing the converted energy in a capacitor, the LTEG directly drove a calculator without a DC–DC booster. The proposed iTEG and TEGs in this paper have the prospect of mass production, extending to people’s clothes, harvesting human body heat and directly powering wearable electronics.

An energy harvesting reactor for high voltage overhead insulated shield wires considering randomness of meteorological conditions

Harvesting energy from the insulated shield wire with tuning is expected to be a possible solution to the problem of high power supply for online monitoring devices on high voltage overhead transmission lines. However, the randomness of meteorological conditions, such as wind and temperature, may cause fluctuations in the energy harvesting system's power and voltage. This paper presents an integrated energy harvesting reactor with both tuning and transformer functions, which can also consider the randomness of meteorological conditions. The statistical confidence interval of equivalent circuit parameters is numerically calculated based on meteorological data collected along a transmission line for a whole year from 2016 to 2020. On this basis, a combined magnetic circuit for the energy harvesting reactor is proposed to achieve a self-adaptive negative-feedback regulation, and parameter optimization is carried out and validated by field-circuit coupled simulation. Finally, an energy harvesting reactor prototype is developed and tested. The statistical analysis results on the equivalent circuit parameters show that they are approximately subject to Gaussian distribution. Besides, it is found from the experimental results that the maximum power under rated equivalent circuit parameters is 935 W, and the maximum power can reach 800–1000 W within the fluctuation range of equivalent circuit parameters considering meteorological randomness. Overall, the experimental results of the harvested power varying with load resistance conforms to the simulation results. Furthermore, compared to using a deeply saturated tuned reactor, the energy harvesting reactor shows better robustness to the randomness of meteorological conditions and the total harmonic content of output voltage is reduced by 64%. Therefore, the proposed energy harvesting reactor for high voltage overhead insulated shield sires shows more potential for a practical application than the existing methods.

A New Method of Conductor Galloping Monitoring Using the Target Detection of Infrared Source

Because the galloping of iced conductors is one of the main disasters in the State Grid, resulting in huge economic and property losses every year, the research on relevant monitoring methods is of great significance. The existing galloping monitoring technology is mainly based on the contact detection method, which presents potential electrical hazards and power supply problems. In this paper, a conductor galloping monitoring method based on the target detection of infrared sources is put forward to overcome the shortcomings of existing methods. In other words, an infrared source label is installed on the conductor spacer, high-definition night vision infrared cameras are installed on electric power towers to take video of the infrared source labels, and the characteristic amplitude of conductor galloping is calculated by an image recognition and tracking algorithm. The practical application results indicate that the method has the advantages of non-contact detection, safety and reliability, and high detection accuracy.

Optimal design of energy-taking power supply based on AC electric field induction

AC electric field induction based energy extraction power supply is a new power supply method for the on-line monitoring device of transmission lines, but because of its low output power, it is difficult to meet the electricity demand of the on-line monitoring device. In order to solve this problem, a new induction electrode structure is proposed based on the theoretical analysis of the factors affecting the energy taking power, and the simulation analysis and experimental verification are carried out. The results show that the designed induction electrode can generate a displacement current of 3.35mA at 10kV voltage level, and the power output can be more than 600mW when the load resistance is greater than 5kΩ. The principle and method of this paper provide a new idea for solving the power supply problem of on-line monitoring device.

A Ring-Type Triboelectric Nanogenerator for Rotational Mechanical Energy Harvesting and Self-Powered Rotational Speed Sensing.

In recent years, sensors have been moving towards the era of intelligence, miniaturization and low power consumption, but the power-supply problem has always been a key issue restricting the popularization and development of machine-mounted sensors on the rotating machinery. Herein, we develop a ring-type triboelectric nanogenerator (R-TENG) that functions as a sustainable power source as well as a self-powered rotational speed sensor for rotating machinery. The R-TENG adopts a freestanding mode and consists of a ring-type container unit, an end cover and polytetrafluoroethylene (PTFE) cylinders. In this study, the influence of the number of cylinders, the PTFE cylinder’s diameter and the rotational speed on the electrical output are systematically examined, and the motion law of the PTFE cylinders in the container is revealed by the experimental results and verified by kinetic simulation. At a rotational speed of 400 rpm, the output voltage, current and transferred charge of the designed R-TENG reached 138 V, 115 nC and 2.03 μA, respectively. This study provides an attractive power supply strategy for machine-mounted sensors of the rotating machinery, and the rotational speed measurement test also suggests the potential application of the R-TENG as a self-powered rotational speed sensor.

Quantitative Influence of Wind Farm Reactive Power and Voltage Control Capability on Hunan Power Grid Thermal Power Spinning Reserve

Affected by factors such as the inverse distribution of power sources and loads in the province, and the mismatch between the construction of load center power sources and load growth, the problem of voltage stability in central and southern Hunan is prominent, which mainly restricts the thermal power maximum operating capacity of the Hunan Power Grid. Under the heavy load mode, the hydro power units and thermal power units operating in the province need to reserve a certain amount of spinning reserve to response the voltage stability problems in central and southern Hunan. Thus, it leads to insufficient power supply during peak load periods. In recent years, the grid load has maintained rapid growth, and the increase in power sources is mainly the wind power. Affected by the anti-peak-shaving characteristics of wind power, the lack of wind power has aggravated the problem of insufficient power supply. Actually, the wind turbine is in a hot standby state during standby/backup, and its grid-connected converter is still in a grid-connected state within four hours. Besides, the continuous running SVG in the wind farm booster station can still be used temporarily. The above devices can provide reactive power support to the power grid during the transient process. Therefore, this paper takes the southern Hunan region as an example, and quantified the reduced thermal power requirement reserve by analyzing the reactive power support effect of the grid-connected wind farms. In this way, the power supply capacity can be improved.

Оценка экономической целесообразности подключения удаленных потребителей восточной Арк­тики к энергосистеме

The article deals with the problem of power supply to remote consumers in the Eastern Arctic. The authors present a methodology for assessing the economic feasibility of connecting remote consumers to the power grid in comparison with power supply option from autonomous fossil or nuclear fuel based power plants. The methodology is focused on the analysis of consumers, the connection of which requires the construction of power transmission lines with a voltage of 35—220 kV. The authors give the results of assessing the feasibility of connecting promising enterprises for the development of deposits of the Chukotka Autonomous District: the Klen ore gold deposit, the Pyrkakayskie stockwork tin-tungsten deposit and the Amaam coal deposit. They consider three scenarios related to different periods of the tariff equalization mechanism in the Far Eastern Federal District. Estimates of the levelized electricity cost show that the construction of power transmission lines is economically feasible only with a reduced electricity tariff. If in 2028 the tariff equalization mechanism is canceled and an economically justified tariff begins to operate, then it is advisable to build autonomous power plants. The research results are summarized for the possibility of analyzing the feasibility of connecting remote consumers of the different Eastern Arctic regions to the power grid via power lines with a voltage of 35—110 kV under various technical options and economic conditions. The levels of electricity tariffs, fuel prices, and specific capital investments in the construction of small-scale nuclear power plants, at which the construction of 35—110 kV power transmission lines to connect consumers to the power grid is effective, are determined.

Energy Management Model of Intelligent Park Based on Improved Depth Deterministic Gradient Strategy Algorithm

The traditional distribution automation system, demand side management system, and distributed generation access and control system, respectively, solve the problems of regional distribution network power supply, customer power consumption, and new energy utilization to varying degrees. Intelligent Park evolved from the concept of intelligent park of State Grid Corporation, Modern enterprises, or residential areas that can make full use of modern communication, computer, automation, and other technologies to implement the power supply demand of the park. For the modern intelligent park with user-side temperature control load and demand response load access, an intelligent park energy management and optimal scheduling method based on deep reinforcement learning (DRL) algorithm is proposed. Through the interaction between the agent and the energy environment of the intelligent park, the control strategy is adaptively learned. This method can realize the continuous action control of energy management in intelligent park and can realize the optimal scheduling decision of intelligent park in various scenarios. Firstly, based on the characteristics and types of intelligent park aggregation unit, the environment model of intelligent park energy management system interacting with agent is established. Secondly, the basic principle of deep deterministic policy gradient deep algorithm is introduced, and on this basis, the key links of deep reinforcement learning algorithm, such as action space, state space, reward mechanism, neural network structure, and learning process, are designed. Finally, the effectiveness of the proposed algorithm is verified by an example of a city intelligent park.

Investigating the effects of wind concentrator on power performance improvement of crossflow wind turbine

Small wind turbines are efficient for solving power supply problems in remote off-grid regions. A crossflow wind turbine is a drag-based small vertical axis wind turbine, which is suitable for small-scale power generation in the built environment because of its low aerodynamic noise. However, the power performance of a crossflow wind turbine is generally lower than that of a Savonius wind turbine. Aiming at improving the performance of a crossflow wind turbine, this study develops a wind concentrator by adding two parallel plates with flanges, which is based on the “wind lens” concept, to an arc-shaped windshield, which is based on an existing concept of a flow deflection device for a crossflow wind turbine. The effects of adding two parallel plates with flanges to the windshield (i.e., the effects of the wind concentrator) on the performance of the crossflow wind turbine are quantified with wind tunnel experiments and analyzed based on the flow field characteristics obtained by computational fluid dynamics simulations. The experimental results show that the wind concentrator enhances the maximum power coefficient of the crossflow wind turbine by 108% from 0.12 (without wind concentrator/windshield) to 0.25 (with the wind concentrator), whereas the arc-shaped windshield improves it by 48% from 0.12 to 0.17 (with the windshield). The numerical simulations reveal that the main cause for the power performance enhancement is a downward deflection of the approaching flow to the upper part of the rotor because of a significant increase in the pressure level on the upwind side of the upper flange and an overall decrease in the pressure level in the wake of the wind concentrator. In conclusion, adding two parallel plates with flanges to an arc-shaped windshield is effective for significantly enhancing the power performance of a crossflow wind turbine.

Impact of the HFC migration to FTTH on the efficiency and reliability of the internet provider services business (A case Study)

This paper presents the impact on the efficiency, reliability, and quality of the Internet provider services due to the migration of the Hybrid Fiber Coaxial (HFC) to the Fiber To The Home (FTTH) infrastructure. The implementation of the emerging technology on communication caused an increase in the internet service provider business competition and it makes the company that engaged in this field will compete to provide the best service to the customers as especially on the efficiency and reliability of the services to whom using the FTTH. The comparison and analysis of the impact of the HFC stand-alone to the FTTH technology migration process on both of the customers sides as well as the Network Availability and the percentage of uptime (connection to the ISP’s) of customer devices are provided. In this case study, it is found that the infrastructure cost of the technology HFC system is cheaper about 53.93 percent than the technology FTTH system. However, from a reliability perspective, FTTH is much better than HFC. It is found that the impact of the migration from HFC to FTTH shows the yearly Network Availability was 98.635 percent with a downtime of 2,819,473 minutes. And it provides an increase of Network Availability after construction (during commissioning or acceptance test). In addition, it was found that the correlation between uptime/downtime before migrating during employed the HFC technology, there were many problems caused by power supply problems and high losses of the coaxial cable. So if the coaxial cable is replaced by the fiber optic cable, will be there is an increase in the availability of the Network Availability during 2020 by 1.301 percent. Also by takeout the FDT on the FTTH, it is predicted that the cost reduction about 10 percent, faster implementation for the schedule and fewer cables maintain.

Magnetoelectrical Clothing Generator for High‐Performance Transduction from Biomechanical Energy to Electricity (Adv. Funct. Mater. 6/2022)

Magnetoelectrical Clothing Generator In article number 2107682, Weilin Xu, Xiaoming Tao, Guangming Tao, Bin Su, and co-workers show scalable-manufactured flexible magnetoelectrical clothing that can convert mechanical energy generated by daily behavior into electrical energy required for electronic devices, solving the problem of continuous power supply of electronic clothing especially in harsh outdoor environments, and promoting sustainable development in wearable electronics.

METHODS FOR INVESTIGATING CONTRACTION CHARACTERISTICS OF A PART OF MUSCLES FOR IMPLANTABLE POWER GENERATION SYSTEMS

To develop a power generation system as a solution to the power supply problems of small active implantable medical devices, we proposed a new method to examine muscles using skeletal muscle contraction through electrical stimulation. Realization of the system requires data on the contraction characteristics of a part of the muscles through which blood flows; thus, a dedicated setup was built and verified using a goat. The connecting parts were attached to two points in the large muscle of the goat’s trunk; one was fixed and the other slid along the guide. The distance and force between the two points, approaching each other, were measured by contracting the muscle between the points using electrical stimulation and pulling the measurement cart. The contraction distance and force were measured simultaneously, and the dynamic work of the contraction was calculated. The muscle work occurred with almost the same time delay regardless of the load, and the work tended to be greater when the contraction force, and not the contraction distance, of the muscle was large. The setup is physiological, simple, and versatile. Our setup can potentially be used in the development of implantable power generation systems and in other related fields.

A Relative Humidity Sensor Based on Non-Adiabatic Tapered Optical Fiber for Remote Measurement in Power Cable Tunnel

To solve the power supply, signal communication, and lifetime problems in the humidity sensing in power cable tunnel, an intrinsic non-adiabatic tapered optical fiber (NATOF) relative humidity (RH) sensor without functional film was proposed in this article. The sensing principle based on multimode interference and refractive index (RI) sensitivity was introduced. The relationship between humidity sensitivity and the waist diameter of NATOF was theoretically analyzed to improve the sensor sensitivity. It is found that high relative humidity sensitivity detection can be achieved by taking advantage of the NATOF’s high sensitivity near the dispersion turning point (DTP). The test-obtained trends of the humidity sensitivity at different waist diameters were consistent with the theoretical results. The proposed NATOF sensor with a waist diameter of 2.39 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> had a linear response in the range of 35%–90% RH, a detection distance of over 10 km, a relative humidity sensitivity of −47 pm/% RH, and an accuracy of ±4.6% RH. Based on the different response sensitivities to humidity and temperature of different dips, a sensing matrix was established to solve the temperature cross-sensitivity issue of the relative humidity sensor.

A hybrid energy harvesting system for self-powered applications in shared bicycles

The public transportation system is highly integrated into peoples' lives, and the emergence of shared bicycles solves the problem of the last mile of travel. The shared bicycle is equipped with the necessary low-power consumption components, which require a continuous power supply scheme. In this paper, to solve the power supply problem of low-power components on shared bicycles, a hybrid energy harvesting system is designed, modeled, and tested. The proposed system includes three modules: kinetic energy input module, power generation module, and energy storage module. The energy input module is the rotational kinetic energy transferred from the chain to the rear wheel when the shared bicycle is being ridden. The power generation module utilizes the magnet array installed on the spokes to cut the magnetic lines of induction and deforms the piezoelectric sheet to harvest the kinetic energy of the wheel. The energy storage module is used to store the current generated by the two harvesters that have passed through the rectifier circuit. The proposed hybrid energy harvesting system is analyzed through theoretical modeling and simulation, and the power output of the collector is calculated through experimental data. The peak voltage and RMS voltage of the hybrid energy harvesting system are 25 V and 7.18 V, respectively. Experiments verify that the proposed hybrid energy harvesting system is feasible for powering low-power components on shared bicycles.

System of the Autonomous Lighting of Railway Objects

Railways run throughout Russia. There are sections of roads where centralized power supply lines are located far away or absent. It is difficult to regulate and ensure traffic safety at the sufficient level on such sections at the intersection of roads and railways at the same level. (Research purpose) The research purpose is to analyze the equipment available on the Russian market, powered by renewable energy sources, to solve the problem of guaranteed power supply to remote railway infrastructure objects and to select the most promising types, the effectiveness of which depends on natural and climatic conditions. (Materials and methods) The article presents a power supply system that can be applied to various artificial and engineering structures of general-purpose railway transport, such as crossings, bridges, tunnels, crossings in front of bridges and tunnels, sidings and others, for emergency or on-duty lighting. Such a system allows you to save electricity coming from a centralized power supply system, and in the case of an emergency shutdown, to provide power supply to the facility for a long time, and perform the function of backup power supply, but it takes on special importance in places where there are no centralized networks, when using it as an autonomous power supply system. (Results and discussion) The article presents a classification according to the categories of autonomous power supply systems, criteria of importance and power consumption of the objects, and gives the conditions for their use. The article describes a block diagram of the power supply system of a pedestrian crossing over a single track with energy reservation for up to three days. The daily energy consumption of a railway pedestrian crossing with lighting and railway traffic lights, installed the energy capacity of batteries with redundancy for up to three days, the power and number of photovoltaic converters are calculated. (Conclusions) An example of an autonomous lighting system for a railway pedestrian crossing with established technical parameters of equipment showed the social and economic efficiency of its application.

Validation of GPS-Based Monitoring and Remote Sensing of Ice-Shelf and Ice-Sheet Movement Changes.

The north and south poles of the earth (hereinafter referred to as the polar regions) are important components of the earth system. Changes in the material balance and movement of the polar ice shelf reflect the influence of the polar regions on global climate change and are also a response to global climate change. Through a comprehensive investigation of ice-shelf kinematics, with sufficient accuracy, it is possible to obtain ice-shelf elevation, movement-state data, ice-shelf material balance state, and the ice-shelf movement dynamics mechanism. Due to the extremely harsh environment in polar regions, remote sensing is currently widely used. Manual and equipment monitoring methods show insufficient accuracy or discontinuous time series. There is an urgent need to obtain continuous real-time ice-shelf kinematics-related parameters on the ground to verify the reliability of the parameters obtained by satellite remote sensing. These parameters should be combined with remote sensing monitoring to provide data support. In this paper, a monitoring system for the movement of polar ice and shelf ice cover is developed, and it is proposed that various data can be acquired by integrating high-precision GPS (global positioning system) and other sensors. Solutions to the problem of low-temperature power supply in the polar regions, data acquisition and storage strategies, and remote communication methods are proposed. Testing and remote sensing validation verified that the developed acquisition system can fulfill the requirements for monitoring the movement of the polar unmanned ice shelves and ice sheets.

Broadband rotary hybrid generator for wide-flow-rate fluid energy harvesting and bubble power generation

The ocean contains copious available natural resources and energy. Ocean in situ power generation technology, directly harvesting energy from ocean fluids, is the crux of solving the problem of power supply for eupelagic or deep-sea exploration equipment. However, the ultralow frequency and wide-flow-rate characteristics of ocean fluids have brought severe challenges to in situ power generation in the ocean. In this paper, we develop a broadband rotary piezoelectric-electromagnetic hybrid generator to effectively harvest the energy of wide-flow-rate and ultralow frequency fluids. By using rotational torque to directly drive deformation of piezoelectric films, the hybrid generator effectively collects extremely low-speed rotational energy (as low as 0.01 Hz), with the efficiency and speed of energy conversion of the piezoelectric component of the generator being respectively 8.2 times and 60 times higher than that of a traditional piezoelectric cantilever beam harvester. The integration of the electromagnetic component further improves the energy harvesting performance of the generator over a wide flow velocity range. Compared with existing energy harvesters, the water-driven power generation per unit flow rate is enhanced by a factor of 75.5. The output power density of the proposed underwater bubble power generation system using the hybrid generator is 287 mW/m3, which is 275 times higher than previous devices. This work provides a viable approach to blue energy exploitation, especially ocean in situ power generation, and opens up many prospects for underwater cable-free power supply to eupelagic or deep-sea equipment.

Research on the New Topology and Coordinated Control Strategy of Renewable Power Generation Connected MMC-Based DC Power Grid Integration System

The modular multilevel converter (MMC) station connected to the islanded renewable energy generation system needs to adopt the voltage frequency (VF) control to provide AC voltage. The single-pole converter fault will unbalance the input and output power of the DC power grid, which causes the DC voltage or the bridge arm current of the non-fault pole to exceed the protection value in the time scale of tens to hundreds of milliseconds, leading to cascading failures. To realize the fault ride-through (FRT) of single-pole converter fault, this paper analyzes the electrical characteristic of the system. Based on the analysis, the existing topology is optimized and the reasonable operation reserved margin is designed. Furthermore, the corresponding control strategy is proposed, which can not only ensure the single-pole converter block fault ride-through but can also realize economic, stable, and resilient power supply and address asymmetrical problems. Finally, the simulation model is built in PSCAD/EMTDC and the simulation results validate the effectiveness of the proposed control strategy.

Capacity optimization of hybrid energy storage system for flexible islanded microgrid based on real-time price-based demand response

The islanded microgrid (IMG) is universally accepted as an important method to solve the island power supply problem. The optimal capacity of the hybrid energy storage system (HESS) is necessary to improve safety, reliability, and economic efficiency in an IMG. To improve the IMG ability to deal with uncertainty, this paper proposed a flexible islanded microgrid (FIMG) model with real-time price (RTP)-based demand response (DR). Through RTP to guide users’ electricity consumption behaviors more in line with renewable energy sources (RES) output law, the capacity allocation of the HESS was optimized and the system had sufficient flexibility in each scheduling period. In this paper, two decision variables of the HESS, the number of lead-acid batteries and supercapacitors, were determined based on the objective of comprehensive operating cost (COC) and flexibility insufficiency rate (FIR) minimization. Firstly, the non-dominated sorting genetic algorithm II (NSGA-II) was devoted to obtaining the Pareto set that satisfies the FIMG day-ahead scheduling. Then, both the loss of produced power probability (LPPP) and the loss of power supply probability (LPSP) corresponding to each Pareto solution were gotten based on the real-time dispatch strategy. Finally, taking COC, FIR, LPPP, and LPSP as evaluation indicators, the improved Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) was applied to select the optimal solution from the Pareto set. In the case study, a FIMG on an island in Guangdong province was analyzed and discussed. By studying typical days in winter and summer of the FIMG, the superiority of the proposed model and methods was verified.

Nuclear power in Russia’s national projects

Population supports the need for switching to green power, which is most often understood to mean the use of solar and wind energy. It would be however a mistake to think that solar and wind power plants will solve in full the problem of uninterrupted power supply for all sectors of economy due to the instability of generation modes and the scale of such energy production. Experts suggest that the only possible way to address global energy and environmental issues is further evolution of nuclear power. Nuclear power is not listed explicitly as a national priority project but it is a component of the Science national project and is expected to contribute to the implementation of the Ecology, Education, and International Cooperation and Export projects. In the context of the Ecology project, nuclear power is capable to play a key role in preventing environmental contamination. In the framework of the International Cooperation and Export project, it is possible to export high-technology fast neutron reactors. The experience of interaction with the interested public, and the developed and implemented occupational training programs will provide for the shaping of radiological literacy among young people as part of the Education project.