Basic Power Research Articles

Thermo-economic assessment of upgrading a basic gas turbine power plant into CHP plant

Thermo-economic assessment of upgrading a basic gas turbine power plant into CHP plant

Thermo-economic assessment of upgrading a basic gas turbine power plant into CHP plant

Thermo-economic assessment of upgrading a basic gas turbine power plant into CHP plant

Application Research on Zero Output of Double Low Pressure Cylinder of 600MW Unit

Under the dual carbon target, the rapid development of new energy promotes the increasing peak shaving capacity of thermal power units as basic power sources. Taking 600MW unit as an example, this paper studies the feasibility of zero output of low pressure cylinder for heat supply transformation of 600MW unit, and analyzes the peak shaving capacity of the unit by cutting off double low pressure cylinder and single low pressure cylinder.

WI-FI-BASED CHANNEL STATE INFORMATION APPROACH FOR SENSING AND HUMAN WALKING ACTIVITY RECOGNITION IN INDOOR ENVIRONMENT

Many studies have demonstrated that Wireless Fidelity (Wi-Fi) networks can detect human behavior due to the development of wireless devices and detecting methodologies. Human activity recognition applied Channel State Information (CSI) in commercial Wi-Fi devices, which has many practical applications. This paper aims to present a method for recognizing human activity that uses enhanced Wi-Fi-based CSI signals. At first, researchers examined how various perceptive antennas detect motion caused by humans. The proposed algorithm for selecting antennas considers the sensitivity of each antenna concerning the task at hand. Long short-term memory (LSTM) and Inception Time-based classification model was developed and fine-tuned for experiments. This study also suggested two basic power methods to retrieve the effective interval associated with human activity, one of which can solidify the active signals while weakening the inactive signals. Last but not least, an algorithm has been developed for segmenting activity to identify initiation and termination times. An efficient outliers removal technique was used to remove the edges. The results show that using commonplace Wi-Fi routers can accurately categorize human actions 87% of the time. To validate and evaluate these methods, immense experiments were conducted in exquisite indoor environments. As demonstrated by experiments, the proposed methods can mitigate the disturbance caused by inert and non-responsive signals and enhance accuracy rates while improving efficiency and processing time.

Social pathologies of informational privacy

Social pathologies of informational privacy

Electric vehicle charging station modelling using FOH approximation and material selection based on temperature

In this article analytical model of New Energy Charging Station for vehicle is derived. It creates a nonlinear closed loop, when power electronic devices are connected to Grid due to the interaction with the grid’s impedance. It is particularly concerning because the prevalence of such devices, such as massive EV charging stations, distributed generation, distributed storage and APFs, is predicted to grow.. Furthermore, fast variable closed-loop dynamics are also illustrated when it comes to APFs. The primary contribution of this study is that it use DQ-theory to transform a closed loop (non-linear) into a closed loop of LTI. A straightforward, DT-controlled APF connected to a basic power source is used to test this technology in the beginning, producing a group of LTI differencial equations with easily determinable transient and stability response. Furthermore, the method may be done to a wide range of APFs linked to any power system with ease. It is finally validated using MATLAB/Simulink. The main objective is to develop a simplified model that ignores potential instability caused by nonlinear feedback loop and this can be used to examine the stability of the system using the developed model.

Design islanded hybrid micro-grid and analyzing its socio-economic technical and environmental aspects for off-grid electrification in developing countries

Developing countries are facing many electricity crises such as low production, worst power outages, blackouts, and poor inadequate supplies. Most of their rural areas have no basic power infrastructure as it requires long transmission lines, which causes high installation, operation, maintenance costs and line losses issues. The people of these unconnected rural areas belong to low-income families and use kerosene oil, candles, small solar panels, and batteries to meet their basic electricity needs. As an alternative, renewable-based hybrid energy systems have enormous potential. It is also environmentally friendly and low-cost, sustainable, and promising solution to electrify rural off-grid areas. This research work focuses on the economic and optimal design of a renewable-based hybrid energy system for the rural off-grid area of Pakistan. HOMER (Hybrid Optimization of Multiple Energy Resources) software is used to perform techno-economic and environmental analysis. The optimization results show that the most economical and optimal configuration is PV/diesel generator with batteries having lower harmful emissions. Furthermore, the sensitivity analysis is performed to refine the results which show that the most optimal system will remain sustainable if variations occur in the sensitivity variables in the future. Moreover, the results and findings of this study can help the government to make effective policies and planning to provide reliable and affordable electricity to the off-grid areas, to improve the electrification rate in the country.

Construction and application of natural stable isotope correction matrix in 13C-labeled metabolic flux analysis

Stable isotope 13C labeling is an important tool to analyze cellular metabolic flux. The 13C distribution in intracellular metabolites can be detected via mass spectrometry and used as a constraint in intracellular metabolic flux calculations. Then, metabolic flux analysis algorithms can be employed to obtain the flux distribution in the corresponding metabolic reaction network. However, in addition to carbon, other elements such as oxygen in the nature also have natural stable isotopes (e.g., 17O, 18O). This makes the isotopic information of elements other than the 13C marker interspersed in the isotopic distribution measured by the mass spectrometry, especially that of the molecules containing many other elements, which leads to large errors. Therefore, it is essential to correct the mass spectrometry data before performing metabolic flux calculations. In this paper, we proposed a method for construction of correction matrix based on Python language for correcting the measurement errors due to natural isotope distribution. The method employed a basic power method for constructing the correction matrix with simple structure and easy coding implementation, which can be directly applied to data pre-processing in 13C metabolic flux analysis. The correction method was then applied to the intracellular metabolic flux analysis of 13C-labeled Aspergillus niger. The results showed that the proposed method was accurate and effective, which can serve as a reliable data correction method for accurate microbial intracellular metabolic flux analysis.

Spatial-temporal characteristics and influencing factors of county-level carbon emissions in Zhejiang Province, China.

Zhejiang Province is a "demonstration area for high-quality development and construction of common prosperity" in China. Moreover, the county is the basic unit and power source for the economic development of Zhejiang Province. Therefore, the research on the spatial-temporal characteristics and influencing factors of county-level carbon emissions is of great significance for Zhejiang Province to achieve the strategic goal of carbon peak and carbon neutrality. Based on the carbon emissions and socio-economic data of 62 counties in Zhejiang Province from 2014 to 2020, the spatial dependence and agglomeration of county-level carbon emissions are analyzed through the spatial autocorrelation test and local spatial autocorrelation test respectively. According to the spatial-temporal characteristics of county-level carbon emissions revealed by the index of Moran's I and local Moran's I, the spatial error STIRPAT model is used to study the influencing factors of county-level carbon emissions in Zhejiang Province, China. The main results are as follows: (1) The total amount of county-level carbon emissions of 62 counties fluctuates from 259.69 to 326.28 million tons and shows a growth trend. (2) Moran's I index is between 0.369 and 0.399. The county-level carbon emissions have a significant spatial correlation, and the spatial agglomeration trend is relatively stable, which is consistent with the hypothesis of the geographical polarization effect. (3) High-high agglomeration counties are concentrated in the northeast of Zhejiang Province, while low-low agglomeration counties are mainly in the southwest. (4) The relationship between county per capita GDP and carbon emissions has not been "decoupled," because when other variables remain unchanged, the county's total carbon emissions will increase by 2.866% for every 1% increase in the county's per capita GDP; the increase of the proportion of secondary industry contributes to the decline of carbon emissions, and the low-carbon effect brought by large-scale industrial development as well as scientific and technological innovation has not yet appeared. (5) The estimate of the spatial coefficient λ was 0.324, which illustrates that the carbon emission of a single county is positively affected by the carbon emission of the neighboring counties, and other socio-economic factors affecting carbon emission among counties also have a spatial correlation. Therefore, the policy of realizing regional coordinated development as well as the carbon peaking and carbon neutrality goals should not only focus on industrial layout, but also take a dynamic and comprehensive consideration from a spatial perspective.

Novel dynamic equivalent circuit model of integrated energy systems

With the transformation from individual energy systems to integrated energy systems (IES), equivalent circuit IES modeling is developed to represent the heat and electricity consistently for coordinated analysis, control and optimization. However, physical properties of equivalent parameters are a mismatch, and the key operation characteristics, including dynamics and coupling, have not yet been fully described, remaining obstacles for optimal electricity-heat coordination. In this study, a novel IES equivalent circuit modeling methodology is proposed. From the perspective of physical characteristics, the similarity of heat transfer and micro conductivity processes is determined. A novel thermoelectric equivalent rule with matched energy units is proposed, showing the corresponding relations of the basic state, power, and energy quantities between electricity and heat. Then, the equivalent rule is applied in IES equivalent circuit modeling, where the equivalent heat element models are established to characterize the electrothermal coupling and dynamics of heat subsystems. Finally, following the IES system structure, the IES equivalent circuit model is completed. A numerical comparison is performed to verify the effectiveness of the model. The simulation results demonstrate that the proposed model can fully capture the dynamic and coupling characteristics of IES.

Socio-culture of Youths: Impact of Personal Values towards Effective Communication

Understanding the sociocultural context of youths; personal values, will give direction in planning communication strategies and initiatives to motivate participation of youths. In addition, it will give insights to youths preferred tools, medium, design and approach for communication. This study aims to understand the personal values that are being upheld by youths in Malaysia, and identify the effective communication medium that is aligned to their personal values. The objectives were attained through systematic review of secondary data available in open sources platforms, published between the years 2017-2021. Thematic analysis was done using Atlas.Ti followed by an expert focus group discussions (FGD) to validate the findings. Among the main personal values that are upheld by youths in Malaysia from the 10 Basic Human Values Theory (BHV Theory), are hedonism, self-direction and power. Secondary findings from this study shows that youths in Malaysia use social media as their main communication preference platform i.e., WhatsApp, Instagram, Twitter and TikTok. Personal values influence social media preference, in terms of platform, design and approach with characteristics i.e., affordability (most are free of charge), ease of use, control, and having personalized and customization features. Social media enables them to interact, collaborate, entertain, stay connected, and voice out.

Research on Financial Strategy and Financial Capability of Grassroots Power Supply Enterprises Based on Stochastic Matrix Model

On the basis of the generation, evolution, and development of the basic power supply enterprise’s financial core competence, this article determines the connotation and essence of the basic power supply enterprise’s financial core competence, so as to play a guiding role in fully and correctly grasping the basic power supply enterprise financial core competence. This article focuses on the formation mechanism and factors of the financial core competence of grassroots power supply enterprises and reviews the latest research hotspots and their theoretical significance in academia. By applying the random matrix model to evaluate the core financial capabilities of grassroots power supply enterprises, it proposes a path for cultivating and improving the core financial capabilities of grassroots power supply enterprises. Through a detailed and powerful discussion, it is possible to effectively improve the financial management efficiency of grassroots power supply enterprises and quickly adapt to the needs of market changes, so as to meet the interests of relevant stakeholders of grassroots power supply enterprises as much as possible. Considering the market competition environment, it is found that the positive relationship between corporate responsibility information disclosure and the degree of earnings management is only significant in low-competitive markets, which also shows that with the intensification of market competition, the degree of information asymmetry decreases. The ability of power supply is also increasing, which will weaken the mechanism of grassroots power supply enterprises to conceal earnings management behavior through corporate responsibility information disclosure. The results show that corporate responsibility information may become a tool to cover up the management of grassroots power supply enterprises to manipulate earnings and reduce the quality of earnings reports, and this behavior will be different in grassroots power supply enterprises with different characteristics and external environments. This will help to form an objective understanding of corporate responsibility information disclosure behaviors, identify the motives of grassroots power supply companies’ responsible behaviors for regulators, standardize corporate responsibility disclosure norms, and take differentiated measures for different situations.

Comparison of results and calculation speeds of various power system power flow methods

The theoretical part describes basic power flow methods Gauss-Seidel and Newton-Raphson in their practical forms for solving a load flow problem. In practical part, IEEE test 24, 48 and 72 node networks are used to compare basic methods in terms of calculation speed: on execution of one iteration, entire calculation and on given accuracy influence. Also is analyzed optimal acceleration factor for Gauss-Seidel method and convergences of methods. On the end, final conclusions are obtained after analyzing comparison results.

Improvement in interfacial stability of high-rate Ni-rich oxide cathode by multifunctional LiTi0.5Zr1.5(PO4)3 conductive buffer layer

With the advent of the double carbon era, Ni-rich layered oxides with high energy density have become ideal cathode materials to support and secure the energy transition of basic power and transportation. However, with the increase in Ni content, Ni-rich layered oxides suffer from several problems, such as difficult precursor synthesis, structural instability, and high interfacial activity. In this study, a design scheme of uniformly coating LiTi0.5Zr1.5(PO4)3 (LTZP) conductive buffer layer on the outer surface of LiNi0.8Mn0.1Co0.1O2 (NCM811) grains was proposed to overcome the above problems. The results of first-principles calculations and various ex-situ characterizations showed that the NASICON-type LTZP material had excellent compatibility with the NCM811 material. The LTZP surface-modified NCM811cathode material presented outstanding electrochemical performance. The initial discharge specific capacity was 210.16 mAh g−1 at 0.2C, and a remarkably high discharge capacity of 147.68 mAh g−1 was recorded at 10C. The capacity retention rate reached 84.7% after 200 cycles of 1C (25 °C). This work presents a strategy for stabilizing the interface with a conductive buffer layer to enhance the electrochemical performance of Ni-rich cathode materials.

Size-dependent and nonlinear magneto-mechanical coupling characteristics analysis for extensional vibration of composite multiferroic piezoelectric semiconductor nanoharvester with surface effect

We study the extensional vibration of composite multiferroic piezoelectric semiconductor (PS) nanoharvester driven via a time-harmonic magnetic field. A theoretical analysis about working performances of device is performed based on zero-order plate equations with surface and nonlocal effects, consisting of a nonlinear magneto-mechanical coupling constitutive model for giant magnetostrictive material Terfenol-D and a linear phenomenological theory of PS material ZnO. Numerical results indicate that the basic bahaviors (including resonant frequency, bandwidth characteristic, magneto-electric (ME) coupling effect, output power and energy conversion efficiency) of the nanoharvester, can be dramatically improved through circuit types, semiconduction, external magnetic field, pre-stress and surface effect. This work is essential and crucial for understanding the size-dependent and nonlinear mechanical behaviors of multiferroic PS nanodevices under the extremely complex magnetic field and pre-stress field environments.

Model-Free Predictive Power Control for PWM Rectifiers under Asymmetrical Grids

Conventional model predictive power control (MPPC) features a simple concept and quick dynamic response. However, it relies heavily on the system model and its parameter accuracy. Furthermore, the steady ripples are still high due to the use of one voltage vector during one control period. Recently, model-free predictive current control (MFPCC) has been proposed in the current control of PWM rectifiers. Despite the strong parameter robustness, the principle of MFPCC cannot be directly applied to power control, because the relationship between power and converter voltage is more complex. This paper first proposes a basic model-free predictive power control (MFPPC), which successfully extends the principle of MFPCC to power control. Subsequently, an improved MFPPC is proposed, which uses an extended finite control set of voltage vectors to improve the steady-state performance. Furthermore, by using the online updated ultralocal model of PWM rectifiers, the problem of stagnant power updating in basic MFPPC is solved. The ideal three-phase grid voltages are symmetrical and sinusoidal, but the actual grids are usually unsymmetrical. In this paper, the proposed method is extended to asymmetrical power grids by adding an appropriate compensated power to the original power references. The proposed basic MFPPC and improved MFPPC are compared to conventional MPPC. The presented experimental results confirm the effectiveness of the proposed methods.

საბაზისო თბოელექტროსადგურებით ელექტროსისტემის სიმძლავრის რეგულირების ამოცანა

In the electricity systems, which have a large share of seasonal hydropower plants in the total production of electricity and do not have a developed structure of maneuvering power units running on organic fuels, it is necessary to use basic power plants to regulate the system capacity (load) on a daily basis. For the optimal solution of this task, the authors of the article have proposed a formula by which it is possible to estimate the monetary costs in different scenarios of power system management. It takes into account the pricing of electricity generated by imported and locally generated thermal power plants and sets out the main requirements for the efficiency and regulation range of thermal power plants, the satisfaction of which saves funds at the expense of reducing electricity imports.

2 n -Way Wideband Filtering Power Dividers With Good Isolation Enhanced by a Modified Isolation Network

In this article, a class of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{n}$ </tex-math></inline-formula> -way wideband filtering power dividers (FPDs) is presented and designed with a wide isolation band. It consists of ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{n}-1$ </tex-math></inline-formula> ) two-way power-dividing units and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$n$ </tex-math></inline-formula> three-line coupled lines. The basic two-way power divider is achieved by replacing a simple isolation resistor of the conventional Wilkinson power divider with a modified isolation network, so as to improve the bandwidth of better-than-20-dB isolation band from 40% to 120%. The modified isolation network is composed of one quarter-wavelength coupled line, two quarter-wavelength transmission lines, and one resistor. The three-line coupled line is introduced at each output of the proposed FPD to improve its frequency selectivity and passband bandwidth. Furthermore, after placing one additional isolation resistor on each three-line coupled line, the number of output ports in the proposed power divider could be doubled without introducing more two-way power-dividing units. Finally, a prototype two-way and two prototype four-way wideband FPDs with different occupied sizes are designed and fabricated. The feasibility of the proposed design method is verified by the good agreement between the simulated and measured results.

Capacitive Power Transfer With Series-Parallel Compensation for Step-Up Voltage Output

In this article, a basic capacitive power transfer topology with series-parallel compensation is developed for load-independent step-up voltage output. There are three main contributions. First, the step-up constant-voltage (CV) output and zero-phase angle property are designed by using an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h</i> -parameter modeling method. Second, a current-source rectifier is proposed at the secondary side and the working transient is analyzed. Third, the impact of parasitic resistances is investigated, and the output voltage attenuation and system efficiency are analyzed at different loads, coupling coefficients, and quality factors. A 130-W prototype is implemented with 150 × 300-mm metal plates. Experiments validate the CV output property with a step-up voltage gain of 2. The peak efficiency is 86.6% at a coupling coefficient of 0.16 and a transfer distance of 4 mm.

Analysis and Design of Two-Stage Cascaded LED Load Wireless Power Transfer System

This paper proposes a two-stage cascaded wireless power transfer (WPT) system aimed at increasing the transfer radius and supplying power to multiple low-power loads. The proposed WPT scheme is regarded as a cascading of two WPT systems. The system realizes constant current power supply for two-stage LED load and put emphasis on solving the problems of limited power supply radius and power supply of multiple constant current/voltage loads in WPT system. Four basic power supply types of transmission network are discussed in this paper, and the compensation network structures and parameters suiting for these types are determined by analyzing every stage’s input and output characteristic using two-port network T matrix. The result of research validates that constant current is achieved in general. Moreover, the two stage’s maximum efficiency is 68.04% when the LED total number changes from 6 to 13, which proves the feasibility of the proposed scheme.