bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Different Control Strategies in Pumping Mode of Variable-speed Pumped Storage Unit
Authors: Li Mengjia , Jiang Ningqiang
Published: December 2023

Because of the complex structure, the variable-speed pumped storage (VSPS) unit would face more stability problems in operation compared with conventional generators in the power grid. To overcome the shortcomings of the PI controller, the fractional order PI (FOPI) controller is applied for VSPS in pumping mode. To compare the quality of the two controllers, the WSCC 9-bus system with VSPS is studied under different disturbances. The dynamic performance is evaluated by calculating the integral of time multiplied absolute error criterion (ITAE) of rotor speed and active power of the stator. The result shows that the FOPI control strategy can effectively improve the dynamic performance of VSPS.
Low-carbon Optimization of Distribution Networks under the Consideration of New Energy Integration
Authors: Li Qiang , Jiang Yan , Du Changyu , Zhou Hangyu , Chen Tongxuan
Published: December 2023

Under the background of proposing the dual carbon target and building a new power system, distributed energy and energy storage are widely connected to the distribution network, and how to use distributed energy to realize low-carbon optimization of the distribution network needs to be studied urgently. This paper firstly analyzes the computation method of carbon emission flow from distribution networks and then establishes a node carbon potential model of the energy storage element and a low-carbon optimization model of distribution networks aiming at minimizing carbon emissions. Finally, it is verified through examples that new energy access can promote the low-carbon optimization of distribution networks.
Power Quality Disturbance Detection Based on Partitioning-Improved Empirical Wavelet Transform
Authors: Zhou Ke , Jin Qingren , Mo Zhiyue
Published: December 2023

Power quality is an important indicator to measure the quality of power supply in power grids. With the large evasion accession of new energy sources, its randomness and volatility cause frequent transient power quality problems in power grids. With the large evasion accession of new energy sources, its randomness and volatility cause frequent transient power quality problems in power grids. Aiming at the detection of transient power quality disturbance, this paper proposes the empirical wavelet algorithm which improves the adaptive division. This paper improves the spectrum processing, frequency point selection and frequency band division to improve the adaptive division ability of the algorithm under complex perturbation signals. Combined with the Hilbert transform, a perturbation detection algorithm is proposed based on an improved empirical wavelet algorithm to extract the transient characteristics of the perturbation signal. Through software simulation, this method has good adaptive ability in the face of composite power mass transient disturbance and can accurately extract the transient characteristics of the signal.
A novel network training approach for solving sample imbalance problem in Photovoltaic power prediction
Authors: Xian Zikang , Zhu Jianbin , Li Hanhong , Yin Yiding , Meng Anbo , Liu Jiawei
Published: December 2023

Randomness and intermittency are crucial challenges in photovoltaic (PV) power prediction. Most studies concentrate on addressing the randomness of PV power, and tend to overlook the intermittency that leads to sample imbalance, which negatively affects prediction accuracy. To address the sample imbalance, a novel approach called segment imbalance regression (SIR) is proposed. The SIR method proactively exploits the inherent imbalanced nature of samples by investigating the interactions among neighbouring samples, which leads to dynamical assigning weights. Through focused training and segmental prediction, SIR selectively retains the outside information while focusing segment inside, which enhances the gradient descent process and ultimately leads to improved training performance. With crisscross optimization (CSO), SIR demonstrates its performance sufficiently with an average RMSE reduction of 21.17% and 40.76% in the multi-step prediction and day-ahead prediction cases, respectively.
Evaluation and prediction of the life of vulnerable parts and lithium-ion batteries in electrochemical energy storage power station
Authors: Shao Jian , Sun Lei , Guo Dongliang , Xiao Peng , Yin Kangyong
Published: December 2023

The widespread application of renewable energy technology and changes in energy structure has led to changes in the structure and operation of traditional power grids. Electrochemical energy storage systems have gradually achieved commercial operation due to their high energy density, efficient energy conversion, and renewability. This article proposes a life assessment plan for vulnerable parts, conducts statistical analysis on the life data of vulnerable parts, and provides calculation methods for average life, reliability, and reliable life. Then, the residual capacity of lithium-ion is estimated by using electron dispersion spectroscopy, and a dual exponential capacity decay model is established. Finally, the residual life of lithium-ion is estimated through an extended Kalman filter, and the capacity attenuation trend is better captured by combining with Monte Carlo sampling to improve the accuracy of the remaining useful life of lithium-ion.
Research on Optimal Configuration of Integrated Energy Storage for Source Network, Load Storage Considering Carbon Emissions
Authors: Zhan Zhiguo , Zhang Lin , Song Zhiqiang , Li Sicheng , Zhang Zaiyi , Yang Zhuo , Zhao Shilin
Published: December 2023

This study endeavors to construct an optimized operation model for a Combined Heat and Power Microgrid that utilizes renewable distributed power generation. The model decouples the thermoelectric connection via energy storage equipment and takes into account carbon emissions based on multi-energy complementarity. This approach offers an optimization space for the thermal and electrical production of microgrids. Numerical simulation verification demonstrates that the optimization strategy proposed in this study enhances the flexibility of the system’s energy supply and improves the operational economy. Furthermore, the study explores the optimal storage battery capacity under the integration of a specific area’s source-grid-load-storage.
Coordinated Control Strategy for System of Hydrogen Production from Renewable Energy Considering Regulating Characteristics of Electrolyzers
Authors: Guo Xiaolong , Kang Pengpeng , Zhang Jiangfei , Song Pengfei , Yang Guixing
Published: December 2023

As a low-carbon and clean form of energy development and utilization, renewable energy hydrogen production technology has received widespread attention. However, under traditional control strategies, the electrolyzers are generally operated at rated power, and their ability to participate in the system of hydrogen production from renewable energy and grid regulation is not fully utilized. Therefore, this article proposes a coordinated control strategy for the system of hydrogen production from renewable energy that considers the regulation characteristics of electrolyzers. Firstly, models of each unit are established, and based on this, the working characteristics of the electrolyzer are analyzed through electrolyzer model simulation. Then, control strategies for each unit were designed, and the additional response control module is added to the control strategy of the electrolyzers to alleviate the fluctuation of DC bus voltage. Finally, through analysis, this coordinated control strategy has been proven to be effective.
Independent Energy Storage AGC Instruction Allocation Method and Control Strategy Based on Typical Scenarios
Authors: Liu Mingyi , Cao Xi , Sun Zhouting , Lei Haodong , Cao Chuanzhao , Pei Jie , Li Xizhe , Yang Yinting , Zhang Jianfu
Published: December 2023

The large-scale new energy sources such as solar and wind energy bring challenges to system frequency regulation. With the recognition of new energy storage as an independent market entity, it is necessary to study how independent energy storage can participate in automatic generation control (AGC) command mode and control with other generators. Firstly, this paper introduces the regulation range, upper and lower regulation characteristics, and requirements of energy storage and conventional units. Secondly, the AGC control unit’s response curve to AGC instructions is reasonably simplified for calculating benefits for each entity. Then, the AGC command distribution method based on the available frequency regulation capacity is established, and an AGC control mode suitable for independent energy storage power stations is proposed to maximize the frequency regulation mileage revenue. Finally, based on three typical AGC scenarios: continuous down regulation response, continuous up regulation response, and fluctuation of up and down regulation response, four schemes—only conventional units, priority call for independent energy storage, call for energy storage based on available frequency regulation capacity, and joint frequency regulation are compared, verifying the effectiveness of the model proposed.
Investigation of Gas-liquid Separation Experiment of Electric Pump Drainage and Gas Extraction Unit in High Gas-liquid Ratio Gas Wells
Authors: Zhang Bao , Jing Hongtao , Tu Zhixiong , Cui Hangbo , Bai Xiaofei , Zhou Huaiguang , Yu Xiaotong , Fan Dabin , Xue Longlong , Liu Taochou
Published: December 2023

Given the prominent problem of water in the Tarim basin of China with high formation temperature and large water production, a preferred scheme of electric pump drainage and gas extraction unit for gas fields with a high gas-liquid ratio is proposed by the mechanical principle and structural design method. Then, the corresponding electric pumps were developed, and the drainage and gas extraction scheme of a permanent magnet electric pump unit with gas-liquid separation in the way of an inverted deflector is designed. Through indoor experiments simulating the downhole gas-liquid ratio environment, the gas-liquid separation ability and adaptability of the design scheme under different good conditions are verified. The results obtained demonstrate that the cable connection process can meet the requirements of high-pressure resistance (≥25 MPa), and the gas-liquid separation effect is very good in vertical wells by adopting the inverted deflector scheme. The separation effect exceeded 90% under different working conditions (production from 30 to 150 m3/day and inhalation gas-liquid ratio from 50% to 95% and even higher) in the experiment with high gas content. The results will promote the gas recovery rate of high gas-liquid ratio gas fields and improve extraction efficiency.
Rock Plate Impact Experiment Based on ANSYS Workbench
Authors: Lu Jun , Huang Jinfei , Lou Caiying , Zhao Xinze , Shang Bei , Huang Jian , Chen Min
Published: December 2023

The study of the physical properties of laminate mainly focuses on the static strength and elastic modulus. Its impact resistance has not attracted enough attention. However, the impact resistance of the multi-layer board used in climbing walls is particularly important to protect the safety of climbers. Using the display dynamics solver ANSYS Workbench and referring to the test method in EN 12572-1-2007, a finite element model of the rock slab impact test was established. The maximum stress and strain of each part during impact were solved, and the vulnerability point of the structure was analyzed. By changing the impact height and solving the influence on the rock slab under each test condition, the results show that the maximum stress of the slab changes nonlinearly. The numerical simulation results provide reference data and new development modes for the development of test methods and testing equipment in the next step of improving national standards.
Experimental Study on the Underwater Explosion Bubble Near deformable boundary
Authors: Su Hao-Chen , Wang Jun , Liu Yun-Long , Gao Yong-Qiang
Published: December 2023

Studying near-field underwater explosions is important for the research of submersible and underwater explosive weapons. In this study, we conducted experiments to investigate the coupling of near-field underwater explosion bubbles with titanium alloy plates and steel plates. Our findings show that the boundary of a titanium alloy plate causes the first pulsation period of a bubble to be longer than in the free field, while the boundary of a steel plate causes the first pulsation period of a bubble to be shorter than in the free field. Furthermore, we simulated the process of the explosion and found that changes in the period may be caused by ventilation.
Study on the influences of temperature and impact speed on the bounce behaviors of superhydrophobic surfaces
Authors: Li Bo , Bai Jie , Fan Lei , Li Yue , Yang Liuqing , Xiao Xiaobing , Xiang Huiying , Yuan Yuan
Published: December 2023

The freezing of water droplets greatly harms overhead conductors and other outdoor infrastructures. Superhydrophobic (SHP) surfaces are an effective and practical method of preventing ice. The SHP surfaces rapidly repel the impact water droplets before freezing. Herein, SHP surfaces with a high aspect ratio and narrow gap nanostructures were prepared on aluminum plates by anodic oxidation, and the influences of temperature and impact speed on the bounce behaviors of SHP surfaces were systematically studied. The drop in temperature delays the escape of the liquid drop on the surface and reduces the bouncing height. Notably, the SHP surface still maintains good bounce behavior at -10 °C. The prepared SHP surface can resist droplet impalement with impact velocities below 2.42 mm/s at -5 °C. This study reveals the bounce behavior of droplets on supercooled SHP surfaces, and this provides experimental guidance for the exploration of SHP in ice prevention.
The Effect of Pore Size on the Mechanical Properties of Biaxially Stretched Silver Nanoplates
Authors: Wang Shanshan , Zhang Yanan , Yang Qinyou
Published: December 2023

In this study, we investigate the mechanical properties of silver nanoplates with pores under biaxial stretching using energy, natural strain, and stress as characterization parameters. Furthermore, we analyze the effect of different pore radius ratios on these mechanical properties. Our analysis, using molecular dynamics methods, reveals that shear stress on dislocations leads to the destruction of the silver nanoplates model. We also found that the fracture time of silver nanoplates is affected by the pore radius ratio; models with larger pore radius ratios have smaller shear stresses and are destroyed earlier. Moreover, we observed that dislocation forms at the corners of square silver nanoplates, and as deformation increases, the dislocation gradually approaches the center of the hole. The closer the hole position is to the model boundary, the greater the shear stress will be. Finally, we demonstrate that when the hole is oval, it creates a new asymmetric dislocation line at its tip, which causes differences in mechanical properties.
Comparative Analysis of Hydrodynamic Performance of Small Wave Buoys
Authors: Zheng Shanshan , Yan Xingkui , Lei Zhuo , Zhang Jiming , Gao Saiyu , Kai Chengyu , Song Haihui , Huang Jiuzhang
Published: December 2023

The hydrodynamic performance of the floating body in seawater is very important. The wave buoy is a small buoy that measures wave parameters such as wave height and wave direction, for the non-powered wave buoy, the hydrodynamic performance mainly refers to the seaworthiness of the buoy body. Seakeeping refers to the motion law of the floating body in the wave. For the wave buoy, the seakeeping of the floating body has an important impact on the measurement of wave data. Therefore, the analysis of the hydrodynamic performance of the wave measurement float is an important reference for evaluating the performance of the wave buoy. In this paper, the hydrodynamic performance of cylindrical and spherical wave-finding buoys is compared and analyzed, and the influence of different structural forms on their hydrodynamic performance is analyzed, which provides a reference for optimizing the hydrodynamic performance of wave-measuring buoys.
Three-channel wide-spectrum temperature measurement technique
Authors: Yu Qiansong , Gu Shengyu , Dong Yuan , Jin Guangyong
Published: December 2023

A theoretical and experimental study of a three-channel wide-spectrum temperature measurement technique is reported. The correctness of the application of the Taylor series to the temperature measurement integral equations is verified theoretically, and the effect of spectral emissivity on the approximation of the Taylor series is discussed. In the simulation results, the insensitivity of the optimal expansion wavelength to the spectral emissivity is revealed and applied as an important basis in the temperature solution method. Temperature measurement experiments using the two-color method and three-channel wide spectrum method were carried out. The theoretical correctness of the three-channel wide-spectrum temperature measurement method and the spatial solution ability of the temperature field are verified.
Study on Measurement of Liquid Viscosity Coefficient
Authors: Li Xiaojie , Lv Xuyang , Yao Guangrui , Zhao Yingjie , Gao Fei
Published: December 2023

Based on the traditional falling ball method, the U-tube design is more suitable for measuring transparent or translucent liquids with a large viscosity coefficient. An electromagnetic relay is placed at the upper end of one side of the tube to ensure that the ball falls vertically through the axis of the tube. The other side is sealed with water to prevent the pollution of the liquid to be measured and improve the measurement accuracy. At the same time, it solves the problem of oil leakage in the existing device for a long time, which is convenient for device maintenance and cleaning.
Mixed Discontinuous Galerkin Method for One-dimensional Biharmonic Equations without Penalty Terms
Authors: Yin Jingjing
Published: December 2023

In this paper, we apply a discontinuous Galerkin method without penalty terms for the solution of biharmonic equations in one-dimensional space. It overcomes the trouble of choosing appropriate penalty parameters to ensure the stability of discrete problems when solving biharmonic problems by discontinuous Galerkin methods. We first introduce an auxiliary variable p = uxx
to transform the original problem into a second-order system. The variational formulation without interior penalty is derived, the well-posedness is present, and the optimal convergence rates under the energy norm and L
2 norm are obtained. Finally, several numerical findings demonstrate its accuracy and capability.
Double-Star Isolation of Maximal Outerplanar Graphs ∗
Authors: Cao Jingdong , Zhang Shumin , Ye Chengfu , Jia Tianxia
Published: December 2023

In the graph G = (V, E), V represents the set of vertices and E represents the set of edges. ℱ represents a family of graphs. A subset S ⊆ V is considered an ℱ -isolating set if G[V\NG[S]] does not contain F as a subgraph for all F ∈ ℱ. The ℱ-isolation number of the graph G, denoted by 𝜄(G, ℱ), is defined as the minimum cardinality of an ℱ-isolating set in G. If the family ℱ consists of a single graph H, then the subset S is referred to as an H-isolating set. The H-isolation number of the graph G, denoted by 𝜄
H
(G), is defined as the minimum cardinality of an H-isolating set in G. Maximal outerplanar graphs have been widely applied in different fields of research since 1891, where they hold significant importance. This paper aims to provide a comprehensive analysis of the H-isolation number in maximal outerplanar graphs,

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, where H ≅ S
1,k+1,k+1.
Cyclic inequalities for generalized mixed width-integrals
Authors: Zhang Yuepu , Li Deyi , Zou Du
Published: December 2023

In this paper, we research the cyclic inequalities of generalized width-integral in convex geometry analysis. Based on previous studies, we use Hölder’s inequality and inverse Hölder’s inequality to study further the generalized width-integral inequalities of the convex body in Euclidean space, establish a series of cyclic inequalities, and give the condition of equality sign.
Boundary element analysis for finite-size quasicrystal plates with a hole
Authors: Wang Huiping , Wang Guixia , Chen Decai
Published: December 2023

The quasicrystal thermal barrier coating technology for engines is one effective means to address the energy-saving and emission-reduction issues in fuel-powered vehicles. It is noted that under loads, quasicrystal components with holes will experience stress concentration at hole edges, which can induce cracks and lead to material failure. Therefore, studying the mechanical behavior of quasicrystal defects is of great significance for improving the reliability of components. However, the boundary value problem of finite-sized icosahedral quasicrystal plates with holes is very complex and difficult to solve analytically. In the article, based on the extended Stroh method, a boundary element analysis is conducted for finite-size quasicrystal plates with a hole. Mainly, Green’s function is derived to obtain the fundamental solutions of an infinite-sized quasicrystal specimen with a hole, and linear interpolation functions and the Gauss integral formula are used to discretize integral equations. Finally, the effects of the size of the medium and the coupling elastic constant on the stress around the hole are discussed. The numerical results show that the boundary element method can be used to analyze both the finite-sized problem and the infinite-sized problem.
A New Discriminant Method for the Stability of Fourth-Order Differential Equation
Authors: Zhao Haiqing , Zhou Yuzhao
Published: December 2023

The stability of nonlinear differential equations has been widely studied based on various methods. In this paper, we transform a class of fourth-order differential equations into a perturbation system and study the stability and asymptotic stability of zero solutions. By utilizing Lyapunov’s second method, we give sufficient conditions for zero-solution stability and asymptotic stability and provide the construction method of the zero-solution asymptotically stable Lyapunov function of such fourth-order differential equations. In addition, this paper removes the requirement of negative definite when the general differential equation is zero solution stable and obtains a looser stability condition. This paper provides an alternative approach to the research of stability of differential systems.
Lp Dual Mixed Affine Quermassintegrals
Authors: Zheng Yanping , Li Deyi , Zou Du
Published: December 2023

Drawn-out dual Lp-Brunn-Minkowski inequality, some ordinary and useful characters and the uniqueness in the matter of Lp dual mixed affine quermassintegrals are discussed, and the equivalence of the inequality concerning Lp harmonic combinations, and its dual Lp- Minkowski inequality is proved.
Research on Multi-parameter Interpretation Method of Advanced Exploration of Mine Transient Electromagnetic Method
Authors: Dong Yi , Li Jingrui
Published: December 2023

To enrich the effective interpretation parameters of mine transient electromagnetic method (MTEM) and improve the accuracy of detection results, based on calculating the apparent resistivity and its depth of the whole period at each moment by dichotomy, combined with induced electromotive force, advanced detection fan diagrams of the apparent resistivity and the slope of the two parameters along depth direction are drawn respectively, and the imaging results of different parameters are compared and analyzed. It is found that there is an abnormal area with good roof and floor connectivity on the left side in the front of the roadway, and the four parameters have different degrees of abnormal reflection at this position. The later advanced drilling revealed that the water inflow was 12 m3/h, which verified that the multi-parameter interpretation results of the mine transient electromagnetic method were right. The above multi-parameter interpretation method for advanced exploration of the roadway not only enriches the interpretation way of the geological body but improves the accuracy of judgment of the geological anomaly body in front of the roadway.
The Integral Points on the Elliptic Curve y
2 = 7 qx(x
2 + 128)
Authors: Wan Fei , Zhao Jianhong , Wang Jihe
Published: December 2023

The positive integer points of elliptic curves are very important in the theory of numbers and arithmetic algebra; it has a wide range of applications in cryptography and other fields.

The main purpose of this paper is to apply elementary methods, the properties of congruence and Legendre symbols, to study the elliptic curve y
2 = 7 qx(x
2 + 128)and proved that the elliptic curve has at most three integer points when q = 5(mod8) is an odd prime number.
Study of the Mechanism of Cavitation in Inner-Hole Rotating Cavitators
Authors: Li Dawe , Wen Jiangbo , Ge Ning , Han Guihua , Zhu Yipeng , Wang Chengjun
Published: December 2023

To investigate the mechanism of cavitation, a mathematical model of the cavitation region and an expression for the gas volume fraction in the inner hole of a rotating cavitator are developed. Then, based on the realizable k-ε turbulence model and the Schner & Sauer cavitation model, the flow field is simulated numerically. With the help of pressure and streamlined distribution contours, velocity contours, and gas phase contours, the three stages of the cavitation process are simulated by the cavitation evolution model. Finally, the rate of heat generation is used as the experimental characterization of cavitation, and the cavitation mechanism is confirmed by experiments involving rotation speed and pressure. The results indicate that the cavitation effect can be measured by the generation of cavitation heat and that the influence of the rotation speed on the cavitation effect is more significant than that of the inlet pressure.
Simulation Analysis of Composite Axial Tensile Failure Considering Fiber Strength Dispersion
Authors: Bu Pengfei , Ruan Wenjun
Published: December 2023

The axial strength limit of composites exhibits obvious dispersed characteristics. Based on the finite element simulation, using the Weibull distribution to describe the fiber strength, and considering the random distribution of fibers within the matrix, a representative volume element of composites was established in this article. The axial tensile failure of T300/BSL914C composites was studied and the effects of fiber tensile strength and volume fraction on the axial tensile strength of composites were analyzed. Results show that considering the influence of fiber strength dispersion, the fracture of fiber bundles exhibits a progressive failure during the composite tensile failure process, and before the fiber fracture, the interface is not subjected to stress. Axial tensile strength increases linearly with the increase of fiber tensile strength and volume fraction. The composite axial tensile strength could be improved by selecting high-strength fibers or increasing fiber volume fraction.
Research on Dynamic Characteristics of the Unit Cableway of the Overhead Passenger Device
Authors: Zhao Chi , Jiang Yuqiang , Ma Chi
Published: December 2023

As an important auxiliary equipment for personnel transportation, overhead passenger device is widely used in coal mine production activities, and safety accidents caused by abnormal operating state are also common. As the basis of intelligent monitoring, it is urgent to study its dynamic characteristics. Based on the Euler beam model theory, the unit cableway system of the overhead passenger device is simplified as a vibration system model of the moving concentrated load load-bearing steel wire rope when the suspension chair is moving. The vibration response equation of the unit cableway system in the form of lateral vibration was established based on the D’Alembert principle, as well as the model frequency distribution and the vibration time domain response of the system’s load-bearing steel wire rope during the operation of the suspension chair was obtained. The frequency and time domain changes of the lateral vibration response under variable operating conditions were analyzed. It is found that the main vibration frequency of the overhead passenger device is concentrated in the first two orders and both have the characteristics of a low midpoint near the unit cableway and high at both ends.
Experimental Study on the Influence of Water Barrier Placement Position on Shock Wave Pressure Peak
Authors: Zhang Hong , Li Qi , Zhang Liang , Yang Wei , Zhu Yongchao , Wang Changbo
Published: December 2023

According to the self-built experimental platform, the shock wave experiment with and without a water barrier was carried out, the influence of the existence of a water barrier on the shock wave pressure peak was compared, and the influence of the water placement position on the attenuation effect of the pressure peak was studied. The experimental results show that the existence of a water barrier can completely attenuate the shock wave over-pressure peak, but the formation of aerosol clouds driven by high-speed airflow after the water barrier wave will produce corresponding dynamic pressure peaks. The effect of attenuating the pressure peak will not be achieved near the water barrier, and the pressure peak can be effectively attenuated farther away from the water barrier.
Random Vibration Analysis of an Axially Moving Viscoelastic Beams based on Complex mode and Pseudo Excitation
Authors: Li Yueling
Published: December 2023

Axially Moving Beams can serve as simplified models for many engineering systems, such as aerial cable trams, power conveyor belts, magnetic tapes, textile fibers, aerospace vehicles, etc. They often work in open environments in the wild, with random excitations. In engineering practice, viscoelastic materials are widely used in various engineering fields. This article studies the lateral random response of axially moving viscoelastic beams under various random excitations. Under the random external excitation of concentrated and distributed loading, analytical expressions of the mean function, correlation function, power spectral density, and mean square function of the random response of an axially moving viscoelastic beam are derived. They prove the correctness and simplicity of the Pseudo-excitation method for solving the power spectral density of the random displacement response of axially moving viscoelastic beams.
Frontal A-pillar impact study based on commercial vehicle cabs
Authors: Peng Xuemei , Zhao Liangliang , Liu Fuyun , Sun Yonghou , Zhang Xu
Published: December 2023

To examine whether the passive safety of the cab of a certain commercial vehicle meets the regulatory requirements in a 90° rollover traffic accident, a frontal A-pillar impact simulation test platform is built according to the regulation JT/T1178.1-2018 and the crash simulation is analyzed in LS-DYNA. The driver’s passive safety is comprehensively considered by taking the deformation of the cab structure and the driver’s survival space as the indexes. Aiming at the A-pillar crash test data that does not meet the requirements of the crash regulations, a joint optimization method of welding and strengthening the structure in the inner cavity of the A-pillar and replacing the original material with high-strength steel is proposed. The optimized cab is again subjected to an A-pillar collision simulation test and the optimized results are obtained. The plastic strain of the cab is reduced from the original 0.21 to 0.175 and the minimum living space is increased. The maximum increase in the vertical distance between the driver’s legs and the steering wheel is 52 mm, which improves the passive safety of the cab to a certain extent and provides a reference for enterprises.
General Series Solutions for Stresses around an Arbitrarily Loaded Hole in the Infinite Plate
Authors: Qi Dexuan , Yuan Ye , Jiao Yongshu , Liu Shuo , Shang Peng , Guo Shijie
Published: December 2023

Based on the linear elasticity theory and the Michell-Fourier series technique, a general series solution for stresses around an arbitrarily loaded hole in the infinite plate is presented. An Airy stress function in the form of Michell-Fourier series is chosen. The stresses are expressed by polar coordinates and two sets of stress coefficients. Arbitrarily distributed normal and tangential tractions on the edge of the hole are expanded into Fourier series. Then the loads are expressed by two sets of loading coefficients. The stress boundary is utilized for conditions on the edge of the hole. The stress coefficients are related to the loading coefficients. The general series solution for stresses around an arbitrarily loaded hole in the infinite plate is obtained. The verification solution of stresses around a uniformly pressured hole, and the stresses around a hole loaded by uniform tangential force are presented. The stresses around a circular hole partially loaded by varying traction are also calculated. The results show that the presented analytical solution is in great consistence with that from ANSYS.
Abnormal line loss identification of distributed PV low-voltage distribution area based on data driven
Authors: Ding Jinjin , Xu Bin , Lou Wei , Peng Bo , Ding Jingya
Published: December 2023

The identification of line loss anomalies in low-voltage distribution networks has been a very challenging problem for a long time. The large-scale access of distributed photovoltaics to the distribution network changes the power flow distribution and further increases the difficulty of identifying abnormal line losses in low-voltage distribution areas. In this paper, an identification method for abnormal line loss in distributed photovoltaic access low-voltage distribution area is proposed. Firstly, we analyze the correlation between the line loss rate and other indicators in the area of distributed photovoltaic access. Secondly, according to the gray correlation degree results, the appropriate indicators are selected, and the k-means clustering algorithm is used to cluster these indicators, through the clustering results, we can detect outliers to determine whether there is a line loss anomaly in the area. Finally, by analyzing the time dispersion degree of the cluster where the outlier point is located, the anomaly coefficient of the area is obtained, and the line loss anomaly is judged according to the anomaly coefficient. To verify the effectiveness of this method, we conduct an empirical analysis of typical containing distributed photovoltaics. Experimental results show that this method can effectively identify the line loss abnormalities in the distribution area containing distributed photovoltaics.
An Improved Optimal Tracking Rotor Algorithm of Wind Turbine Based on Dynamic Adjustment of Compensation Coefficient
Authors: Zhang Yumeng , Bu Jing
Published: December 2023

The Optimal Tracking Rotor method, as one of the control methods for MPPT, increases the compensation coefficient to achieve an improvement in average wind energy capture efficiency, but it causes a significant increase in wind turbine load. There are differences in the energy contained between the high-wind-speed areas and the low-wind-speed areas. This paper proposes an improved optimal tracking rotor method by dynamically adjusting the compensation coefficient, to enhance the capture of wind energy in high wind speed areas and slow down the capture of wind energy in low wind speed areas. After research, it was found that the adjustment of the compensation coefficient varies with changes in wind speed and wind wheel acceleration. In response to this problem, the optimal change curve between the compensation coefficient and related parameters was determined. Fuzzy control was used to achieve dynamic adjustment of the compensation coefficient. Finally, the effectiveness of the proposed method was verified based on simulation results in Matlab/Simulink.
Analysis of Minimum Rotational Inertia Requirements for Power System Frequency Stability
Authors: Zhu Zimin , Duan Yu , Wang Xiaoyun , Wu Genzhu , Ma Jian
Published: December 2023

With the advancement of energy transformation and new power systems, large-scale integration of new energy to replace synchronous generators is leading to insufficient inertia in the system, threatening stable frequency operation. Evaluating the minimum inertia requirements of power systems is beneficial for improving the integration capacity of new energy and ensuring secure and stable operation. This paper establishes a mathematical model of frequency dynamics after a fault and advances an approach to assess the minimum rotational inertia requirements. The proposed approach is tested on the modified WSCC-9 bus system to validate its efficacy.
Research on Subway Harmonic Compensation Control Method Based on SSA Optimized Adaline Algorithm
Authors: Wang Zongyan , Mao Zhongya , Guo Qiyi , Han Xinyu
Published: December 2023

To avoid a large number of harmonics generated by the subway train in the process of operation on the power grid security, the theoretical analysis and simulation experiments on the harmonics of the subway traction power supply system are carried out. Aiming at the problem of severe distortion and fluctuation of network side current at the early stage of train startup, a harmonic analysis and compensation control method based on the Sparrow Search Algorithm (SSA) optimized Adaline Algorithm is proposed, which can be employed to carry out real-time adaptive detection and suppression of harmonics generated by the subway traction power supply system. This method can form a closed-loop training loop with the subway system, and the sparrow search algorithm is used to optimize the initial weight value and learning rate hyperparameters of the Adaline model. Simulation results show that the proposed compensating control can reduce harmonics from 15.12% to 2.89% and the current distortion rate by up to 80.8%. Four error evaluation indexes were used to evaluate the errors before and after the optimization. This method is highly adaptive and can be employed to analyze and compensate system harmonics efficiently.
A Fault Diagnosis Approach for Wind Turbine Gearbox Based on Ensemble Learning Model and Dung Beetle Optimization Algorithm
Authors: Wang Chen , Zhang Xiaochen , Luo Tianjian
Published: December 2023

The gearbox is one of the crucial components in wind turbines, and its performance degradation would give rise to out-of-order or even damage. To accurately identify the fault of the gearbox, a novel fault diagnosis approach based on the ensemble model and the dung beetle optimization algorithm is introduced. Firstly, an ensemble learning model with different activation functions is established. Secondly, the dung beetle optimization is applied to select the base models for improving the performance and generalization ability of the ensemble model. Finally, the proposed method is tested with a gearbox dataset. The experimental results show that the proposed approach achieves higher diagnostic accuracy on the gearbox dataset.
Ultra-short-term forecasting of agricultural intelligent greenhouse power load based on ISDS and MDUS-LSTM
Authors: Yu Binbin , Xin Xiaoming , Kong Weizheng , Wu Hengtian , Wu Xiaoyu , Sun Bo
Published: December 2023

The agricultural smart greenhouse electric load differs significantly from the traditional building electric load. It is more susceptible to the influence of meteorological conditions, featuring poor regularity and significant random fluctuations, so load forecasting faces new challenges. To address this challenge, this paper focuses on a variety of meteorological and historical similar feature extraction, innovates model updating strategies, and proposes a new ultra-short-term forecasting method for agricultural smart greenhouse electric loads. Firstly, an improved similar day selection (ISDS) method is designed. This method considers both trend similarity and magnitude similarity of time series. It sets weights according to the degree of influence of different meteorological features on load, thus improving the learning efficiency of the model. Next, a model dynamic update strategy (MDUS) is designed. This strategy consists of initial training of forecasting model parameters based on historical similar daily loads and online updating of forecasting model parameters based on adjacent daily load data. Then, the forecasting model is trained online and fine-tuned with the parameters based on the adjacent daily load data. The dynamically updated forecasting model is used to achieve ultra-short-term forecasting of the electric load to improve the forecasting accuracy and adaptability of the model. Finally, the effectiveness of the proposed method is verified by actual electrical load data, real-time meteorological data, and NWP data collected in an agricultural smart greenhouse in Shouguang, China.
An optimal allocation model for distributed energy storage in the distribution network based on probabilistic power flow
Authors: Zhao Zhiyu , Ma Zhihao , Liang Weichen , Wang Yajuan , Liu Bo , Tian Qi
Published: December 2023

An increasing number of renewable energy resources (RES) are connected to the distribution network, including wind power and photovoltaic. The volatility and randomness of its power output have brought some problems, including that the voltage exceeds the upper limit when its output is large, and the local power consumption is small. The use of distributed energy storage in the distribution network can effectively alleviate those problems. This paper proposes a method of distributed energy storage capacity allocation for the distribution network, based on probabilistic power flow (PPF). This capacity allocation based on PPF can more accurately describe the impact of the randomness of RES power output. Its validity and correctness are verified based on the improved RBTS-bus 6 model.
Research on optimal dispatch of microgrid with dispatchable load
Authors: Li Runing , Liang Caihao , Jia Yudong , Zhu Yongqiang , Xia Ruihua
Published: December 2023

With the rapid development of society, traditional energy has become increasingly scarce and the problem of environmental pollution has intensified. By analyzing the objective functions of gas turbine, battery, photovoltaic power generation, and wind power generation, their constraints are established, and a microgrid optimal dispatching system is established. Using the idea of particle swarm optimization algorithm, an optimal dispatching model of microgrid with schedulable load is proposed. The particle swarm optimization algorithm runs in the optimal strategy algorithm of MATLAB to predict the optimal dispatching transmission time of the dispatchable load, and finally, minimize the total operating cost of the microgrid system by comparing the output before and after distributed generation in the system and the total load of the system.
Flexible Resource Space-time Layered Optimization Scheduling Considering the Partition Characteristics of Active Distribution Networks
Authors: Luo Busheng , Lin Zhichao , Guo Deru , Cai Weijun , Zhang Zuogang , Zhou Haohan
Published: December 2023

Due to the layout differences between different areas of the distribution network, the electrical characteristics of each partition differ significantly. A flexible resource scheduling model considering distribution network functional zoning is proposed to address this issue. Firstly, electric vehicle charging congestion and willingness indices were proposed in different areas to guide electric vehicle charging, and corresponding controllable load models were established. A cross-regional charging model is proposed to guide users in charging, addressing the imbalance in the number and price of charging stations in each area. Then, a hierarchical scheduling model was developed based on the idea that renewable energy should be fully consumed in the upper layer to minimize the peak-to-valley disparity for the overall scheduling of flexible resources. They were scheduling controllable loads in each area in the lower layer and optimizing the charging positions of vehicles in each area. Finally, taking the IEEE33 node system as an example for simulation, the optimization effect of electric vehicles and controllable loads on the operation of the distribution network was analyzed. The results showed that the proposed method could leverage the resource characteristics of each partition, verifying the effectiveness of the proposed method.
Pilot Protection of AC System in AC-DC Interconnected Grid Based on Traveling Wave Refraction and Reflection
Authors: Gao Shuping , Duan Yunqing , Song Guobing
Published: December 2023

To solve the problem that the voltage travelling wave protection at the AC bus is difficult to detect in the AC/DC interconnection network, a frequency protection principle of the line waveguide using the phenomenon of travelling wave catadioptric is proposed in this paper. According to the catadioptric phenomenon when the discontinuity of traveling wave impedance meets the wave, the fault area is identified by using the different refraction and catadioptric coefficients of faults inside and outside the region. In PSCAD/EMTDC environment, the AC-DC interconnection network model is established, and the protection principle is verified by MATLAB.
Multi-time-scale Optimal Scheduling of Park-specific Integrated Energy System Considering Stackelberg Game
Authors: Huang He , Cao Ximin
Published: December 2023

With the reform of the electricity market, the coupling interaction between different stakeholders becomes increasingly more obvious. This paper proposes a multi-time-scale optimal scheduling model for park-specific integrated energy system operator (IESO) considering the Stackelberg game given the different interest demands of different subjects in the park-specific integrated energy system (IES) and the accuracy of source-load forecasting. Firstly, a day-ahead Stackelberg game model is established with the park-specific IESO as the leader and the park users as followers. Afterward, taking into account the influence of large errors in source-load forecasts, an intraday dispatch model and a real-time correction model based on model predictive control were established. Through the analysis of calculation examples, it is verified that the multi-time scale optimal scheduling of park-specific IESO which considers the Stackelberg game can effectively reduce system operating costs, improve system economy, and stabilize fluctuations caused by source-load forecast errors.
Dynamic modeling of air conditioners based on bat algorithm
Authors: Deng Song , Tan Zhukui , Liu Bin , Zhang Junwei , Tang Saiqiu
Published: December 2023

In recent years, countries have advocated green development and gradually implemented new energy-based power grids. Due to the contradiction between the randomness of new energy generation and the growing demand for residential electricity consumption, the stable operation of power grids is facing a great challenge. Air-conditioning loads make up a large and increasing portion of residential electricity consumption, so monitoring it and establishing a corresponding model to guide residents to use electricity reasonably and ensure that the power grid operates stably is important. Many air conditioning model parameters are based on typical values or use offline identification and need higher accuracy. The paper presents a dynamic modeling approach for air conditioners based on the bat algorithm to realize a comprehensive view of the air conditioners and the buildings to which they belong. A model of the air conditioner and the building to which it belongs is created. Then the bat algorithm recognizes the model parameters and makes iterative corrections. The actual usage scenario is simulated in the form of simulation to generate air conditioner power consumption data and verify its recognition effect. The model is shown to identify the corresponding parameters accurately. It realizes the accurate monitoring of air conditioners in real application scenarios, which is important for comprehensively understanding air conditions.