bluuebunny/crossref_metadata_2025 huggingface dataset:
Argon pumpout by ICRF waves in C-Mod L- and I-mode plasmas
Authors: Rice J.E. , Lin Y. , Perks C.J. , Reinke M.L. , Marmar E.S. , Cao N. , Gao C. , Sciortino F. , Wukitch S.J. , Wright J.
Published: May 2022

Pumpout of argon ions by ICRF waves has been observed in C-Mod deuterium L- and I-mode plasmas that had a substantial hydrogen fraction. The effect is manifested by a reduction of core argon x-ray brightness up to a factor of 90% on time scales of tens of milliseconds following injection of ICRF power. For Ar16+, the pumpout is strongest for hydrogen minority concentrations between 0.25 and 0.4, when the ICRF waves are not expected to result in minority heating. Modeling with the TORIC code suggests that the pumpout process occurs when the H/D mode conversion layer overlaps with the 2nd harmonic impurity resonance layer. The magnitude of the argon pumpout is independent of ICRF power above an apparent threshold of ∼500 kW, independent of electron density and appears to decrease as the plasma current is increased. Potential application as a heavy impurity control tool in reactors is discussed.
The hydrodynamic theory of dynamical correlation functions in the XX chain
Authors: Del Vecchio Del Vecchio Giuseppe , Doyon Benjamin
Published: May 2022

By the hydrodynamic linear response theory, dynamical correlation functions decay as power laws along certain velocities, determined by the flux Jacobian. Such correlations are obtained by hydrodynamic projections, and physically, they are due to propagating ‘sound waves’ or generalisation thereof, transporting conserved quantities between the observables. However, some observables do not emit sound waves, such as order parameters associated to symmetry breaking. In these cases correlation functions decay exponentially everywhere, a behaviour not captured by the hydrodynamic linear response theory. Focussing on spin–spin correlation functions in the XX quantum chain, we first review how hydrodynamic linear response works, emphasising that the necessary fluid cell averaging washes out oscillatory effects. We then show how, beyond linear response, Euler hydrodynamics can still predict the exponential decay of correlation functions of order parameters. This is done by accounting for the large-scale fluctuations of domain walls, via the recently developed ballistic fluctuation theory. We use the framework of generalised hydrodynamics, which is particularly simple in this model due to its free fermion description. In particular, this reproduces, by elementary calculations, the exponential decay in the celebrated formulae by Its et al (1993) and by Jie (1998), which were originally obtained by intricate Fredholm determinant analysis; and gives a new formula in a parameter domain where no result was obtained before. We confirm the results by numerical simulations.
Modified Poisson–Boltzmann equations and macroscopic forces in inhomogeneous ionic fluids
Authors: Budkov Yury A , Kolesnikov Andrei L
Published: May 2022

We propose a field-theoretical approach based on the thermodynamic perturbation theory and within it derive a grand thermodynamic potential of the inhomogeneous ionic fluid as a functional of electrostatic potential for an arbitrary reference fluid system. We obtain a modified Poisson–Boltzmann (PB) equation as the Euler–Lagrange equation for the obtained functional. Applying Noether’s theorem to this functional, we derive a general mean-field expression for the stress tensor consistent with the respective modified PB equation. We derive a general expression for the macroscopic force acting on the dielectric or conductive body immersed in an ionic fluid. In particular, we derive a general mean-field expression for the disjoining pressure of an ionic fluid in a slit pore. We apply the developed formalism to describe three ionic fluid models of practical importance: nonpolarizable models (including the well-known PB and Poisson–Fermi equations), polarizable models (ions carry nonzero permanent dipole or static polarizability), and models of ion-dipole mixtures (including the well-known PB–Langevin equation). For these models, we obtain modified PB equations and respective stress tensors, which could be valuable for different applications, where it is necessary to estimate the macroscopic forces acting on the dielectric or conductive bodies (electrodes, colloids, membranes, etc) together with the local electrostatic potential (field) and ionic concentrations.
Classication of all single travelling wave solutions to DSW equations
Authors: Zheng Cheng-Gong
Published: May 2022

In this paper, the traditional DSW conditions was presented. The nonlinear incomplete differential conditions were converted into common differential conditions through travelling wave transformation, and all the definite voyaging wave arrangements for the traditional DSW conditions can characterized by use a complete separation framework for polynomials. The specific voyaging wave arrangements existed as periodic solutions of geometrical functions and sane numbers, lone wave arrangements, doubly occasional arrangements of elliptic functions.
A multi-level representation learning method for the classification with emerging new classes on power event monitoring data
Authors: Pan Xiaohui , Liu Yi , Meng Fan , Xiang Shuai , Zhou Hang , Chen Guang
Published: May 2022

For the classification problem of power event monitoring data, manual rules are mainly used to recognize the known classes of events, and new classes of events cannot be extracted by using existing manual rules. But new classes may emerge with the upgrading of power equipment and traditional representation of this time series data is not proper for the task. To solve this issue, we introduce an effective approach that includes three parts: i) embed the raw object of power event in semantic space ii) learn the representation of power event with multi-level. iii) detect new classes, classify old classes, and update models to classify both new classes and old classes. Experiments on real power event monitoring dataset demonstrate that the proposed method outperforms the state-of-the-art methods.
An improved smoothing factor-extended kalman filtering method for accurate online state-of-charge estimation of Lithium-ion battery
Authors: Zhang Yixing , Wang Shunli , Xu Wenhua
Published: May 2022

The state of charge of battery is an important index of battery management system. The Lithium-ion batteries are widely used in various industries, so they are full of uncertainty, which makes them difficult to estimate the state of charge of Lithium-ion batteries. To solve the problem of low accuracy and large variability in real-time estimation of Lithium-ion batteries, taking Lithium-ion batteries as the research object, the Thevenin model is used to simulate the working characteristics. On the basis of the extended Kalman filtering algorithm, through the influence of the covariance matrix and noise, a smoothing factor is introduced to increase the Kalman gain and improve flexibility. Experiments have proved that the smoothing factor-extended Kalman algorithm improves the flexibility of the algorithm, and at the same time reduces the non-linear error caused by the rapid charging and discharging changes of Lithium-ion batteries. In the Hybrid Pulse Power Characterization test, the maximum estimation error is 0.14%, and the average estimation error is 0.1%. It provides a new method for estimating the state of charge of Lithium-ion batteries.
Precise model of LC active power filter and feedback linearization control
Authors: Ou Zuoyuan , Wang Yingpin , Su Chang , Qu Yi , Peng Hongyan , Hao Xuguang
Published: May 2022

The problems of regulating power quality are more prevalent. In general, Active power filter(APF) is one of the best solution. But the influence of load impedance and grid impedance were widely ignored by a great number of papers, supposed the load voltage is constant and modeling in APF singly, which can’t describe the system accurately. Firstly,there are build an accurate model, including LC APF, load and grid impedance. Secondly, applying feedback linearization and proportional resonant differentiation (FL-PRD) control in inner current loop. Then analyze the influence of load and grid impedance. Once more,checked the accuracy of builded accurate model by Simulink and experiment. Eventually, compare mentioned algorithm in the paper with classical proportional resonant (PR) controller. The results show that it is rather important to set up an accurate model and the proposed algorithm gets a perfect capacity.
Model reference adaptive control for the inclined channel stablization loop of missile
Authors: Lu Juanzhi , Liu Lin , Dong Shimeng , Zhang Xiaoming
Published: May 2022

This paper, A model reference adaptive control method based Lyapunov stability theory is proposed, because it is difficult for the control of inclined channel of missile, due to large disturbance and the dramatic change of missile parameter during the flight. The core strategy is that the real system can be adjusted automatically and in real time to be consistent with the reference model as far as possible, when the output of the real system is different from that of the reference model, so that the real system can run in the best state, this control method can well adapt to the changes of control parameters and external environment. The rationality and validity of the method has been verified by mathematical simulation.
New textile material—spider silk fiber
Authors: Wu Xunxin , Chen Lu
Published: May 2022

Environmental protection and sustainable development are two important topics that draw great concern to the world since various synthetic polymer textile materials have caused environmental pollution to the earth, thus, we need to find new and environmentally friendly materials. Spider silk belongs to polymer material that enjoys favorable reproducibility. Besides, its physical and chemical properties are superior to silk fibers, other natural fibers and most synthetic fibers. Its surface is smooth and soft, lustrous and sheen, it also possesses the characteristics of low temperature resistance, strong tenacity, high intensity, high elasticity, high density and fracture resistance which can be applied to body armors, medical sutures, costumes, etc. As a new kind of textile material, spider silk is environmentally friendly which may bring infinite potential.
Construction and research of repairable air material classification model under principal component clustering
Authors: Qiao Li , Xu Changkai , Li Lexi , Li Hao
Published: May 2022

Aiming at the complex management of repairable air materials caused by all kinds of specifications of repairable air material in practice, a repairable air material classification management method based on principal component clustering is proposed. By analyzing the influencing factors of repairable air material support management, the article constructs the classification and evaluation index system, and uses the principal component clustering to reduce the dimension of the data and perform clustering analysis on the data at the same time. And then we establish the classification and evaluation model of repairable air material. The results of the example show that the classification model and algorithm proposed have high accuracy and efficiency, which can provide support for effective classification of repairable air material.
Effect of sputtering on bridge region of thin film nichrome heater
Authors: Xie Ruizhen , Ren Xiaoming , Liu Lan , Liu Wei , Yu Kexin , Xue Yan
Published: May 2022

A thin film microheater is developed for microthruster ignition, micro detonator, etc. The microheater was fabricated onto a Prex bulk substrate using a micro-fabrication technology. Sputtering precession was studied for the effect on the properties of Nichrome film. The results show that the smaller the thickness of the film, the smaller the grain size of the film, the more uniform the grain distribution, and the better the compactness of the film When the sputtering power is the same. When the thickness of the film is the same, the smaller the sputtering power, the smaller the grain size of the deposited film, the more uniform the grain distribution, and the better the compactness of the film.
Microstructure and softening resistance of Cu-Cr-Ag alloy
Authors: Wang Wanyu , Huang Guojie , Zhang Wenjing , Xie Haofeng , Peng Lijun , Yang Zhen , Feng Xue , Mi Xujun
Published: May 2022

In this paper, Cu-0.5Cr and Cu-0.5Cr-0.1Ag alloys were used as experimental materials to test the softening resistance of the alloys. The results show that the addition of Ag can improve the hardness and softening temperature of the Cu-Cr alloy, and has little effect on the conductivity. The softening resistance temperature of Cu-0.5Cr-0.1Ag alloy is 575 °C, which is 25 °C higher than that of Cu-0.5Cr alloy. The softening process of the alloy is accompanied by grain recovery, recrystallization and coarsening. Ag atom improves the recrystallization activation energy of copper alloy and delays the recrystallization and recrystallization grain growth in the softening process. Recrystallization is the main factor leading to the softening of the alloy.
Parameter importance analysis: Random forest approach
Authors: Hweju Zvikomborero , Kopi Fundiswa , Abou-El-Hossein Khaled
Published: May 2022

During surface roughness modelling, it is crucial to determine the parameters with the highest predictive power since these are the outcome drivers. Based on out-of-bag (OOB) mean square error, the following Random Forest techniques have been utilized to determine parameter importance: mean decrease in accuracy and total increase in node purity. Validation of the results has been achieved using the Bayesian linear regression technique. The PMMA machining experiment has been designed by the Central Composite Design (CCD) Face Centered technique. Cutting speed, feed rate and depth of cut are the control parameters, while surface quality is the dependent parameter. The authors established that the random forest regression algorithm yields an OOB mean squared error of 0.113 and that the OOB mean squared error decreases with increasing number of trees for validation dataset. On the other hand, the OOB mean squared error increases with increasing number of trees for training dataset. Both the mean decrease in accuracy and total increase in node purity techniques reveal that the order of decreasing machining parameter importance is as follows: cutting speed, depth of cut and feed rate. Validation of the obtained results yields the same outcome. Hence, feed rate may be omitted from models for faster and simpler surface roughness prediction.
Advances in binary nitride coatings for cemented carbides
Authors: Wang Xinwu , Sun Haobin , Zhang Hua , Li Changye , Zhao Chengliang , Si Shouji , Yao Haibin , Yu Huijun , Chen Chuanzhong
Published: May 2022

With the development of science and technology, cemented carbide tool coatings for machining are updating constantly. Different chemical elements in tool coatings have different performance. This paper introduces the current status of the use of various chemical elements in carbide tool coatings, common chemical elements include metallic elements (transition metal elements, rare-earth elements and aluminium elements) and non-metallic elements (silicon and boron). In addition, this paper presents the current status of research on related basic coatings which includes CrN, TiN, TiCN and CrCN coating, and it looks ahead the develop of tool coating prospect as well.
Research status of laser cladding material system on titanium alloy
Authors: Di Jing , Yao Jiani , Li Meng , Zhou Shuo , Wen Yuxian , Sun Haobin , Zhang Hua , Li Changye , Zhao Chengliang , Si Shouji , Yao Haibin , Yu Huijun , Chen Chuanzhong
Published: May 2022

Laser cladding technology is an advanced surface modification technology. By selecting different parameters and coating materials, the surface hardness and wear resistance of titanium alloys can be effectively improved. The cladding material is a key factor affecting the quality and performance of the cladding layer. Common cladding materials mainly include self-fluxing alloy powder, ceramic powder and rare earth element powder. This paper reviews the current research status of laser cladding material system on titanium alloy, and explains the problems that still need to be solved and puts forward the outlook.
Degradation simulation of Poly (L-lactic acid) (PLLA) vascular stents based on the continuous damage model
Authors: Su Junjie , Cheng Jie , Zhao Gutian , Hu Xue , Tao Jiayu
Published: May 2022

Understanding the evolution law of degradation is the basis of stents application. Therefore, the degradation of Poly (L-lactic acid) (PLLA) vascular stents was simulated by ABAQUS in this paper. Firstly, the mechanical properties of PLLA sheets were obtained by tensile test. It was found that in the process of degradation, the elastic modulus of sheets almost did not change, but their yield strength and elongation decreased obviously. Then, the anisotropic material model and continuous damage degradation model based on hydrolysis and residual stress were established. Simulation results which showed that the damage of ring bends was larger is consistent with the experiments of some scholars. This confirmed that the modeling method can predict the distribution of damage.
Creep-fatigue damage analysis of a large horizontal molten-salt storage tank
Authors: Liu Bingcheng , Qian Caifu , Zeng Xiangsheng , Wu Zhiwei
Published: May 2022

Molten-salt storage tank is the key equipment of solar-thermal storage system. In this paper, creep-fatigue analysis and evaluation were performed on a large horizontal molten-salt storage tank according to ASME Code Case 2843, and influence of the structural form for opening reinforcement was investigated. Results found that increasing the thickness of the tube was not very helpful for the equipment to pass creep-fatigue damage assessment; On the other hand, the integral reinforced structure was effective to meet the requirement of creep-fatigue damage assessment. For the horizontal molten-salt storage tank studied here, the creep damage was dominant compared to the fatigue damage.
Structural stability assessment and damage recovery studies for re-manufacturing aging grinders
Authors: Bhandari Krishna Singh , Jung Dong Won
Published: May 2022

Remanufacture the used product saves money along with maintaining waste material. Trash material are concern and need to reuse. So remanufacturing technologies is important. Big companies are interested in producing product from reusable materials. Remanufactured products are increasing because it has a benefit for environment as an eco-friendly and energy-economical product. One of big reason for that is, because those materials are part of nature. Remanufacturing is defined as a series of processes to re-commercialize end-of-life products and parts as new products. Various remanufacturing markets already exist throughout the world. However, the size and types of remanufacturing markets differ according to as per demand and country. In this paper, grinding machine damage part was studied for restoration technology. likewise grinding the spindle and chrome deposition. The cause of the damage was evaluated by the damage recovery method. Additionally repaired the surface by deposition of hard chromium plating. The scratching of the stones and tables was examined.
Computer modeling approach for multilayer interlocked woven structures
Authors: Patumchat P , Chaikumming W , Sala-ngamand S , Sriprateep K
Published: May 2022

This study aimed to simulate the geometric modeling of the multilayer interlocked woven structures in three dimensions (3D) using computer aided design (CAD). The simulation of yarn was composed of fibers assembled together for presenting the structures. Two and three layers for multilayer interlocked woven structures were simulated with a filament assemble model and compared with yarn path of single line model. The result showed that the new model developed was more realistic than the previous works. The strength of these models is required as an input to many computational methods such as simulation the tensile/bending properties of fabrics structure or composite parts, forecasting the fiber volume fraction of fabrics.
Research on improvement of vacuum pump production system based on value stream analysis
Authors: Zhu Jinghao
Published: May 2022

In this paper, H company vacuum pump V8 products as the research object, combined with lean production theory and value stream diagram analysis method to identify the key waste problems in the production system; and from the production line balance, facility layout optimization, work in process inventory lean and other aspects of the improvement plan; finally, using Flexsim simulation software to verify the feasibility of the scheme. After improvement, the balance rate of vacuum pump V8 product line is increased by 21.96%, the production cycle is shortened by 36.62%, and the value-added ratio is increased by 51.89%. The practical application shows that the use of value stream diagram analysis technology can help to improve the balance rate of production line, shorten the production cycle, and make enterprises achieve lean production.
On-demand 4WD control of electric vehicles based on electric disconnect differential
Authors: Yu Kai , Lu Tongli , Yan Niwei
Published: May 2022

The Electric Disconnect Differential (EDD) is a kind of newly developed mechanism in powertrain proposed to improve the driving range of electric vehicles. The EDD is ingeniously designed to integrate the dog clutch based on the ordinary bevel gear differential. Through the engagement and disengagement process of dog clutch, the torque transmission of electric axle can be decoupled. Therefore, the on-demand 4WD control based on EDD can be realized by controlling the action of the dog clutch. A double-chamfered dog clutch model and a dynamic model of driveline containing EDD are established in this paper. To improve the performance of front-wheel drive vehicles in accelerating and overtaking, an EDD-based on-demand 4WD control strategy of electric vehicles is proposed. Simulation results indicate that the on-demand 4WD control algorithm can achieve clutch engagement within 100ms. More importantly, electric vehicles equipped with EDD on the front and rear drive axles can improve the trafficability and acceleration performance through the on-demand 4WD control strategy.
Research progress on wireless sensor network (WSN) security technology
Authors: Qichen Wang
Published: May 2022

Wireless sensor network (WSN) has been a frontier technology field that integrates a variety of technologies and has a wide range of applications in the military. Network security is of great significance in military warfare. First, this paper outlines the technical advantages of the application of military based on the technical characteristics of WSN. In military applications, WSN has been used in modern military combat while WSN features easy and fast deployment, high concealment, good fault tolerance, high accuracy and other obvious advantages. Moreover, from the perspective of network security, this paper reviews the research progress of network security technology at the network level and data level. The network level includes security protocols, key management, and secure routing technology, and key management includes pre-shared key mode and random key pre-distribution mode. At the data level, error control and fault-tolerant algorithms are mainly included. Automatic retransmission and forward error correction techniques are traditional error control methods, which should be combined with the specific situation of WSN to propose the corresponding fault-tolerant mechanism. Finally, this paper summarizes the practical applications of WSN in the military. From battlefield reconnaissance and target localization monitoring to destruction effect control and anti-terrorism equipment research, network security has been a top priority. Against the background of practical military applications, this paper summarizes the research significance of network security technology.
Experimental study on resonant acoustic damping for cabin noise reduction
Authors: Chunmei Wang , feng Han , Cheng Shen
Published: May 2022

Toward the goal of overcoming the weight-and-space redundancy caused by simple implementations of various noise-reducing structures each with a single function, it is natural one of the effective solutions that combine the forms and performances of different noise-reducing structures subtly. To this end, we ingeniously blend the dynamic absorber and the damping material into one structure, which is denoted as the resonant acoustic damping (RAD). In this letter, we conducted several preliminary experiments on an aircraft cabin model to verify the effectiveness of RAD for vibration suppression and noise reduction on complex engineering structures. The experimental results show that RAD possesses a dual-effect feature, that is, the narrowband vibration absorption like dynamic absorbers and the broadband vibration suppression like damping materials.
Research on seriation design of Dynamic Kill Drilling (DKD) mixer
Authors: Xiaolong Lian , Bin Li , Bo Zhou , Lin Hou , Kunkun Wu
Published: May 2022

Automatic slurry mixing device, one of the core equipment of dynamic kill drilling (DKD) system, is the key to determine whether the drilling fluid system can provide precise density for bottom layer in time and effectively, and also the key equipment to control the operation risk of ultra-deep water drilling in the face of narrow pressure window. Based on the incompressible viscous flow characteristics of non-Newtonian fluid mixed with seawater and combined with the actual drilling fluid field situation of offshore drilling platform, a kind of tubular DKD mixer with dumbbell shaped nozzle as jet element is designed in this paper, which is verified by theoretical calculation and numerical simulation. Finally, “Y type reverse reflux (60°) + 90° cross jet element” was determined as the final structural design scheme. At the same time, the influences of inlet flow rate, length of eddy current section and incident Angle on mixing effect of mixer are studied, and a seriation design scheme of dynamic kill drilling (DKD) mixer is proposed, and a seriation design chart of product is completed.
Accurate Fault Location Technology of Cable Head in Switchgear based on Phase-based CT and Zero-Sequence CT
Authors: Zhang Lihua , Wang Tie , Gu Yadong , Yang Guodong , Wang Chenguang
Published: May 2022

The fault location technology for single-phase grounding fault of line has been mature, but there is little research on cable head in switchgear using this technology. Because the grounding line selection device cannot effectively identify and locate the single-phase grounding fault of the cable head in the switchgear, a cable head fault model is established. The synthetic zero-sequence current signal of three-phase CT and the zero-sequence current signal of zero-sequence CT are decomposed by variational mode decomposition (VMD). The grey correlation degree is then calculated to analyze the similarity of the two signals. Thus, the precise fault location technology of cable head in switchgear based on the measurement of phase CT and zero-sequence CT is proposed, and the correctness and feasibility of the proposed technology are verified by ATP simulation software.
Transformer Fault Diagnosis Method Based on Neural Network and D-S Evidence Theory
Authors: Zhan Zhongqiang , Yang Dingqian , Wang Jian , Hao Jian , Wang Jie , Ge Zhijie
Published: May 2022

The BP neural network is used to calculate the basic fault probability distribution of the dissolved gas in the transformer oil and the core grounding online monitoring data, and the Dempster-Shafer evidence theory is used to fuse the multi-source information of the basic probability of various types of faults to obtain a transformer fault diagnosis model. Transformer samples are used to verify the model, and the support vector machine and convolutional neural network fault diagnosis models are compared, and it is concluded that the proposed method is better in terms of fault diagnosis accuracy and stability.
Robust scheduling of virtual power plant with power-to-gas device
Authors: Tang Zhuofan , Xiang Jiani , Duan Yuwei , Zhang Hongzhi , Wu Yajie , Wang Weidong
Published: May 2022

The uncertainty of renewable energy output is the key factor should be considered in its participation in power market transactions. By combining renewable energy, adjustable load and energy storage devices into virtual power plants to participate in power market transactions, the risk of renewable energy participating in power market alone can be effectively reduced. In addition, as an important means of energy conversion, the power to gas (P2G) device expands the idea for the effective utilization of redundant renewable energy. In this paper, the robust optimization theory is used to analyze the output of renewable energy and the uncertainty of electricity market price. The stochastic model is transformed into a robust model, which reduces the computational burden of virtual power plant participating in the optimal decision-making of power market. The established model is verified by cases, and the influence of P2G device on the decision-making behavior of virtual power plant is analyzed.
Diffraction and spread of the electron beam with transverse emittance ε in standing wave of light
Authors: Zhou Jianhui , Wang Ying , Guo Jie , Yang Cailian , Zhang Xiaoqiang , Xu Peng , Zhou Qinghong , Xu Yanxia , Ying Make , Tsai Cheng-Ying
Published: May 2022

Electron beam propagation in the light standing wave for both high and low intensity has been calculated by Thermal Wave Model (TWM). The electrons are scattered in high light intensity, as described in the Kapitza-Dirac effect. Numerical results show the significance of the transverse beam emittance to the quality of the diffraction pattern. In low light intensity, the electrons cannot be scattered, but we demonstrate that only the phase of the electron beam is shifted. Theoretical results show that the transverse average beam momentum σp
varies while the effective beam σx
size remains. The TWM phase-space distributions of the electron beam are given and show the influence of the transverse emittance ε on the beam spreading in this situation. Our works show the possibility of using lasers to design electron beam phase plates and quantify the transverse coherence of electron beams.
Study on lightning impulse voltage distribution and Transfer Overvoltage of 500kV transformer
Authors: Ren Hongtao , Chen Jianfeng
Published: May 2022

Lightning shock wave acts on transformer, and the electromagnetic field in transformer winding is very complex. Due to the electromagnetic oscillation inside the winding, overvoltage will be produced on the main insulation or longitudinal insulation of the transformer, and the potential gradient at the end of the winding is very large, so that the insulation of the transformer is broken down. Therefore, the impact resistance of insulation should be considered in the insulation design of transformer. The amplitude and distribution of overvoltage in transformer winding will affect the selection of insulation material and insulation structure. At the same time, the analysis of transient overvoltage in transformer winding can also provide a theoretical basis for lightning warning system of power system. In order to understand the distribution of transient overvoltage in transformer winding, this paper analyzes the models of cake winding by computer simulation.
Diagnosis Technology of Substation Abnormal State Based on Cloud Edge Collaboration
Authors: Wang Chen , Wang Xingliang , Chen Xiuqiang , Wang Peng , Li Zhong
Published: May 2022

The substation monitoring system based on cloud edge collaborative computing is an important application field of power Internet of things (IoT) technology, which can effectively improve the data processing capacity of the system. First of all, the problems of computing range, computing power, delay performance, task priority, information transmission and cross are analysed when cloud and edge computing are applied in the abnormal state monitoring of substation. The application functions of the two computing modes in the monitoring system are studied. Secondly, the system of abnormal state detection and the diagnosis process of substation based on cloud edge collaborative computing are designed. Then, the design of abnormal state diagnosis system for a substation in Laver Park of Lianyungang is proposed. Finally, it is verified that the design has the ability to reduce the data transmission and raise the level of fault processing through the abnormal state diagnosis of transformer oil chromatogram in substation.
Coordinated allocation of multi-station fusion substation based on power-gas system
Authors: Ye Fan , Yu Jianbo , Tian Tian , Li Tao , Liu Chao , Tao Anqi , Wang Qianggang
Published: May 2022

In the context of the large-scale construction of ubiquitous power IOT, an optimal planning model is proposed for multi-station fusion substation that takes coordinated electricity-gas allocation into account. First, the existing traditional substation is upgraded and transformed into a multi-station fusion substation. Then the solution method of the nonlinear optimal model is provided. Finally, an electricity-gas interconnection system is used as an example to test the multi-station fusion substation model. The result shows that the proposed model has certain significance in providing more efficient energy and communication services for the substation.
A Smartphone-Based Infrared Thermal Imaging Temperature Sensor for Accurate Temperature Measurement of Pig Groups
Authors: Jiao Fu , Jiao Leizi
Published: May 2022

Uncooled infrared thermography has shown great potential for rapid screening of the body temperature of pigs. However, temperature measurements can produce serious errors due to variations in body surface emissivity caused by skin stains or differences in emissivity between body parts. To address this problem, a rotatable infrared filter is added to the optical path of the smartphone-based uncooled infrared detector in this paper. By adding and removing the filter to obtain infrared radiation in different wavelengths, the altering spectrum temperature measurement equation is constructed to reduce the effect of emissivity differences in the measurement process of temperature. On this basis, we developed a smartphone sensor based on an uncooled infrared thermography temperature measurement system with altering spectrum. The sensor enables fast and accurate measurement of pig temperature in the group, which can provide powerful technical support for the diagnosis of physiological abnormalities and diseases in pigs.
Research on Fault Diagnosis Method of Secondary Equipment in Intelligent Substation
Authors: Kuang Honggang , Yi Pengfei , Luo Yuanbo , Tan Jinlian , Yin Hong , Wei Senzhong , Wang Ruyi
Published: May 2022

With the continuous development of power grid scale, traditional substations are gradually replaced by smart substations. In view of the high safety risks of the current power system secondary equipment maintenance and fault isolation work. A new smart substation network structure method for fault diagnosis of smart substations is proposed for the relay protection measurement circuit, and the fault status of the secondary equipment of the smart substation is analysed. First, the timeliness and reliability of relay protection are considered, and the intelligent substation network structure is established. Then, the polarity fault characteristics are analyzed, and the generalized transformation ratio is used to establish the fault diagnosis model of the secondary equipment in the smart substation. Finally, the effectiveness of the proposed method is verified by PSCAD simulation.
Low voltage series arc fault identification method based on VMD and RVFL neural network
Authors: Lu Shuangqing , Tian Lijun , Wang Zhiqiang , Wu Yong , Zhang Fangheng , Liu Wenyang
Published: May 2022

In low-voltage distribution system, series arc fault is one of the main causes of fire accidents. The series arc current characteristics of load are similar to its normal working current, and the ordinary current protection device cannot detect it effectively. In this paper, an arc recognition method based on variational modal decomposition (VMD) and random vector functional link (RVFL) neural network is proposed. The series arc current data of different loads are collected by the low-voltage series arc experimental platform, and the arc current characteristics are analyzed. Four different intrinsic mode functions (IMF) are obtained by variational modal decomposition, and their fuzzy entropy is calculated respectively to form an eigenvector data set, which is input into RVFL neural network for training and identification. In this paper, approximate entropy (ApEn), sample entropy (SampEn) and fuzzy entropy (FuzzyEn) are extracted as feature vectors for each IMF of VMD, their discrimination for different loads is analyzed, and the recognition accuracy of RVFL neural network compared with SVM and BP neural network algorithm is compared. It is verified that the arc recognition method proposed in this paper has better recognition effect.
Transmission line distance measurement with millimeter wave radar based on improved robust Kalman filter
Authors: Zhang Qing , Ma Lifeng , Ren Jie , Zhang Min , Pan Shuguo
Published: May 2022

In this paper, a millimeter wave radar ranging algorithm based on improved robust Kalman filter is proposed. In order to solve the problems of multi-point return of radar, unstable output and susceptible to environmental influences in the real-time monitoring of transmission line anti-mechanical collision line. Firstly, the effective target distance minimum extraction algorithm based on time domain is used to filter out the outliers. Next, the continuous output data is subjected to robust Kalman filter to realize data smoothing, so as to improve the anti-coarse interference capability of the system. Finally, static and dynamic experiments were conducted to simulate different mobile states of construction vehicles. The experimental results show that accuracy of distance measurement of our algorithm is about ±0.1m, and the ranging error is 2%, which can meet the overall demand for real-time monitoring of transmission line anti-mechanical collision line.
Research and implementation of a highly reliable transient and same source data comparison method based on fault recorder documents
Authors: Ma Huan , Xu Yao , Xu Chanpeng , Zhang Dongxian , Mu Yunlong , Zhang Hao , Han Minchou
Published: May 2022

The existing fault recording analysis system has powerful functions in the analysis of fault characteristic factors such as waveform analysis, vector analysis, and harmonic analysis. However, it uses redundant fault recording data to analyze, compare and locate faults in the power system. Rarely involved, far from reaching the level it should be, and even wasting fault recording data with large amounts of data and rich information content. A highly reliable transient homology data comparison based on recording files is given. Analytical method. Introduced the comparison method of the recording data from the same source, the content involves how to match the channel waveform of fault recorder documents, how to use the zero-crossing algorithm to align, how to find the starting point of the protection action through the mutation amount algorithm, and how to pass the cubic spline The interpolation algorithm obtains valid data, how to compare the valid data, and finally obtain the comparison result, and give advice on operation and maintenance.
Effect of a high-voltage pulsed magnetic field on microstructure, mechanical properties and corrosion behavior of as-cast biodegradable Zn-Al alloy
Authors: Yang Lin , Li Lei , Cao Fanglin , Sun Ke , Cui Jianzhong
Published: May 2022

Zn alloys as the body’s temporary implants, it have recently aroused widespread attention by researchers in recent years. In order to meet the requirement of biomedical application, biodegradable Zn alloys should possess certain mechanical properties. To this end, it is generally required that the grain structure can be uniform and refined. In this work, a high-voltage pulsed magnetic field (PMF) was employed to homogenize and refine the as-cast biodegradable Zn-Al binary alloy. The results showed that a 6 kV PMF changes the coarse columnar Zn dendrites (739±90.9 urn) to fine spherical grains (187±16.1 urn). Accompanying the microstructural change, the compression yield strength, ultimate compression strength, tensile yield strength, ultimate tensile strength and elongation of the alloy are increased by 48.9%, >11.7%, 15.1%, 29.8% and 128%, respectively. Both the electrochemical and immersion tests show that PMF accelerates the corrosion rates of the Zn-Al alloy.
Thrust Prediction Method of Jet Propulsion for Transformer Internal Inspection Robot
Authors: He Zhen , Wang Yabiao , Sun Xianshuai , Zhao Yuming , Li Zhigang
Published: May 2022

Robot technology has been successfully applied to the internal inspection of large power transformers. In order to further improve the level of robot intelligent control and realize robot motion control accuracy of the floating state, this paper analyzes the factors that affect the jet thrust of the robot propulsion system on the developed spherical transformer internal inspection robot platform based on jet propulsion, and builds an experimental platform. Combining experimental data to establish jet thrust equation. On this basis, the working state of the robot power system is further analyzed, the equivalent discharge model of the robot battery is established, the battery state parameters are introduced into the jet thrust equation. Finally, a mathematical model of jet thrust prediction is established that comprehensively considers the robot power system, control system, and environmental parameters. The establishment of this model lays a good theoretical foundation for the establishment of the robot’s precise dynamics model, fine motion control and intelligent control algorithm.
Research on Acceptance of Intelligent Substation Equipment Based on Secondary System Debugging Technology
Authors: Li Wenwei , Wang Xiaoming , Guo Zipei
Published: May 2022

Substation has always been the hub of power grid transmission, supply and distribution. Its construction has become a key link in the process of power grid construction. In the operation of the power grid, the secondary system provides the basic guarantee for the safe operation of the substation. The safety and reliability of the secondary work is of great significance to the power grid. In order to ensure the safe and stable operation of the secondary system, the protection still adopts the way of directly inputting the voltage and current of the primary system from the current and voltage transformer, and directly controlling the circuit breaker outlet through the relay. This paper mainly aims at the acceptance status of secondary equipment in the intelligent substation. Based on the analytic hierarchy process for data acquisition, analysis and research, obtain the operation acceptance status of secondary equipment in smart substation and make fault prediction. In the example test, the final evaluation score of the secondary equipment in the smart substation is 97.54, which verifies the accuracy of the fuzzy comprehensive evaluation method. Establish a scientific, consistent, feasible and standard state index for the power system.
Virtual Simulation Resource Control Platform for Electric Power Training
Authors: Hao Tengfei , Feng Weixia , Su Ruishi
Published: May 2022

Since virtual simulation needs multiple kinds of data as support, the construction of smooth simulation environment requires higher efficiency in data resource management and control. Based on this, a virtual simulation resource management and control platform for electric power training is proposed. On the basis of analyzing the architecture characteristics of virtual simulation engine, the platform structure of operation process simulation and optimization is designed based on three-layer BS mode. The virtual simulation platform is used as the exchange center to establish the data interface. It builds virtual simulation scenarios through mapping, and implements virtual protection tests through GOOSE messages for data management and protection. The control purpose is realized according to the operation process of the equipment and the inherent protection logic. In this paper, a communication module is designed to ensure smooth data transmission between modules. The test results show that the corresponding time of data resource request is mainly concentrated within 20ms, with good efficiency.
Research on the Probabilistic Load Flow Method of Power System Considering Wind Power Integration
Authors: Xie Hui , Yang Zhong
Published: May 2022

Due to the uncertainty of renewable energy and load, probabilistic power flow as an effective method to analyse the probabilistic properties of power systems. In this paper, a linearized ac probabilistic power flow model is established, and Monte Carlo simulation method is used to analyze the probabilistic power flow of the power grid containing wind farms. By connecting wind farm to node 13 of IEEE14-bus system, the voltage accumulative distribution curves of node 4, node 5 and node 13 are obtained. The results show that the random output of wind farm increases the fluctuation of node voltage, and the fluctuation phenomenon of node voltage becomes serious as the distance of the access point of the wind farm approaches. By connecting wind farms at node 4 and node 14, the voltage accumulative distribution curves of access nodes were obtained. Through comparison, it is concluded that the access of wind farm has a small effect on the voltage of PQ nodes close to PV nodes, but has great influence on the voltage of PQ nodes away from PV nodes. By adding wind farms at node 13, the active power cumulative distribution curves of branch 2-5, branch 3-4, branch 5-6 and branch 6-13 were obtained. By comparison, the active power flow of different branches of the system is affected differently after access to the wind farm. The fluctuation of the active power flow of the branch becomes serious with the shortening of the distance from the access point of the wind farm. The simulation analysis can provide more comprehensive and useful information for the planning and operation personnel of power system including wind farm.
Modeling and Stability Analysis of Interconnected System in Weak Grid
Authors: Wen Chunxue , Gu Yifan , Wang Peng
Published: May 2022

Compared with the conventional grid, the interconnection system has the advantages of high power supply flexibility, high equipment utilization, small installed capacity, and more economical operation. However, unlike in the analysis of stability, the dynamic response of the converter of the interconnected system is faster, and to model its internal structure and control, a new model applicable to it is needed. The article firstly models three different control types of inverters, then starts from the IEEE 9-bus interconnected system composed of multiple types of inverters, models the system and analyzes its stability by root trajectory calculation, and obtains the influence of each parameter change on the stability of the system, based on this and optimizes the sensitive parameters of the system by sensitivity analysis, so as to enhance the stability of the system. Finally, the theory is verified by time domain simulation, and the correctness of the model is verified.