bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on Distributed Optical Fiber Pipeline Micro Leakage Detection Technology Based on Recursive Least Square
Authors: Yi Kang , Cai Changxin , Liao Ruiquan
Published: October 2022

A very weak vibration signal is generated when the pipeline leaks slightly. However, the commonly used pipeline leakage detection technology cannot obtain this kind of signal normally, thus causing large positioning error. Aiming at the above problems, a pipeline micro leakage detection technology based on Recursive Least Squares distributed optical fiber is proposed. The technology utilizes a dual Mach-Zehnder interference system with high sensitivity and simple optical path structure to monitor the interference signal caused by pipeline micro leakage at all times. Then, the adaptive filter based on Recursive Least Square method is used to denoise the interference signal. On this basis, the cross-correlation algorithm is used to obtain the delay estimation of the two test signals. This article clarifies the positioning principle of the detection technology and conducts the positioning experiment of pipeline micro leakage. The experimental results show that this technology can effectively detect the weak vibration signal generated by pipeline micro leakage and greatly improve the positioning accuracy of micro leakage points. The relative error can be controlled within 1%.
Discussion on the anti external force damage technology of power cable
Authors: Zhang Zhenhai , Niu Lin , Li Hongbo , Wang Lei , He Xiaoyu
Published: October 2022

With the accelerating process of urbanization and the increasing social power consumption, power cable, as an important part of the power system, has the advantages of high power supply reliability, large transmission capacity, less land occupation and less vulnerable to the influence of the external environment. However, urbanization construction is accompanied by a large number of municipal construction, which causes great external breaking pressure on the reliable power supply of power cables. Therefore, the effective anti external breaking monitoring and early warning of power cables can reduce the losses caused by cable external breaking. This paper mainly introduces the cable anti breaking monitoring system, which captures the vibration signal to identify the signal source, such as piezoelectric sensor, sound sensor and optical fiber sensor. This paper focuses on the working principle of three distributed optical fiber anti burst systems based on OTDR (optical time domain reflection), Mach-Zender interference and Michelson interference, summarizes the characteristics and application scope of each method, analyzes the existing problems of power cable anti burst monitoring and early warning technology at the present stage, and gives the summary and prospect.
Research on Segmented Power Supply Technology of Microgravity Experiment facility with Electromagnetic Launch
Authors: Zhang Jianquan , Zhang Yongkang , Guo Ruicheng , Cai Zhiwei , Li Xuzhi
Published: October 2022

The microgravity experiment facility with electromagnetic launch is driven and braked by a linear motor to vertically eject and recover the experimental cabin, forming a microgravity environment in the experimental cabin without external force. In order to improve efficiency and reduce power capacity, the linear motor needs segmented power supply. When the stator of linear motor is powered by sections, there are inevitable longitudinal end effect and transverse end effect, which will bring the thrust fluctuation of the motor and then affect the microgravity level of the facility. The off time of the section switch, the current and back electromotive force during off will affect the thrust fluctuation characteristics of the motor, and then affect the motion characteristics of the facility and the microgravity level. This paper focuses on the segmented power supply control method of linear motor. With real-time current acquisition, low delay power switch, current shutdown at zero crossing and other technologies, a more stable motor drive power supply is realized, the motor thrust fluctuation is reduced, the movement of the experiment cabin of the facility is more stable, and the microgravity level of the facility is improved.
On-line damage assessment of wind turbine blade full-size structural fatigue testing
Authors: Liao Gaohua , Liao Shuwu , Hong Zhimin , Zhang Zhiyi
Published: October 2022

In order to achieve the target damage under the number of design load cycles, an on-line damage assessment system for fatigue loading test is designed based on the interconnection mode of distributed network bus. The system uses the dynamic signal acquisition instrument to collect the blade strain data, improves the Butterworth filter for filtering and smoothing, extracts the peak and valley values of blade load by the local maximum method, establishes the relationship between section load, cycle times and material Goodman curve, and calculates the maximum action coefficient of fatigue damage based on Markov frequency matrix method and fatigue cumulative damage theory. The fatigue damage evaluation system established for the fatigue test of a 56.5m blade is experimentally studied. The test results show that the fatigue loading damage assessment system can realize data testing and real-time processing, real-time assessment of blade damage degree in fatigue loading, and has the same accuracy as the data post-processing method.
Analysis and Treatment of Abnormal Defects in Transformer Oil Chromatography
Authors: Li Rui , Zhang Lei , Chen LiangYuan , Li DaJian
Published: October 2022

This article analyzes the cause of an abnormal defect in the oil chromatogram of a transformer, and puts forward control measures and suggestions. It is analyzed that the cause of the abnormal oil chromatogram of phase A and B of the main transformer is the poor contact o f the dynamic and static contacts of the unloaded tap changer, high temperature and overheatin g, and the development of contact ablation, resulting in abnormal oil chromatogram. The cause of the ablation of the dynamic and static contacts of the no-load tap-changer may be due to the installation and transportation (or electrodynamic shock or U-switch design and other factors), the contacts are not in close contact, the larger contact resistan ce causes the contacts to overheat, and high temperature conditions Sulfur corrosion occurs on the surface of the lower contact, and the corrosion product gradually deposits on the surface of the contact, which further aggravates the poor contact. Although passivation agent is added in t he later period, the protection effect of the passivation agent at high temperature is limited, and it can no longer protect the contact. Under the action of current, the dynamic and static contacts that cause poor contact are gradually ablated.
Research of Property and Calibrate Method for Pressure Release Device of Power Transformer in the Grid
Authors: Jia Wenbo , Zhang Jian , Zhang Hang , Gong MingChen , Sheng Jie , Xing Wei , Dong Deyang , Qu Limin , Song Baiyue
Published: October 2022

This paper introduces the types, internal structures and working principles of common non-electricity protection devices, and theoretically analyzes the cooperation between non-electricity protection devices. For pressure relief devices, the requirements of relevant standards for pressure relief valves are introduced, matters needing attention in field use of pressure relief valves are summarized, and factors affecting the performance of pressure relief valves are analyzed. Finally, using the calibration platform, through a large number of experiments, the influence of external environment temperature, caliber and pressure release times on pressure release performance parameters was studied. The results show that the average opening pressure at high temperature (95°C) is significantly lower than the average opening pressure of 10 times at normal temperature. At the same time, with the increase of ambient temperature, the aging opening pressure and the average opening pressure will obviously decrease, while the average closing pressure will increase. In addition, under normal temperature environment, the test values of aging opening pressure, average opening pressure and average closing pressure have little change. For pressure relief valves with different calibers, under the same rated opening pressure, the calibers of the pressure relief valves are different, which has little influence on the actual opening pressure. Through the research on the operation reliability of qualified pressure relief valves, it is found that the opening pressure after 50 operations and the first measured opening pressure and closing pressure data after 500 operations are relatively stable.
Research on sensing node location technology based on AOA and fingerprint recognition
Authors: Zhang Huanqiang , Yu Lei , Shu Jian , Zhang Han , Liu Yinliang , Cao Yanzhao , Xu Quan , Lin Xinhao
Published: October 2022

In order to meet the needs of intelligent operation and maintenance of distribution networks, a large number of wireless sensors are deployed inside and outside the power grid for digital sensing and immediate control of the grid. However, once these wireless sensors fail, they will generate erroneous data, which affects the assessment of grid security and brings great hindrance to the automation of power system operation and maintenance. Therefore, we propose an AOA and fingerprint recognition-based sensing node location method to achieve accurate positioning of wireless sensing nodes to facilitate rapid troubleshooting. The method first enhances and denoises the signal characteristics of wireless sensing nodes to achieve pre-processing of wireless sensing fingerprint information and solve the problem of fingerprint feature recognition of data samples. After that we combine the node fingerprint information through deep learning models to achieve device type recognition of wireless sensing nodes. Finally, we design the AOA node localisation method, which uses the AOA coordinate system measurement model to perform distance measurement and coordinate conversion on the fingerprint features of wireless sensing nodes to achieve accurate and fast localisation of wireless sensing devices. The experiments prove that the method has a high accuracy rate in the identification and location of wireless sensing node devices, which can effectively improve the efficiency of grid automation operation and accurate troubleshooting.
Virtual inertia control based on fast frequency response
Authors: Qian Huimin , Sun Sunan , Xu Chenglong
Published: October 2022

In order to improve the inertia support of wind power system in case of load disturbance events, a control frequency response method based on Hammerstein-Neural Network (HNNFC) is proposed in this paper. First, the sliding mode control (SMC) law is designed according to the system frequency dynamic response equation. Then, the system is identified based -Hammerstein-Neural Network (HNN). Moreover, the system disturbance is designed of the ESO which is used as the compensator of the Hammerstein model to improve the fast and stable recovery performance of the system. Finally, the simulation results show that this method can not only release the active power through the rotor kinetic energy, but also improve the system stability recovery ability. The simulation can be seen that the proposed method can well reproduce the original control method. Compared with traditional control methods, the proposed method can improve the robustness ability of the wind power system.
Reliability Evaluation Model of Distribution Network Based on Circuit Structure
Authors: Li Minghan , Fu Chenglong , Huang Jingyi , Liu Jiaxin
Published: October 2022

In order to meet the electricity requirements and improve the quality of distribution networks, it is essential to improve the reliability level of the power system. This paper established several mathematical models based on circuit analysis and computer simulation to realize the evaluation of distribution network reliability. Firstly, the Sequential Monte Carlo method was utilized to simulate the indicators of series and parallel circuits, and the Entropy Weight Method was adopted to weight the indicators. Then, simulation results were comprehensively evaluated using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), and the evaluation model of distribution network reliability was obtained. The established mathematical model provided some guidance to construct an industrial distribution network and improve the reliability level of the power system.
Network Security Situation Assessment Based on Attack Graph Techniques
Authors: Yang Jinwei , Yang Yu , Zheng Lu , Cheng Ruixia , Lin Shengnan
Published: October 2022

Network security situation awareness (NSSA) can analyze current network status and predict trends. Intrusion detection systems are used as sources of security factor in situational awareness, and their accuracy affects the assessment of network security. The attack graph can filter out key nodes and enumerate possible attack paths, which has become the main method of risk assessment. Therefore, a network security situation assessment technology based on intrusion detection was proposed. The detection rate of the intrusion detection system was improved firstly, and then the attack graph was combined with the hidden Markov model (HMM) for network security assessment. The experimental results show that this method can effectively speculate the attack intention and reflect the results intuitively and roundly.
Research on Semi-physical Simulation of Direct Drive Fan Based on ADPSS
Authors: Zhang Zhixuan , Yang Dong , Ma Linlin , Zhao Kang , Zhou Ning , Hao Xudong
Published: October 2022

A high proportion of new energy equipment brings problems such as increased power source uncertainty and weaker moment of inertia to the power grid. Through large-scale grid simulation with refined models of new energy equipment, potential grid risks can be discovered and grid security can be effectively improved. The modeling accuracy of the new energy equipment model affects the simulation accuracy of the large power grid. In order to solve the accuracy problem of the new energy equipment model, a semi-physical simulation platform close to the actual equipment is used to carry out simulations of different working conditions. Based on ADPSS, a semi-physical simulation electromagnetic model of a dual-motor dual-power unit two-level direct-drive fan was built, and simulation data of different working conditions were obtained. The direct frequency control method is adopted to optimize the motor model, which reduces the steady-state fluctuation of the semi-physical simulation and improves the simulation accuracy.
Unsupervised classification model of residential power users based on typical load patterns
Authors: Tian Yingjie , Zhai Zixue , Li Fan , Wu Yi , Zhao Yingying , Su Yun
Published: October 2022

It is critical for the smart grid to mining the power users’ consumption behaviors. The accumulation of power data provides the possibility of conducting experiments for research focus on behavior analysis. This paper proposes a residential power users’ classification method based on typical load patterns called UCM-LP, to classify users’ power consumption behavior. The method firstly performs fuzzy grouping on the typical power consumption characteristics of multiple users through two-stage clustering, then divides cluster label to obtain the final power consumption categories of the user. Finally, this paper verified the algorithm using the real household power consumption data, obtaining the specific power consumption category patterns and discussed the differences among power consumption categories.
Design of High-isolation Miniaturized Multi-channel Ku-band Driving Module
Authors: Li Jiangjiang , Bai Fengjuan
Published: October 2022

The driving module is the key component of the electronic scanning array radar system, which controls the radio frequency signal of the whole radar. It must have the characteristics of high performance, low cost, lightweight, miniaturization and easy to use. To meet this requirement, a miniaturized multi-channel Ku-band driving module design scheme is proposed in this paper. The module integrates four-channel T/R amplifier circuits, two-channel calibration switch circuits, and a RF power division network, with a total of 19 radio frequency interfaces, which can significantly reduce the number of active amplifiers in the radar system. The module adopts a positive and negative double-sided open-cavity design, combines with vertical interconnection technology to achieve more than 80dBc channel isolation of calibration switch circuit, and has good gain flatness and inter-channel phase consistency. The overall size of the module is 107mm*84mm*12mm, the weight is only 202g, the transmit power of the odd channel is greater than 26.7dBm, and the transmit power of the even channel is greater than 28.4dBm. This module can be widely used in car navigation, radar detection, and other fields due to its characteristics of small size, rich function, and easy integration.
Research on AT traction network relay protection model based on Feeding Section
Authors: Tan Zihang , Xu Chaozheng , Yin Zijian , Tian Xingjun , Lu Shijiao
Published: October 2022

Relay protection for AT traction networks is the key to maintaining safe and reliable operation of high-speed railways. Existing relay protection in the electrical supply network of high-speed railways often ensures its reliability at the expense of its selectivity. The current reliability-first relay protection scheme no longer meets the current safety requirements for high-speed railway operations, so the need to select a more optimised relay protection scheme is crucial. The fully parallel AT power supply method used in high-speed railways has the Feeding Section as the basic unit. Optimising the relay protection mode of the Feeding Section is of great help in optimising the AT traction network relay protection system. In this paper, the IED model for the protection of the entire Feeding Section is established by building a model based on the relevant rules of the IEC 61850 communication protocol and configuring the parameters of each logical node, starting from the actual project of the high-speed railway. The OPNET software was used to carry out simulations to prove that the IED model for line protection based on the supply arm can effectively balance the reliability and selectivity of relay protection.
To Predict the Power Generation based on Machine Learning Method
Authors: Fan Libo , Wang Yi , Fang Xiang , Jiang Jian
Published: October 2022

New energy including wind and solar energy has developed rapidly in the past years to lower carbon emission. Due to the high uncertainty of power generation of new energy, one challenging task is to predict the power generation so that the grid system can effectively schedule it. This paper focuses on predicting the power generation according to weather forecast. Specifically, we treat this task as a machine learning task which aims at learning a functional model that maps the weather forecast to power generation. We choose XGBoost and LightGBM as the backbone models and propose substantial techniques such as smoothing to boost the model performance. Extensive experiments validate XGBoost and LightGBM are quite suitable for this task and our proposed training techniques can indeed improve the performance.
Multi robot cooperative rescue based on two-stage task allocation algorithm
Authors: Huang Jie , Song Quanjun , Xu Zhannan
Published: October 2022

Task allocation is an important issue in the decision-making of multi robot fire rescue in underground garage. In this paper, a multi robot and multi-objective optimization model is constructed. According to the real-time requirements of fire rescue in the underground garage scene, a two-stage multi robot task allocation algorithm based on ant colony and contract net protocol is proposed, which solves the global deficiency of the allocation result based on contract net protocol and the defect that ant colony optimization can not respond to environmental changes in real time. The comparative test results in dynamic environment show that the two-stage task allocation algorithm is similar to ant colony optimization in global cost, and its real-time performance is better than ant colony optimization.
Virtual Inertia Control of Wind Turbine Based on Model Predictive Control
Authors: Xu Chenglong , Cheng Liang , Qian Huimin
Published: October 2022

A useful method for system frequency adjustment of wind turbines is theoretical inertia control. The classic PD theoretical inertia control has difficulty in parameter setting, and does not provide useful inertial support for the system on a case-by-case basis. Therefore, a theoretical inertia control way for wind turbines on account of Model Predictive Control (MPC) is proposed, which provides inertia support when frequency events occur. To confirm the availability of the proposed control method, MATLAB/Simulink® software was employed for system modeling and simulation. The simulation consequences demonstrate that when the system is disturbed by the load, the proposed MPC theoretical inertia control has better robustness and frequency stability than PD theoretical inertia control.
Dynamic characteristics analysis of magnetorheological semi-active vibration isolator with high-static-low-dynamic stiffness
Authors: Meng Qingyi , Chen Xiaoqian , Zhang Huang
Published: October 2022

High static and low dynamic stiffness vibration isolators have the advantages of high load-bearing capacity and small static displacement, but their negative stiffness components will cause a jump phenomenon at the resonance frequency. A semi-active vibration isolator with high-static-low-dynamic stiffness based on magnetorheological (MR) damper is proposed. The equivalent dynamic model of the MR semi-active vibration isolator is established, and the main resonance steady solution and stability conditions of the vibration isolation system are obtained using the average method. The influences of the basic excitation amplitude, excitation frequency, coulomb force, viscous damping coefficient, load-bearing mass, nonlinear elastic force coefficient and linear elastic force coefficient on the stability and performance of vibration isolation systems are analyzed. The results will provide a certain theoretical basis for the design of semi-active control strategies.
Experimental study on the effect of stirring conditions on the properties of heavy-duty anti-corrosive coatings
Authors: Xiong Yong , Guo Wei , Xu XuHua , Xiao ShanWen , Chen Hao , Zhou Jin
Published: October 2022

The long-term storage of heavy-duty anti-corrosive coatings will affect their stability and even performance. In order to adopt suitable stirring method to make the heavy-duty anti-corrosive coating recover better after long-time transportation to the site, the influence of different stirring conditions on the coating performance was explored. The coating was homogenized and stirred from the three dimensions of stirring equipment structure, stirring time and stirring speed, and the viscosity and adhesion of the coating were measured. The influence of stirring conditions on coating properties was obtained through experiments, and the results were analyzed.
Numerical Simulation of Density Segregation of Al Alloy During Centrifugal Casting
Authors: Sheng Xue , Qian Xiaoming , Meng Longzhou , Wang Zhaodong
Published: October 2022

The centrifugal casting process of 6082 Al alloy was simulated by ANSYS Fluent software. The effect of rotation speed on the flow field and the degree of density segregation of Mg2Si particles was analysed. The linear velocity of the molten metal increased as the rotational speed increased. The Discrete Phase Model was used to track the movement of the particles. In centrifugal casting, the Mg2Si with low density is segregated toward the inner wall of the casting. As the rotation speed increased, the thickness of the enriched layer decreased, but the mass fraction in enriched layer increased, and the degree of segregation intensified.
Stability analysis of multi-legged wheel robot
Authors: Kong Linghui , Zhao Dong , Wang Jinyang , Zhang Chuansheng , Meng Lingru
Published: October 2022

In order to improve the terrain adaptability of the multi-legged wheel robot, CG Projection Method is used to analyse the longitudinal and lateral static stability of the robot. Firstly, the longitudinal and the lateral static stability model of the robot are established in the paper. Secondly, based on the lateral and longitudinal stability model established above, the appropriate factors, including the length of the connecting arm of the robot, the body mass, the angle of the connecting arm and the distance between the two wheels, are selected for orthogonal test analysis. Finally, it is shown that: (1) the angle of connection arm, the body mass, the length of connection arm, the interaction between body mass and angle of connection arm, and the interaction between length of connection arm and angle of connection arm have significant effects on longitudinal stability; (2) the distance between the two wheels, the angle of the connecting arm, the body mass, the interaction between the body mass and the angle of the connecting arms, the interaction between the angle of the connecting arms and the distance between the two wheels, and the interaction between the body mass and the distance between the two wheels have significant effects on the lateral stability of the robot.
Research on energy management strategy of hybrid tractor based on layered decoupling
Authors: Xu Wenxiang , Xu Liyou , Liu Mengnan , Zhang Yonggang , Song Lintao
Published: October 2022

Single energy system can not give full play to its advantages and can not better meet the characteristics of large random load fluctuation in tractor operation. The energy system of hybrid tractor based on hydrogen fuel cell, power cell and supercapacitor in parallel is designed in this paper. For the system, a hierarchical decoupling control energy management strategy based on Haar wavelet and logical threshold rules was designed to realize the hierarchical decoupling of high frequency signal, sub-high frequency signal and steady state signal, and to distribute the power signal after decoupling. The model in loop simulation test was carried out, and the results showed that: Compared with the power following control strategy and fuzzy control strategy, the average efficiency of hydrogen fuel cell by the hierarchical decoupling control strategy established in this paper increases by 2.87% and 1.2% respectively in the experimental cycle. The vehicle equivalent hydrogen consumption decreased by 17.06% and 5.41%, respectively.
Joint state estimation of power battery based on UKPF
Authors: Ma Ke , Xu Liyou , Yang Qingxia , Xu Wenxiang
Published: October 2022

Accurate estimation of power battery state is an important function in battery management system. In order to accurately estimate power battery SOC and SOH and improve the performance of long-term estimation of battery SOC, a joint estimation method of power battery state based on UKPF was proposed in this paper. The particle filter algorithm was added on the basis of the unscented Kalman filter algorithm, and the particle filter algorithm was optimized by the unscented Kalman filter algorithm, which improved the particle degradation problem and improved the accuracy of battery state estimation. Based on the time scale transformation, the battery state estimation was completed, and the SOC and SOH were estimated at short and long time scales, respectively. The SOH estimation results were updated to the model parameters for SOC estimation. The results show that the joint estimation method can accurately estimate battery SOC and SOH with an error of less than 3%.
Shock resistance analysis of a spaceborne electronic equipment
Authors: Li Qibing , Zhang Liangjuan , Liu Jiahua
Published: October 2022

In order to ensure the shock resistance of a spaceborne electronic equipment, this paper carried out finite element analysis and test the response acceleration of the shock test. According to the test data, dynamical response of each part of the system, which is consist of the spaceborne electronic equipment and the fixture, is analyzed. According to the analysis results, the failure risk of a electronic component is identified, and the mechanical design of this electronic equipment has been improved. With a weight increase of 0.4%, the maximum shock response acceleration of the electronic component in the electronic equipment has been reduced by 64%, the shock response acceleration meets the requirements of this electronic component, and eliminates the failure risk of structural and electronic components in the electronic equipment.
Research on the law of dynamic shifting and coordinated section shifting of tractor full-power shift transmission
Authors: Song Lintao , Xu Liyou , Liu Mengnan
Published: October 2022

With the rapid development of China’s agricultural economy, the domestic research on full-power shift transmissions is still immature. In view of the problem of poor transmission shift quality, this paper proposes a tractor full-power shift transmission shifting coordination section law. A transmission dynamics model based on Matlab/Simulink was simulated and analyzed. The results show that the quality of shifting only is better than that of only changing sections, and the quality of shifting after shifting first is worse than that of shifting after shifting first. And selected only the shift and first shift after the two laws of the section, the shortening of the clutch engagement time during the shift only, the impact degree is reduced over time, the first decrease is increased, and the sliding friction work is increased. The change of time between the shift and the transition period, the impact is reduced with time, and the sliding friction work is increased.
Research on Engineering Application of Flue Gas Water Lifting Technology
Authors: Mei Long , Si Paiyou , Wang Zhengming , Wu Xin , Hao Shuai , Xu Jidong , Liu Yubin
Published: October 2022

The application of flue gas water lifting technology in thermal power plants can effectively balance the contradiction between thermal power development and water source protection in water shortage areas. However, at present, the engineering application of flue gas water lifting technology is limited, and the comprehensive research relying on field application is lacking. Based on the actual commissioning and performance test of flue gas water lifting system of a 660MW thermal power unit, the project trial operation and water-saving capacity are systematically studied in this paper. Through the system commissioning test, it is found that the water filling process should be considered in the design of circulating cooling water system in the form of closed water, and the operation safety can be improved by setting expansion tank and adding drainage points. The quantity of delivery water is affected by ambient temperature, circulating water quantity and cooling water temperature. Through the performance test, it is found that flue gas water lifting technology can meet the demand of water replenishment for desulfurization tower and has a positive effect on the suppression of flue gas side dust level.
Strength analysis and optimization of three-bridge rigid frame for mining dump truck using finite element stress linearization method
Authors: Ge Chao , Liu Zhiyuan , Miao Tianfeng , Huo Yantong , Wu Jiemin , Cui Muchun , Han Jing
Published: October 2022

A finite element stress linearization method is introduced into the structural verification of the three-bridge rigid frame, a newly designed frame for the wide-body mining dump truck. This method successfully captures the potential local failure around the structural-discontinuity zone. The results indicate that the suspension supports experience high-level stress under six operating conditions and the most dangerous location of the frame always lies at the weld bead between the suspension support and frame. The stress intensities of the original frame under six operating conditions are all smaller than the allowable value, manifesting that the strength of the original frame can meet the strength requirements. The local modifications greatly reduce the local stress and thus improve the reliability of the frame, manifested by the reduced stress level and stress intensity along dangerous paths. The primary plus secondary stress intensity along the most dangerous path decreases by 16.69% under the condition of free-hanging left front wheel, and by 59.91% under the condition of free-hanging right rear wheel. The present work provides a sound method to evaluate the local failure of the frame for the mining dump truck containing many structural-discontinuity zones, and the result is helpful for the continuous improvement of the frame for the wide-body mining dump truck and provides a guideline for designing a new frame.
A Low-Cost and Lightweight Thermal Management System for Lithium-Ion Battery Modules Based on Composite PCM under Normal EV Operating Conditions
Authors: Ping Li , Yanjun Ma , Zhaoli Wang , Xiaofan Jia , Hongli Ding , Panlong Wang , Jiangtao Gao
Published: October 2022

In this paper, a novel low-cost and lightweight lithium ion batteries thermal design based on EG-based composite phase change material to store heat under normal EV operating conditions is developed and verified theoretically. The three dimensional thermal simulation model is proposed to compute the transient temperature of the battery at some actual driving conditions during discharge. The capability of battery thermal management system based on composite PCM under four kinds of actual electric vehicles thermal safety evaluation condition is investigated, and some factors influencing the system are discussed in detail. Simulation results show that the temperature of the lithium ion battery can be maintained within a reasonable range by adopting the cooling system. The highest temperature of battery discharging at 1C rate can be kept no more than 45.1 °C in the cost of 0.5mm in thickness and 1.02kg in weight increment of PCM and the temperature consistency evaluation methods based on integral values were proposed. The conclusions got in this paper can be valuable reference for battery thermal management design and analysis of dissipating heat against daily driving discharge condition.
Structural Ultimate Strength Analysis of Anti-Collision Facility of Yinzhou lake Bridge Under Vessel-Generated waves
Authors: Wei Zhu , Jing Ge , Changchu Zhao , Wengang Qu
Published: October 2022

Under the condition of complex waters, the long-term action of a vessel-generated wave makes the anti-collision facilities have the risk of structural failure. Taking the Yinzhou lake bridge pier anti-collision structure as the research object, the extreme vessel-generated wave load is calculated, and the structural strength of the floating anti-collision facility under the action of the vessel-generated wave is analyzed using the direct calculation method. The results indicate that the ultimate strength of the overall structure of the anti-collision facilities meets the design requirements, but there is insufficient strength in some parts. A strengthening scheme to meet the design requirements of structural yield strength is proposed.
Adsorption Equilibrium and Adsorption Kinetics of Rare Earth Elements in Coal Rocks
Authors: Bosheng Pan , Zhixiang Zhou , Hengyi Du , Zongzhen Wang , Kai Huang , Yalong Zhang , Shun Liu , Jianbin Liu
Published: October 2022

The adsorption pattern and mechanism of rare earth elements on coal reservoirs are still unclear, leading to difficulties in the application of rare earth elements in monitoring the fracturing effect of coal reservoirs. Through indoor adsorption experiments, the adsorption equilibrium and adsorption kinetics of rare earth elements Nd, Y and La on coal rocks were studied to simulate the adsorption of rare earth elements tracers on coal reservoirs and to explore the adsorption pattern of rare earth elements on coal rocks under different initial concentrations of rare earth elements, different adsorption times and different rare earth element types. The experimental results showed that the Langmuir isotherm equation fitted best, and the adsorption of rare earth elements on coal samples belonged to unimolecular layer adsorption, and the maximum adsorption of rare earth elements Nd, Y and La on coal samples at 25°C were 41.052 mg/kg, 34.301 mg/kg and 95.465 mg/kg, respectively. The proposed secondary kinetic equation can better describe the adsorption process of rare earth elements on coal rocks, indicating that chemisorption is the controlling step of the adsorption rate, with the coal samples showing the fastest adsorption rate for La elements and the slowest adsorption rate for Nd elements. The results of this study provide a reference for the application of rare earth elements in the evaluation of fracturing effects in coal reservoirs.
Research on Automatic Welding Technology of Vertical Fillet Weld
Authors: Jiao Wancai , Wu Jie
Published: October 2022

In this paper, the key automatic welding technology of one-time forming the opposite fillet weld is deeply studied. With the help of the gas electric vertical welding technology and its innovation, it was successfully applied to the test and exploration of the one-time forming technology of automatic welding and equipment of the vertical fillet weld. Major breakthroughs have been made in tackling the key automatic welding technologies of one-time forming vertical fillet welds, filling the gap in this technology in the welding field and accumulating valuable experience for further research and progress of this technology.
Broad Spectrum Detector Based on AlN Crystal
Authors: Fan Zelong , Qin Zuoyan , Sun Zhenhua , Wu Honglei
Published: October 2022

Aluminum nitride(AlN) has an ultra-wide bandgap, which is one of the ideal materials for developing ultraviolet optoelectronic devices and has promising applications in the fields of space environment monitoring and materials science. Due to the existence of defects in the crystal growth process, broad-spectrum detectors were fabricated based on defective state AlN crystals. In this paper, AlN crystal detectors were fabricated and investigated the effect of different electrode work functions on the turn-on voltage. The vertical structure W-AlN-W device achieved broad spectral detection from ultraviolet(UV) to near-infrared(NIR) due to the presence of defects in the crystal, and persistent photoconductivity effect was observed for band-edge excitation. The present work provides implications for the development of AlN crystal-based detectors.
Survey of state estimation based on variational bayesian inference
Authors: Ma Jirong , Ma Qinghua , Yang Shujun , zheng Jianqiang , Wang Shuaiwei
Published: October 2022

State estimation problem in multiple target tracking usually faces high-dimensional uncertainty, including target model uncertainty, data association uncertainty, deep coupling and so on. Variational Bayesian inference provides a way to get the approximation for high-dimensional intractable problem. In this paper, we give the survey of state estimation based on variational Bayesian inference.
S-Transform based time–frequency analysis tool with application to detection of bearing fault
Authors: Cui Zhenghao , Yu Gang , Tian Wei
Published: October 2022

Faults developed in bearings are one of the prime reasons leading to mechanical damage. Recently, the novel technology synchrosqueezing extracting transform was proposed to capture the transient impulses in the non-stationary signal for fault diagnosis. Compared with traditional technology, this method has better anti-interference ability and faster processing speed. However, the method is a method based on short-time Fourier transform (STFT), S-transform (ST) is superior due to its higher time resolution in T-F spectrogram, ability to realize lossless inverse transformation, and property of retaining the original signal phase. Considering the advantages of ST over STFT, we apply this method to the ST in the study, time-reassigned synchrosqueezing extracting S-transform (TSSEST) is proposed and applied to perform analog signal and experimental bearing defect data to verify the effectiveness of the technique developed in a step-by-step manner. The results show that the effectiveness of our method.
Microgrid optimal scheduling based on improved particle swarm optimization algorithm
Authors: Yang Lin , Gao Guige
Published: October 2022

It is of great significance to study how to use intelligent algorithm to optimize the scheduling of microgrid, so as to improve the operation efficiency of microgrid. In this paper, particle swarm optimization(PSO) algorithm is improved by nonlinearly decreasing inertia weight and nonlinearly dynamic adjusting learning factors. Compared with PSO, the global search ability of the improved particle swarm optimization(IPSO) algorithm is improved. IPSO is used to optimize the scheduling of the microgrid grid connection model. The example results show that nonlinearly decreasing inertia weight and nonlinearly dynamic adjusting learning factors can obviously improve PSO. IPSO has faster convergence and lower comprehensive cost of microgrid scheduling. This paper provides an effective method for the day ahead economic scheduling of microgrid.
Fault location method based on Beetle swarm algorithm
Authors: Zhang ShiZheng , Xu Yan
Published: October 2022

With the increasing complexity of the distribution network, the requirements for fault location are becoming higher and higher. In this paper, the Beetle swarm algorithm, which combines the particle swarm optimization algorithm with the Beetle whisker algorithm, is introduced to locate the fault of the multi-source power system with distributed generators through the python simulation ieee33 node example. Compared with the single particle swarm optimization algorithm, the Beetle swarm algorithm has the characteristics of high stability and high fault tolerance.
Power monitoring network security situation awareness system based on Knowledge Map
Authors: Lu Liyu , Liu Muxian , Chen Wendi , Liu Guihua , Yang Yiyue
Published: October 2022

When selecting network security indicators, the conventional security situational awareness system ignores the impact of operation and maintenance index and assets on network security, resulting in a small number of attack events perceived by the system when network nodes are attacked. In order to solve this problem, this research designs a power monitoring network security situational awareness system based on knowledge map. In terms of system hardware, the overall system architecture is composed of data layer, function layer and interface layer, and the data collector is used to collect network security risk data; In terms of system software, the knowledge map graph is used to describe the network security risk data. After calculating the network security vulnerability index, assets, security event compensation and operation and maintenance index, the calculation results are used as the network security index to obtain the network security situation value. The test results show that the system can reflect the attack events in all attack stages, and the number of perceived attack events is significantly more than that of the conventional system, indicating that the system can effectively perceive the security situation of the power monitoring network.
Research review on hydropower-wind power-photovoltaic multi-energy coupling power prediction technology
Authors: Zhang Feng , Zhang Yi , Qiu Yutao , Wu Xiaogang , Tao Yufeng , Ji Qingfeng
Published: October 2022

Energy shortage and environmental pollution have become the world's difficult problems, and the development of clean energy has become an inevitable choice. Solving the high proportion of clean energy consumption will become a major issue in the energy field. Various types of energy sources such as hydropower-wind power-photovoltaic power have coupling characteristics in certain geographical areas, and making good use of these coupling properties can better solve its joint prediction problem. This paper first introduces a brief situation of the development of these fields, proposes the main popular computing methods in this field, and conducts targeted analysis for the mainstream methods such as joint prediction, artificial intelligence and clustering algorithm, and finally puts forward the work value and conclusion of multi-energy coupling prediction.
A smoothing strategy for hybrid storage based on EEMD and two-level fuzzy control
Authors: Deng Hao , Zhang Yingchao , Li Cui , Li Haiming , Liu Peng , Xu JiaFeng
Published: October 2022

Wind power has the characteristics of randomness and intermittence. A smoothing control theory for hybrid Energy storage equipment (HESS) using Ensemble Empirical Mode Decomposition (EEMD) to allot power and two-level fuzzy control theory to adjust the power of the Energy storage equipment is proposed. EEMD can decompose wind power, the battery is used to weaken the long-term power fluctuation, and the super capacitor is used to weaken the short-term power fluctuation. Using HESS can improve the service life of Energy storage equipment.
Capturing wake capture: a 2D numerical investigation into wing–wake interaction aerodynamics
Authors: Li Hao , Nabawy Mostafa R A
Published: October 2022

A wing generating lift leaves behind a region of disturbed air in the form of a wake. For a hovering insect, the wings must return through the wake produced by the previous half-stroke and this can have significant effects on the aerodynamic performance. This paper numerically investigates 2D wings interacting with their own wake at Reynolds numbers of 102 and 103, enabling an improved understanding of the underlying physics of the ‘wake capture’ aerodynamic mechanism of insect flight. We adopt a simple kinematic motion pattern comprised of a translational stroke motion followed by a complete stop to expose wake interaction effects. Representative stroke distance to chord ratios between 1.5 and 6.0 are considered, enabling different leading-edge vortex (LEV) attachment states. We also allow pitching rotation towards the end of stroke, leading to wake intercepting angles of 135°, 90°, and 45°, analogous to delayed, symmetric, and advanced pitching rotations of insect wings. It is shown that both vortex suction and jet flow impingement mechanisms can lead to either positive or negative effects depending on the LEV attachment state, and that stroke distances resulting in a detached/attached LEV lead to beneficial/detrimental wake interaction lift. Pitching rotation at the end of the stroke motion is found to induce a strong rotational trailing-edge vortex (RTEV). For advanced pitching, this RTEV serves to enable either a stronger flow impingement effect leading to positive wake interaction lift if the LEV is detached, or a less favourable vortex suction effect leading to negative wake interaction lift if the LEV is closely attached. The higher Reynolds number led to faster development of the wake vortices, but the primary wake interaction mechanisms remained the same for both Reynolds numbers.
Image Road Surface Classification Based on GLCM Feature Using LGBM Classifier
Authors: Robet  , Juliandy Carles , Andi  , Hendri  , Hendrik Jackri , Tarigan Feriani Astuti
Published: October 2022

The road is a land transportation infrastructure that is often used by the community to support their daily activities. Damaged road conditions will cause inconvenience and especially safety for users. Therefore, road repairs must be carried out immediately. The problem currently being faced by the public works services is that identifying road damage is still done manually, so it takes a long time and costs, therefore the approach can be taken is using a computer to do texture feature extraction on road surface images to obtain information using the GLCM method and classify using the LGBM method for normal, cracked, potholed road surfaces with an accuracy of 90%.