bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Concentration on Shear Stress of Nanyang Expansive Soil Slurry
Authors: Ji Xianjun , Liang Ying , Cao Wenhao , Song Peng , Sun Xiaokang
Published: April 2023

The yield stress of mud is the basis for analyzing the flow and desilting of debris flow. Nanyang expansive soil mud was used as experimental materials, and the rheological curves of mud with different solid volume concentrations were obtained by using the stress scanning rheological experiment of Antonpa mcr702 rheometer. For Nanyang expansive soil slurry with different solid volume concentration, the change process of shear stress with shear rate is analyzed. According to the experimental results, the rheological process of Nanyang expansive soil slurry is divided into three stages: stress growth, stress attenuation and stress stability. The slurry concentration has obvious influence on the dynamic and static shear stress of mud.
Effects of Cementitious Material Content and Sand Ratio on Mechanical Properties of the Dry-Mixing Geopolymer Concrete
Authors: Zhu Jiayuan , Liu Yang , Wu Jie
Published: April 2023

The paper investigates the 7-day, 28-day and 56-day compressive & splitting tensile strength of thirty geopolymer concrete specimens using the dry mixing method. The cementitious material content, sand ratio, along with the water binder ratio were chosen as the variables. Influences of the parameters on the mechanical behavior of the dry mixing geopolymer concrete are discussed in the paper.
Vehicle-mounted Dual Liquid Hydrogen Cylinders Parallel Balanced Transport Experimental and Simulation Research
Authors: Guo Jing , Wu Haiming , Bu Yu , Gao Wanli
Published: April 2023

For heavy vehicle liquid hydrogen storage and supply system, the use of double liquid hydrogen cylinders to increase the supply of liquid hydrogen. When two liquid hydrogen cylinders supply liquid hydrogen in parallel, the flow resistance of the gas and liquid channels of the liquid hydrogen cylinders is difficult to achieve complete consistency, which makes the flow of the two liquid hydrogen cylinders in the process of hydrogen supply different, resulting in inconsistent liquid levels in the two liquid hydrogen cylinders. For this reason, a parallel balanced transport technology scheme of two liquid hydrogen cylinders was proposed. Two liquid hydrogen cylinders with identical size were used to supply liquid hydrogen, and a gas-line connecting pipe was used in the gas path of the liquid hydrogen cylinder to achieve the same pressurization pressure of the two liquid hydrogen cylinders. A regulating valve was used to realize the consistent flow of liquid route at the outlet of liquid hydrogen cylinders. Then, the experimental system modified with real liquid hydrogen cylinder was tested with water medium, and the correctness of the simulation results was verified by the test results. Finally, the simulation results show that the proposed method can ensure that the level difference of liquid hydrogen cylinders meets the requirements in the process of parallel supply of liquid hydrogen.
Location and Capacity Determination for Energy Storage System Involved in Compensating Voltage Sag
Authors: Chen Yun , Wang Jiayu , Feng Huan , Zhang Peng , Ni Luan
Published: April 2023

For the energy storage system participating in the grid voltage sag compensation service, a location and capacity determination method based on the joint compensation strategy of distributed energy storage systems and dynamic voltage restorer is proposed. Firstly, a two-layer siting and determining capacity model for distributed energy storage systems is established, with the upper layer aiming to minimize the installation cost of distributed energy storage systems and the voltage crossing cost of sensitive loads, and determine the optimal access point for energy storage system. The lower layer determines the optimal configuration capacity of the energy storage system by targeting the compensation cost of the energy storage system, the dynamic voltage restorer, and the voltage satisfaction of sensitive loads. Then, the arithmetic simulation with IEEE33 bus system shows that the proposed method can select a reasonable access point for energy storage system and reduce the configuration capacity.
Finite Element Analysis of Steel Strands Subjected to Transverse Impact
Authors: Jin HZ , Bu ZY , Qiu SL
Published: April 2023

In order to further understand the impact resistance of steel strand, a steel strand model was established using finite element software, and the damage process of steel strand by falling hammer impact was numerically simulated to analyze the cross-sectional stress change and damage pattern of steel strand during the process. Suitable element types and material properties were selected, and then the effect of different impact velocities on the response of the strand was studied. Finally, the accuracy of the finite element analysis was verified by comparing with the experimental measurement data, which led to a deeper understanding and knowledge of the response characteristics of the steel strand.
Study on Finite Element Simulation Method and Broken Sling Effect of Single Side Suspension Bridge with Curved Decks
Authors: Zhou GW , Qian CZ , Chen CP
Published: April 2023

As a new type of bridge structure system, the single side suspension bridge with curved decks has the characteristics of typical special-shaped bridge structure, and its forces are relatively complex. The slings are usually fragile components, and the breakage of the slings will affect the safety of the whole bridge structure. Based on a single side curved suspension bridge, the static and dynamic nonlinear models of the bridge were established by using ANSYS general finite element software. Based on the analysis of the parameters, the reasonable values of failure time of sling, the damping ratio of the bridge structure, the effect of the broken sling on the residual internal force, the tensile force of the main cable, the bending moment of the main beam and the vertical displacement are discussed. The results show that the effect of sling breakage increases with the decrease of sling failure time and structural damping ratio, and the effect of sling breakage on the internal force of the main cable is small, but it will cause a rapid increase of the internal force of the adjacent slings on the same side and the main beam.
Bond Strength Prediction Model of Ribbed FRP Bars in Concrete
Authors: Dong HL , Li DF , Yang J
Published: April 2023

The bond behavior of Fiber-Reinforced Polymer (FRP) bars is a critical factor in the mechanical performance of FRP rebar reinforced concrete structures, but until now, there has been limited research on the effect of rib forming process and geometrical features of ribbed FRP bars on the bond behavior, and no relevant provisions are incorporated into the current main design codes. In the paper, the spirally-glued FRP bar was taken into consideration, and bond test data were collected to investigate the main test parameters on the bond failure modes and bond strength. Greater emphasis was placed on the effect of rib forming process and geometrical features of such ribbed FRP bars on bond behavior. Results shown the macroscopic failure mode was pullout failure. More specifically, the spirally-glued FRP bar mainly exhibited shearing off of FRP bar ribs, and bond strength increased by increasing concrete strength. Spirally-glued FRP bars shown higher bond strength by increasing concrete cover which contributes to better confinement to FRP bars. Bond strength of spirally-glued FRP bars could be improved by increasing relative rib height hrd and FRP bar rib width ratio Fr. Multivariate nonlinear regression was adopted to propose a suitable formula to estimate bond strength. The calculated results by the proposed equation were in good agreement with the test results with greater accuracy than the current design codes. This is because the effect of rib forming process and geometrical features of FRP ribs on bond strength is accurately accounted in the proposed equation.
Fire Warning Algorithm based on Combining R-S Fusion Layer Images with Convolutional Neural Networks
Authors: Liu C , Zhou Z , Chen X H , Liu M Z
Published: April 2023

In order to overcome the problems of low detection rate and high false alarm rate of fire detection system, a video fire detection algorithm based on R-S weighted model and convolutional neural network is proposed. First, the R-S fusion layer image is obtained by RGB color space and HSI color space; Then, the convolutional neural network is used to construct the fire detection algorithm. During the training process, the extracted R-S fusion layer image is sent to the convolutional neural network for training. During the detection process, the test image is sent to the model for detection. The experimental results show that the method has more effective flame detection effect.
Seismic Analysis of Prefabricated Hollow Piers Connected by Grouting Sleeves
Authors: Ge JP , Xie S , Yan XF , Zhang T , Liu SD
Published: April 2023

Prefabricated piers with hollow sections can save concrete, which is one of the important ways to reduce carbon emissions. In order to study the mechanical performance of prefabricated hollow piers connected by grouting sleeves, three rectangular hollow-section bridge piers with different shear-span ratios were designed, and quasi-static loading tests were carried out to compare the failure modes of prefabricated hollow bridge piers and the influence of the overall mechanical performance. The research results show that: the existence of joints in prefabricated hollow piers will cause a certain pinch effect on its hysteretic curve; The increase of the shear-span ratio will improve the ductility and change the failure mode of the bridge pier, but the ultimate bearing capacity will decrease accordingly, and the overall stiffness of the hollow bridge pier will be significantly reduced. The problems that need to be paid attention to in different design states and the solutions are put forward. The performance of prefabricated hollow piers with grouting sleeves can meet the needs of operation and can be used as an alternative solution for prefabricated assembled viaduct piers.
Shaking Table Test for Seismic Isolation Performance of Adjustable Height Seismic Isolation Rubber Bearing
Authors: Wang H , Lin FJ , Xia ZH , Shi Y
Published: April 2023

To study the seismic isolation effect of adjustable height seismic isolation rubber bearing, a continuous girder bridge was subjected to a shaking table test study with full bridge scaling to compare the seismic isolation effects of plate rubber bearings, natural rubber bearings (LNR) and adjustable height seismic isolation rubber bearings under different types of seismic waves, loading directions and seismic intensities.The test results show that when the seismic intensity is small, the seismic isolation performance of the three types of bearings is relatively close. But when the seismic intensity is large, the seismic isolation effect of the adjustable height isolation bearing is better than that of the plate rubber bearing and LNR bearing. Adjustable height isolation rubber bearing can significantly reduce the acceleration of the bridge deck plate, shear force and bending moment in the bottom of piers.
Seismic Performance of Self-reset Piers Assembled with External Replaceable Energy Dissipation Rings
Authors: Shu J , Zhang YY
Published: April 2023

In order to improve the shear and energy dissipation capacity, this paper proposes a kind of external replaceable energy dissipation ring segment assembly self-reset pier. The ABAQUS platform is used to simulate the refined model of pier and energy dissipation device. Then the influence of different energy dissipation modes on the seismic performance of bridge piers is studied by pseudo-static analysis. Finally, the influence of different parameters of energy dissipation ring on the seismic behavior of bridge piers is analyzed. The results show that the capacity of shear resistance and energy dissipation of the pier with two energy dissipation lines is significantly higher than that of the pier without energy dissipation devices. Reducing the radius of energy dissipation ring can effectively improve the lateral bearing capacity and cumulative energy dissipation of bridge piers. The thickness of energy dissipation ring has little effect on the seismic performance of bridge piers. Increasing a pair of energy dissipation rings can increase the cumulative energy dissipation of bridge piers by 31.1%. Although the residual displacement of pier top increases, the residual displacement angle is still less than 0.5%.
Dynamic Responses of Spread Slab Beam Bridges Considering Inconsistent Road Roughness Conditions
Authors: Wu H , Jiang DQ , Zhang YY , Dai J , Jiang XF
Published: April 2023

In order to deeply study the dynamic response of a new type of low section short span bridge system, the numerical analysis of the extended plate girder bridge under the action of moving vehicles was carried out. In the study, the inconsistent road roughness conditions are considered, and the influence of vehicle speed on the influencing factors is discussed. The analysis results show that under various load conditions, the structural response of the outer plate beam is more critical. In addition, the amplification effect of external plate beam caused by consistent pavement roughness is greater than that caused by inconsistent pavement roughness. The torsional mode of the vehicle can be activated by the input excitation of inconsistent pavement roughness conditions, which should be handled carefully in the design.
Improved Transformer Based Hashing for Cased-based Pneumonia Retrieval
Authors: Liu Wei , Xu Da
Published: April 2023

The deep hash method has been proved to be the most effective nearest neighbor search technique in large-scale image retrieval. However, up to now, deep hashing in medical image retrieval has been dominated by convolution network architecture, such as Resnet. Inspired by Transformer, we integrate Transformer into the deep learning framework. Our framework is mainly composed of two main modules: (1) In order to solve the problem of big difference among different subclasses of medical image categories, the Transformer model is improved in this paper. The external attention is used to replace the self-attention in the original Transformer model, and the feature acquisition ability of the model is improved by capturing the correlation between samples. (2) In addition, in order to learn compact binary coding, we adopt Bayesian framework for end-to-end learning. We conduct experiments on ChestX-ray Pneumonia dataset, and compare the proposed algorithm with the commonly used depth hashing method. Experimental results show that the MAP values under different hash bit codes are better than the existing deep hash methods, which proves the effectiveness of the proposed method.
White Matter Segmentation in Brain MR Images of Premature Infants using Deep Learning Model
Authors: Liu W , Ye F , Wan XT , Zhao WH , Yan R
Published: April 2023

White matter injury is the most common form of brain injury in premature infants, which is highly associated with poor brain development. White matter segmentation in brain MR images is very important for early detection of brain injury in premature infants. In this paper, a deep learning based approach is proposed to segment the white matter region of premature infants. We retrospectively analyzed 63 preterm infants with gestational age < 37 weeks who underwent MRI examination. Firstly, the U-Net deep learning neural network model is used to automatically segment white matter, U-Net++ and ResU-Net are used as controlled experimental groups, and the Dice coefficient and Iou coefficient are used as evaluation indicators for white matter segmentation. In the above experiments, the U-Net network has the best experimental results. Segmenting white matter on the training set with a Dice coefficient of 0.90 and an Iou of 0.82, respectively. The test set was used to validate the performance of the proposed model, with a Dice coefficient of 0.83 and an Iou of 0.71, respectively. Secondly, we performed image binarization step on the segmented white matter, and used Gaussian filtering, flood filling and connected component analysis to process the automatically segmented white matter region, and finally obtain a white matter region with clear boundaries.
A Measuring Tool for Interrupt Latency Based on Linux
Authors: Shi Q , Chen LJ , Qiao Z
Published: April 2023

Linux has been used more and more in the field of industrial control and robot control, the non-real-time nature of the final human-computer interaction program may cause system performance impact in industrial production. Interrupt response time is an important indicator to measure the real-time performance of real-time operating systems. Accurate test data can be used as an evaluation index for selecting the real-time performance of the operating system. In order to improve the real-time performance of Linux, analyze real-time problems, and solve possible real-time bottlenecks, this paper designs a probe-type tool that can measure the interrupt response time, output the interrupt call stack, and analyze the reasons for high interrupts. By optimizing specific limited and high-latency paths, Linux can still maintain an acceptable range of latency for a long time under various high-load scenarios. After testing, the tool has good measurement accuracy, which provides a basis for developing real-time tasks and solving real-time problems.
Networking Scheme for Power Grid System Based on Emergency Communication Vehicle and Unmanned Aerial Vehicle
Authors: Zhou Z , Li Y H , Chen X H , He T T , Liu C , Yuan F , Zeng X H , He W
Published: April 2023

Emergency communication vehicle and UAV are important equipment for power emergency disposal. Emergency communication vehicle (ECV) can quickly reach the disaster area with weak signal, no signal and no power supply. UAV has the advantages of flexible and repeatable post disaster data transmission. Combining the advantages of both, this paper proposes a network architecture based on ECV-UAV scheme. The experimental results show that the scheme can effectively improve the efficiency of power emergency disposal.
Non Intrusive Power Load Monitoring Method Based on Machine Learning
Authors: Guan ZX , Song CH , Huangfu HC
Published: April 2023

In order to improve the accuracy of non-invasive power load monitoring and shorten the monitoring time, a new non-invasive power load monitoring method based on machine learning is proposed. Firstly, the power load data is collected by sensors and normalized. Secondly, based on the normalized results of power load data, the RBF neural network model in machine learning is used for iterative training to extract power load characteristics. Finally, according to the characteristics of power load, the hidden Markov model is used to transform the non-invasive power load monitoring problem into a decoding problem, and the improved Viterbi algorithm is used to solve the hidden Markov model, and the non-invasive power load monitoring is completed according to the obtained state sequence.
A Scheme for Distribution Automation Terminal Design Based on ESIM
Authors: Wang XZ , Li ZT , Gao JZ
Published: April 2023

To realize the operation monitoring and control of distribution network, improve the reliability of power supply and reduce the intensity of operation and maintenance, a design scheme of distribution automation terminal based on eSIM card is proposed. Based on the analysis of eSIM technology and its characteristics, the basic workflow of eSIM card is provided in combination with the remote configuration requirements of power system. Then the main control function and communication module design of the distribution network system are analyzed and explained in detail, with emphasis on the communication interface circuit and software design. The system also integrates AngularJS and SpringBoot to make the platform have the technical characteristics of separation of front and back stations and strong reliability. At the same time, the dial-up and positioning information are integrated into one module to realize real-time monitoring and control of the remote master station. The experimental analysis results show that the scheme has certain advantages in the reliability of distribution automation terminals and the simplification of operation and maintenance management, which increases the integration and functional diversity of power equipment.
Detail extraction of mechanical component image based on depth learning
Authors: Liu Lan , Qin Ping , Wu Xinqiao
Published: April 2023

Aiming at the problem of feature extraction, recognition and classification of machining features of various mechanical part models, an image detail extraction method based on deep learning architecture is proposed. We use the median filtering method to filter the impulse noise in the image initially. After horizontal tilt correction, the contour image is divided into several fan sub regions. Then, the structural parameters of YOLOV3 network are optimized to make it more suitable for small target classification detection of industrial parts on the basis of fully retaining the feature extraction ability of depth convolution network. The simulation results show that for original YOLOv3 algorithm, the improved network model has good robustness, and the problems of different scales, low feature utilization and occlusion in part detection which are obviously improved. Compared with the traditional methods of feature extraction and classification of mechanical part images, the deep learning strategy also shows greater advantages.
Research on Short-Circuit Impedance Analysis Method of Auto-transformer for Side Column Voltage Regulation
Authors: Zhao ZG , Zhang SQ , Cheng HC , Xu ZY , Tan RJ
Published: April 2023

In order to realize the accurate analysis of the impedance of transformers with complex connection relations, this paper derives the impedance calculation method of low-voltage excitation side column linear voltage regulating autotransformer by using the power method. The transformer network with different taps is analyzed, and the calculation formulas of transformer HV-MV impedance, HV-LV impedance and MV-LV impedance are derived. The analysis is simplified to the solution of concentric column coil impedance and magnetic potential of each coil. By comparing the calculated data of actual products with the measured data, the calculation deviation of this method is controlled within 2.03%; By using the finite element method, the impedance of the transformer with the measures to control the magnetic shielding is analyzed and calculated. By comparing the impedance of the transformer with different measures, it can be confirmed that the magnetic leakage measures have an impact on the impedance of the transformer.
Design of Quadrotor Aircraft Control System Using PID Method
Authors: Tian S , Zhang JW
Published: April 2023

In order to realize the precise control of the dynamic performance of the four rotor aircraft, a PID based controller design method for the four rotor aircraft is proposed in this paper. Firstly, the mathematical model of the four rotor aircraft is established; Then, the control algorithm and parameters are simulated based on PID control method, and the control rules and controller parameters are designed. The simulation results verify the effectiveness of this method.
Research on battery charging automatic equalization system based on double closed loop controller
Authors: Li JL , Qu BZ , Liu XJ , Yuan YL , Peng WJ
Published: April 2023

In order to improve the equalization control efficiency of the battery charge equalization system, this paper applies the double closed-loop controller to the battery charge automatic equalization system. First, the overall block diagram of the hardware circuit of the charging system is designed, and the switching control of charging and discharging is completed by using TMS320F2812 chip. Secondly, the optimal charging current is calculated according to Mars law. Then, a double closed-loop controller is introduced to balance the battery charge, and the charge balance equation is constructed and solved. Finally, the adjusted parameters are obtained to realize the automatic charging equalization control. The experimental results show that the equalization control time of this method is always within 25s, which indicates that its charge equalization control effect is good.
Reliability Analysis of Next Generation Power Communication Network Based on SDN
Authors: An GC , Wang XZ , Wang Q
Published: April 2023

To provide basic support of information communication technology for the construction of the next generation power communication network, the reliability service support mechanism of SDN controller in the power communication network deployment scheme is studied in this paper. We analyze the security protection architecture design of power communication network based on SDN, and establish a mathematical model of controller deployment that conforms to the characteristics of power communication. Then, the inter community reliability analysis and backup method is introduced to solve the controller deployment problem in SDN network by optimizing the power of the controller in the community. In the simulation process, the network virtualization and controller are designed in detail. The experimental results show that the SDN controller placement algorithm based on community clustering ensures the reliable operation of the power grid, and it can effectively reduce the service transmission delay and packet loss rate.
Power Big Data Analysis Platform Design Based on Hadoop
Authors: Zhao Liuqi , Wen Xing , Huang Zhenlin , Wang Ning , Zhang Yuheng
Published: April 2023

To better analyze and process power data to obtain effective information, a power big data analysis scheme based on Hadoop architecture is proposed. We analyze the cloud computing environment Hadoop distributed platform to obtain massive data of large-scale distributed power system. According to the characteristics of intelligent power consumption data, common data mining algorithm modules such as parallel classification algorithm and parallel real-time clustering algorithm are designed, and the implementation of clustering algorithm with different principles is further analyzed. Then, HBase is adopted to access data in a distributed way, and MapReduce is used to realize the visual management of power GIS data. The experimental results show that the parallel processing method of power big data based on Hadoop has high efficiency and good scalability, and the algorithm has good identification ability for massive data in the cluster mode.
Power Visualization System Based on IoT and eSIM Card Technology
Authors: Wang Q , Gong S , Fu YF
Published: April 2023

To improve the quality and efficiency of power system management in power transmission and transformation equipment, a visualization system based on IoT and eSIM card technology is designed. The scheme adopts RFID, network development, .NET technology, MSSQL and related technologies and tools to realize the basic functions of the life-cycle management system of power transmission and transformation equipment. At the same time, the On air card writing of eSIM card is used to directly correct the communication parameter settings of the terminal, and the dialing and positioning information are integrated into a module. The visual component uses the latest Web development technology to design and complete the view editor function. Finally, the visual monitoring and data presentation functions of the equipment are tested based on the scenario design, and the results show that the system can achieve real-time monitoring and centralized management under the IoT environment, and comprehensively improves the intelligent level of the power system.
Design of the Integrated Performance Testing Device for Electromagnetic and Static Relays Based on Single Chip Microcomputer
Authors: Lin LP , Qiu YY , Peng YY
Published: April 2023

In order to improve the action performance of the relay, this paper designs an electromagnetic static relay comprehensive performance testing device based on MCU. First of all, a master-slave design structure is proposed, which is composed of a low-power, high-performance Cortex-M3 core high-speed microcontroller. Then, the one-time test model and control logic suitable for testing coil resistance, action/return voltage, coil action power, action/recovery time, contact resistance and working power consumption of AC and DC relays are emphatically introduced. Finally, through experiment testing in substations and power plants, the intelligence, rapidity and integrity of the device are verified.
Comparative Study on Different Temporary Blocking Schemes of Valve Control in VSC-HVDC System
Authors: Ai Liang , Bai Leicheng , Du Ke , Liu Xun , Dai Di , Wang Di , Yu Shanshan
Published: April 2023

To improve the fault ride-through capability of the VSC-HVDC system and ensure the safe operation of the equipment, it is necessary to design the temporary blocking scheme of the converter valve of VSC-HVDC. Taking the Chongqing Hubei Back to Back VSC-HVDC Project as the research object, this paper first analyzes the fault types of the VSC-HVDC system, obtains the fault types of the AC fault ride-through; and then, according to the requirements of system fault ride-through, three-valve controlled temporary blocking schemes are designed: global blocking, phase splitting blocking and bridge arm separated blocking. Finally, based on the RTDS real-time simulation platform, the actual valve control and control protection systems are connected. Comparative simulation tests are carried out to verify the three temporary blocking schemes. The simulation results show that the bridge arm separated blocking can ensure the fault-passing ability of the converter valve and has good electrical characteristics. In practical projects, the bridge arm separated blocking scheme is recommended for valve-controlled bridge arm overcurrent protection.
Research on cloud-edge AC Power Monitoring Systems based on MODBUS
Authors: Mu Xiangcheng , Du Yuyuan , Wang Hui
Published: April 2023

With the development of the Internet of Things and automation technology in the industry, the types of equipment in the industrial field are increasing, and the data parameters of the industrial process are gradually becoming complex. It puts forward higher requirements for the system perception layer’s real-time performance, reliability, and maintainability. The original data acquisition architecture is not easy to ensure the reliable transmission and real-time processing of massive industrial data. In order to solve these problems, this paper designs an AC Power Monitoring System. It proposes a cloud edge computing framework based on MODBUS: First, the data is collected and sent to the edge server by MODBUS through the RS485 bus. Second, combined with the advantages of the powerful service capability of cloud computing resources and the low transmission delay of edge computing, the edge side and cloud side will work together. Finally, the functions of data reading, uploading and sending, correction, configuration, and fault alarm are realized. The field operation shows that using a cloud edge computing framework can reduce the processing pressure of cloud computing, reduce network latency and lower requirements for network bandwidth and make the system efficient and safe for collecting and analyzing big data. The cooperation of MODBUS protocol enhances the reliability and practicability of communication. The cloud edge computing system based on MODBUS is easy to design and maintain and is suitable for many monitoring systems, which have high promotion value.
Research on portable constant pulse current source device
Authors: Li Hongda , Dong Bowen
Published: April 2023

A set of portable constant pulse current sources with STM32 as the control core is developed, which mainly involves the SCM control module, operational amplifier circuit module, pulse output module, power module, key module, and display module. Based on the traditional constant-current source circuit design, the real-time display control system is constructed by software programming optimization, which has the characteristics of portable and strong stability. By connecting the field effect tube and operational amplifier in series to form a feedback loop, the current output accuracy is improved and the stability of the current output is ensured. The experimental results show that after the op-amp circuit is introduced into the series feedback system, the front and rear order circuit can be more stable, and ensure the reference voltage is stable at the same time, through the duty cycle of PWM wave to adjust the current output, so that the constant current source output 0~2mA adjustable low-frequency stable current. At the same time, in terms of human-computer interaction, in addition to the use of buttons to adjust the current at both ends of the load, a small OLED display screen is used to display the current, voltage, and pulse frequency in real time. The experiment shows that the instrument has high stability and load adaptability, and has high practical value.
Improved Design of Feedback Matrix of Adaptive Observer for Induction Motor
Authors: Huang Shanshan , Deng Xin , Xing Pengkun , Su Chongjun
Published: April 2023

In order to address the issue of the induction motor speed sensorless vector control system’s poor dynamic performance at low speed, this research suggests a brand-new feedback matrix algorithm for the full-order adaptive observer. Firstly, the open-loop transfer function based on the back-EMF error is analyzed, the stability conditions of the induction motor operation are deduced, and a preliminary framework is established for designing the feedback gain. Secondly, in order to maximize the system’s dynamic performance, the damping ratio of the speed identification system is chosen as the subject of study. To achieve this, the pole of the second-order characteristic equation of the observer’s complex number system is set up to satisfy the premise of stable operation at low speed and inverted state. The outcomes of the simulations confirm the method’s efficacy.
New Technology of Three-phase Unbalanced Overvoltage Suppression and Voltage Arc Suppression Based on Distribution Network
Authors: Zhou Duyao , Li Shilong , Su Xueneng , Sun Shihang , Liu Xiaohan , Zeng Xiangjun
Published: April 2023

Given that the existing passive arc suppression technology of the distribution network cannot eliminate three-phase unbalanced overvoltage and the difficulties in dynamic measurement and hardware implementation of active current arc suppression equipment based on power electronics, a new technology of unbalanced overvoltage suppression and voltage arc suppression based on flexible control of distribution network zero sequence voltage is proposed. During normal operation, we inject current to eliminate three-phase unbalanced overvoltage; in case of a grounding fault, the system neutral point voltage shall be actively regulated, the fault phase voltage shall be reduced, the arcing conditions shall be destroyed, and the fault arcing shall be fundamentally realized. The 10 kV distribution network model is built in PSCAD/EMTDC simulation environment to verify the new technology of unbalanced overvoltage suppression and voltage arc suppression of zero sequence voltage flexible control. The simulation results show that the new technology can effectively suppress three-phase unbalanced over-voltage, reduce fault phase voltage, and realize reliable arc suppression of grounding faults.
Research on Wide-band Domain Current Sensing for Bushing End Screen Based on TMR
Authors: Hao Yu , Wenzhi Chang , Yanpeng Gong , Shuai Yuan
Published: April 2023

The transformer bushing is an important monitoring object of the substation online monitoring system. The end screen current of the transformer bushing is one of the important parameters to characterize the insulation state of the bushing, by collecting the full current of power frequency and partial discharge pulse current of the high-frequency domain. Based on the TMR array sensing principle, this paper studies the wide-band domain current sensing technology for the transformer bushing end screen current monitoring, and integrates it with the ground terminal of the bushing end screen to realize the sensing of the power frequency current and the high-frequency current of the bushing end screen. The detection bandwidth covers 50 Hz to 30 MHz. Power frequency current detection accuracy reaches 1%.
The topology-based approach to leakage current suppression on transformerless photovoltaic inverters
Authors: Su Li
Published: April 2023

With the increase in demand for renewable energy, photovoltaic power generation is gradually becoming the most promising new energy source. However, the electrical connection of PV cells to the grid, and parasitic capacitance between the PV cell and the ground can introduce severe leakage currents into the grid. The scientific community has developed various topology-based techniques to suppress leakage currents. This paper is dedicated to a review of these techniques. Firstly the H5, HERIC, FB-DCBP, oH5, H8, and H6 are analyzed. These techniques are then reviewed more fully in terms of quality, efficiency, size, and complexity. All six of these topologies can meet the requirements for leakage current suppression, and there is an increasing trend toward reducing the size and simplifying topologies. Finally, future trends in topology-based techniques for suppressing leakage currents are predicted. The significance of this paper is that it provides a comprehensive review and summary of the various topology-based techniques for suppressing leakage currents.
Research On Adaptive Sliding Mode Control of PMSM Based On Novel Reaching Law
Authors: Wang Yuxing , Liu Huibo
Published: April 2023

Based on the jitter and slow convergence speed caused by the conventional approach law SMC, a new exponential approach rate is proposed to optimize dynamic characteristics of the PMSM control system. The approach law is based on the conventional exponential adience law, and the variable of state the system are added. It can ceaseless adapt to the changes of the controlled system, ensure the high tracking function of the system and reduce the jitter caused by the control input. Meanwhile, based on the new exponential approach law, an self-adaption SMC is designed to estimate the uncertain parameters of the control process, and the stability of the make better approach law and control algorithm is analyzed by the function. Finally, The designed controller is compared with traditional sliding mode control and PI control through simulation experiments. The results show that the new exponential approach law can effectively suppress chattering and improve the dynamic characteristics of the system.
Offset compensation cable external diameter measurement system
Authors: Wang Qian , Song Jianyu
Published: April 2023

In the process of industrial production cables and pipes, the precise measurement of the produced product line diameter parameters is very important. In the present paper, we propose an offset compensation diameter measurement system based on analytical geometry and spatial coordinate transformation. The right-angle coordinate system is established in the corresponding planes of the two sets of charge coupling devices and the corresponding laser light source, and the center coordinates of the measured cable are obtained by the analytical geometric method, and the spatial coordinate transformation is used to connect the two coordinate systems to build the offset compensation measurement system. In the actual test (taking θ=45° as an example), considering the overall measurement results of the cylinder standard bar, the overall absolute error is between ± 4 μm without offset, and the relative error is 0~0.05%; and the relative average error (deviation angle is more than 0° and less than 35°) can be maintained at less than 0.7%. The above results demonstrate the feasibility of accurate measurement of this offset-compensated measurement system.
Power Grid Fault Diagnosis Method Based on LightGBM
Authors: Tao Guyuan , Wang Zirui , Zhang Xu
Published: April 2023

With access to distributed power generation and interconnection between regions, China’s power system structure is becoming increasingly complex, and the requirements for power grid dispatching capacity are getting higher and higher. When the power grid fails, a large amount of alarm information appears in the monitoring window, which needs to be processed and classified first to speed up the fault diagnosis and processing. Therefore, this paper proposes a power grid fault diagnosis method based on LightGBM. First, after pre-processing the power grid alarm information, Word2vec is used to vectorize the text, and then the LightGBM model is used to process the text, extract the information features and continue to train. Finally, realizing the three classifications of such simple faults as the transformer fault, bus fault, and line fault. Finally, through the test and verification of the actual power grid case data, it is verified that the method can effectively classify simple faults and meet the needs of the actual power grid online diagnosis.
A Faulty Line Selection Method for Flexible Grounding System Based on Transient Fault Data
Authors: Chen Ming , Xu Mingming , Wu Wenhao , He Yu , Wang Peng , Feng Guang , Dong Xuan
Published: April 2023

In view of the problem of high-impedance grounding faults (HIFs) in flexible grounding systems (FGS), a faulty line selection method based on transient waveform slope is proposed in this paper. The change of zero sequence (ZS) current of faulty line and non-faulty line (before and after the neutral point parallel small resistance are put in) are analyzed. After the parallel small resistance is put into operation, the waveform slope curve of the transient zero sequence current of each line is obtained, and the modified Hausdorff distance (MHD) algorithm is used to obtain the transient slope matrix. The faulty line is identified by comparing the sizes of each row of elements in the matrix. Simulation verifies the effectiveness of the proposed faulty line selection method.
Stability Analysis and Controller Synthesis
Authors: Lin Jinghuan , Liu Shangming , Meng Kelin
Published: April 2023

As the application market of voltage source inverters is consistently expanding, new control technologies are also being explored. This article presents a novel PIR controller using the conventional controller as a point of comparison and validated by tests conducted in MATLAB, the results of which led to the conclusion that the PIR controller has superior performance when compared with the traditional PI controller, R controller, and PR controller. These controllers are tested on a voltage source inverter system. In contrast to the conventional controller, the PIR controller demonstrates extra control flexibility through the Bode diagram and offers enhanced steady-state tracking capability. The analysis and comparison show that the PI controller does not have good dynamic tracking performance and cannot suppress the unbalance of secondary AC pulsation. The new control approach suggested in this paper may be implemented in the system to improve the system’s stability and dependability, increase the smoothness of the overall output, and assure the quality of the output.
Research on Traveling Wave Detection Performance Based on Optical Voltage Transformer
Authors: Zhang Ying , Zeng Jiachen , Jiang Zhuang , Yu Kun
Published: April 2023

Traditional transformers cannot effectively transmit high-frequency traveling wave signals, which leads to the fact that traditional voltage transformers cannot fully reflect the panoramic information of fault traveling waves and ensure fault location accuracy. This paper mainly analyzes the working principle of optical voltage transformers. The Jones matrix models the optical path system and its optical components, and the output model of the optical path system is obtained. The principle of photoelectric signal conversion is analyzed. The test principle, experimental method, and data results are studied and analyzed by power frequency, withstand voltage, lightning impulse, and arc tests. The transmission effect of fault traveling wave signal is verified, which provides the theoretical and experimental basis for the fault location of the distribution network.
Energy Coupling Control of Bridge Crane Based on Adaptive Fuzzy Strategy
Authors: Lu Haizhou , Ma Xianghua , Ye Yinzhong
Published: April 2023

Aiming at the problem that the traditional PID algorithm omits the nonlinear characteristics of the bridge crane system and the control effect is limited, this paper puts forward an energy coupling control strategy based on an adaptive fuzzy strategy. The coupling generalized semaphore for the Lyapunov controller is obtained by solving the dynamic equation of the bridge crane with energy, and the controller parameters are adjusted by using an adaptive fuzzy strategy. The simulation results show that the designed controller has a better anti-sway effect than the traditional PID controller.
Path Planning of Indoor Air Sampling Pipe in Substations Based on Fast Extended Random Number Algorithm
Authors: Han Jingang , Guan Yunlin , Li Yongqin
Published: April 2023

The substation is a fire accident-prone place, the substation fire automatic alarm system optimization design is an organic part of the fire safety work, and the substation air sampling pipe laying structure design method is an important link. In this paper, the substation model and sampling space are established, and the root node of the tree is searched by fast random in the RRT random algorithm to generate random sampling points and find out the path node nearest to the random sampling points. If so, the distance between the two points is less than the length, and the target point is considered to have been reached. This method can search the three-dimensional space quickly and solve the problem of the path planning of the air sampling pipe in the complex environment of the substation.
Optimization design of Three-phase balanced power supply for vehicle mobile power
Authors: Zhang Wei , Li Haiming , Bao Junyi , Pan Xiaobing , ZhibinWang  , Liu Peng
Published: April 2023

This paper analyzed the harm of three-phase unbalanced power supply of vehicle mobile power supply to generator set electrical equipment and communication system, and the cause of the harm is analyzed. The three-phase balance control box is designed by adopting the design concept of “three input one output” and “rectifier inverter”. Through the comparison of the experimental data, the feasibility of the three-phase balance control box for the three-phase balance adjustment of the external power supply of the vehicle mobile power supply is verified, so as to achieves the optimization of the three-phase balance power supply and improves the reliability and safety of the external power supply of the vehicle mobile power supply.
The magnetoresistance acquisition system of a perpendicular magnetic tunnel junction using LabVIEW software
Authors: Rahman N. , Sbiaa R.
Published: April 2023

For accelerated productivity, and continual innovation in the field of spintronics, the electrical characterization of the magnetic tunnel junction (MTJs) is of paramount importance. This report deals with the testing of the MTJs. It focuses on the design of an experimental setup with data acquisition of the MTJs with perpendicular magnetic tunnel junctions where a high magnetic field aligned perpendicular to the film plane is required. Furthermore, devices with very small electrodes of only a few micrometers in lateral size can be tested. A computer through a LabVIEW program controls the data acquisition system.