bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on the influence of the number of guide vane blades on the flow characteristics of axial flow pump
Authors: Changsheng Chen , Shan Li , Haitao Li , Zhenlai Ma , Qiang Wang
Published: August 2021

Axial flow pump is widely used in energy, agriculture, urban water supply and drainage, water conservancy engineering, ships and other fields. As one of the important flow passage parts of axial flow pump, guide vane can be used to smooth the rotation of fluid after passing through the impeller, change it into axial motion, and change the kinetic energy of rotation into pressure energy. In this paper, the hydraulic performance and pressure pulsation of axial flow pump with three different guide vane numbers are analyzed by numerical simulation. Under rated flow and large flow conditions, increasing the number of guide vanes is more conducive to suppress the pressure pulsation.
Fabry Perot Cavity Length Demodulation Method Based on Continuous Thinning Algorithm of Fast Fourier Transform Spectrum
Authors: Yu Jiawang , Bian Qiang , Tong Yude , Zhu Zhen
Published: August 2021

Optical fiber Fabry Perot sensors are widely used in industrial production and life. It is of great significance to improve the performance of sensor demodulation algorithm. Based on the analysis of the principle and error source of the cavity length demodulated by the Fast Fourier Transform (FFT) algorithm, the FFT-FT algorithm with continuous refinement of FFT spectrum is introduced. By using the feature that FFT-FT algorithm can refine at the peak of discrete spectrum, the length of F-P cavity demodulated by FFT algorithm is optimized to improve the accuracy of the demodulation. Through simulation experiments, the F-P cavity length of FFT demodulation algorithm and FFT-FT demodulation algorithm under the same light source signal are compared and analyzed, and the goodness of fit of the fitting curve of continuous demodulation is analyzed. The simulation results show that the error of FFT demodulation algorithm is more than 100 times that of FFT-FT algorithm when it is refined 100 times near the peak value of FFT discrete spectrum. The goodness of fit of the demodulation fitting curve calculated by FFT-FT algorithm is more than 2 times that of FFT algorithm, which proves that the improved algorithm demodulation F-P cavity length value has better consistency with the real value.
Research on voltage restoration of island microgrid based on multi-agent fixed-time algorithm
Authors: Zhuang Yan , Zhao Yan , Wei Mofan , Liu Qian , Shao Qianzhi
Published: August 2021

This paper presents a distributed, robust and fixed-time secondary control for voltage restoration of an islanded microgrid with droop-controlled inverter-based distributed generators (DGs). The network inverter of AC microgrid is set as a multi-agent cooperating system, and voltage recovery can be regarded as a synchronization problem. Different from the existing distributed methods, the method in this paper can ignore the dependence on the initial conditions and the distributed controller based on consensus can restore the voltage magnitude of the island microgrid to the standard reference value in a fixed-time. In order to improve the stability, a fixed-time second-order convergent sliding mode surface is proposed. This method can quickly reach a consensus and has better anti-interference ability and robustness. Finally, the performance of the proposed control strategy is verified.
An improved gravitational search algorithm for distributed generation optimization
Authors: Yuan Zeng , Chen Guochu
Published: August 2021

In order to optimize allocation and sizing of distributed generation, this paper puts forward an improved gravitational search algorithm based on particle swarm optimization. For the sake of preventing the gravitational search algorithm from falling into local optimum, mutation is added to the formula of position, and only Kbest particles are searched. The objective function to be optimized is the minimization of the power losses, and the IEEE-33 bus system is adopted to test the efficiency of the improved algorithm. The results indicate that the improved gravitational search algorithm has better convergence accuracy than the basic gravitational search algorithm, and that the voltage of the system can be improved.
Research on night vision distance imaging technology of semiconductor laser
Authors: Wang Zhaoxin , Zhai Yannan , Yang Kun , Gao Ling , Li Jing
Published: August 2021

The semiconductor laser night vision distance imaging system introduced in this paper is an active imaging system with a laser as a light source, forming an image according to the light reflection difference of the target and the background. Compared with the passive imaging system, the active imaging system has the characteristics of strong receiving signal. Under extreme conditions, it can also realize the extraction of image key information of strong reception signal. Under extreme conditions, it can also realize the extraction of image key information through range-gated technology. It is a high anti-interference capability semiconductor laser ranging imaging technology suitable for severe weather and conditions. The system can be used in laser active imaging guidance, unmanned aircraft, guidance systems and other military fields and public security, fire control, transportation and other fields.
Research on Transformer Condition Recognition Based on Acoustic Signal and One-dimensional Convolutional Neural Networks
Authors: Yuchao Ma , Wang Xin , Zhou Wenjin , Xiang Li , Juan Mo , Zhongyuan Zheng
Published: August 2021

To solve the problem of transformer condition recognition, this paper propose a transformer condition recognition method based on acoustic signal and One-dimensional Convolutional Neural Networks(1D-CNN). In order to verify the effectiveness of 1D-CNN algorithm in the field of transformer condition recognition, a platform for acquisition of acoustic signals from a 500 kV transformer is built to carry out the acoustic signal acquisition test for four conditions of the transformer. The acoustic signal data sets are also made, and the 1D-CNN algorithm is used to calculate the recognition accuracy of the transformer conditions. According to test results, 1D-CNN algorithm, as a new structure of deep-learning algorithm, can properly classify acoustic signals of the transformer, and its classification accuracy is higher than those of FFT-BP, SVM, FFT-SAE and other algorithms. In order to explore the internal mechanism of 1D-CNN algorithm, in this paper, a t-SNE visual analysis is also conducted to reveal the performance of 1D-CNN algorithm.
Development of efficient testing algorithm for hydraulic valve group
Authors: Liu Chang , Wang Zhe , Xing Keli , Jin Xiajie
Published: August 2021

Based on the principle of flexible testing technology, the test software is designed hierarchically and modularized. By calling the optimization algorithm of the test process, the automatic combination of the test process and the package call of the basic unit program of the test, the optimal sequencing and flexible configuration of the valve group test process are realized, and the efficiency of the automatic test scheme of the valve group is effectively improved. The test results show that the optimized test scheme can reduce the test time by 14.8% ∼ 34.6% and the test energy consumption by 9.0% ∼ 11.2%.
Optimal dispatch of multi-virtual power plants based on Grey Wolf Optimization algorithm
Authors: Li Yingliang , Zhou Liwen , Gao Zhaodi , He Kun , Cai Heming , Sun Xiyao
Published: August 2021

The day-ahead scheduling of virtual power plant (VPP) is of great significance for the development of distributed generations. To solve the problem of large-scale VPP scheduling, this paper proposes a multi-VPPs optimal dispatching strategy. In this model, the VPP is divided into multiple sub-VPPs, and each sub-VPP scheduled internally. Likewise, the power interaction between each sub-VPP at the contract price is allowed. This model can realize complementary power, and hence maximize economic benefit of VPP and also improve the level of new energy consumption. Then, to solve this nonlinear optimization problem, Grey Wolf Optimization (GWO) algorithm is employed. Finally, the proposed model is tested through a detailed case study, and results demonstrate that the GWO algorithm can improve the computational efficiency.
Research on intelligent somatosensory interaction devices based on virtual reality technology
Authors: Li Xinyi , Gan Baiqiang
Published: August 2021

Contemporary students have developed a dependence on electronic devices and developed the habit of sitting with screens for a long time, which has led to a trend of gradual deterioration of health conditions, declining physical quality and rejuvenation of diseases. Therefore, in this paper, based on the interactive and experiential characteristics of intelligent somatic interactive devices with virtual reality technology, the intelligent somatic interactive device body is improved according to the functions of virtual reality device body shape and experience, based on the handling needs, experiential needs and functional needs, and the educational interactive device experience strategy is designed to meet individual needs for the student group, and through comparison experiments with two groups of students, it is concluded that The interactive device experience strategy proposed in this paper outperforms the comparison group in terms of learning interest, motor interest, psychological anxiety, and emotional communication, verifying the effectiveness of the interactive device experience strategy, thus promoting students' physical health and improving individual physical signs, and also providing reference and learning for researchers engaged in intelligent somatic interactive devices based on virtual reality technology, from form design to development ideas.
Three-dimensional attitude determination using vector observations and optical flow sensors
Authors: Xiang Li , Peng Zhang , Qi Shi , Yanmei Tang
Published: August 2021

Flight control of unmanned aerial vehicle relies on three-dimensional attitude determination, and the most commonly used solution is based on the combination of magnetometer, accelerometer, and gyroscope, namely the MARG sensor. Optical flow sensor is also widely applied on UAV to detect the motion of UAV relative to the ground. In this paper, we proposed a novel method that using multiple optical flow sensors to measure angular velocity. This method utilizes a linear model to resolve both linear and angular motion from the measurements of multiple optical flow sensors. In the case of in situ rotations, experiment results prove that the proposed method can effectively estimate the angular velocity, and it can be used to augment MARG-based attitude determination.
Design of intelligent kitchen waste sorting machine based on Pro/E and Adams
Authors: Jiang Haoyuan , Wang Yuchun , Wu Yuxuan , Li Xurong
Published: August 2021

In order to effectively solve the problem that the subsequent waste treatment is affected by foreign bodies such as bones and hard shells in kitchen waste, reduce the treatment cost and improve the utilization efficiency of kitchen waste, this paper designs a small kitchen waste Intelligent Classification Recycling and reprocessing device which can be applied to school canteens, communities and township waste treatment plants. The device is mainly composed of mechanical body, central processing unit, detection and sensing system and post-processing system design. It can further separate kitchen waste on the basis of solid-liquid separation, realize reprocessing and recycling, and maximize the recycling value of kitchen waste, so as to achieve the purpose of energy conservation, emission reduction and sustainable development.
Research on pattern recognition technology for a highperformance optical fiber vibration sensor
Authors: Min WANG , Jiantao ZHENG , Teng ZHOU
Published: August 2021

In this paper, the optical fiber vibration sensor based on Mach-Zehnder Interference (MZI) principle is designed and researched, which can improve the ability to recognize the physical intrusion events for underground power pipelines by means of pattern recognition technology. Through data collection, analysis and processing, the vibration event database of key intrusion events in typical environment is established. By using coherent optical beat frequency, vibration recognition algorithm, machine learning and other technologies, the frequency domain diagram and time domain diagram of different vibration signals are analyzed and judged. In the end, the feature values of optical fiber vibration sensor such as frequency range, amplitude and waveform density are extracted.
The Critical Technical Research on the Intelligent Control Management System of the Energy Station
Authors: Xianxian Chen , Xiaoguang Liu
Published: August 2021

According to the currently equipment characteristics and process requirements of the refrigeration system of the energy station, we implement intelligent control energy-saving renovation project, which realized the automatic and intelligent control and operation of the refrigeration system related equipment. The system uses distributed control system, and provides systematic solutions for scientific decision-making, reasonable dispatch, energy management, energy efficiency analysis and energy-saving control. Simultaneously, to improve energy efficiency, this system can make full use of the electricity price policy, maximize the economic benefits of water storage, and operate in the lowest cost mode of energy supply.
Design of integrated management and control system for geological disasters of transmission lines based on GIS
Authors: Dan-dan Liu , Wei Hu , Jian Zhao , Yu You Po , Ping Zhao
Published: August 2021

The geological environment of Guizhou Province is fragile, which is one of the most serious geological disaster areas in China. Frequent geological disasters have seriously affected the safe and stable operation of domestic transmission lines. At the same time, it has the system of detection, decision-making and security protection, which is still blank. Therefore, this paper uses database technology and GIS technology, first of all, clean up and integrate the data of transmission line, major geological disasters and hydrometeorology to establish a comprehensive database of transmission line geological disasters. Then, the risk assessment model of major geological disasters of transmission lines is established to extract the risk level information of major geological disasters of transmission lines and formulate differentiated operation and maintenance strategies. Finally, the integrated management and control system of transmission line geological disasters is designed to realize intelligent detection and decision-making of geological disasters, so as to prevent and reduce the losses caused by geological disasters and ensure the safe operation of power energy.
Research on improving transient voltage stability of wind power grid connected system by SFCL and STATCOM
Authors: Tao Cheng , Kuang Honghai , Kuang Wei , Su Fuqing
Published: August 2021

Aiming at the problem of transient voltage instability in the grid-connected wind power system, a combined method of superconducting fault current limiter (SFCL) and static synchronous compensator (STATCOM) was proposed to suppress voltage saps. In this method, a superconducting fault current limiter (SFCL) is connected in series on the transmission line, and a static synchronous compensator (STATCOM) is connected in parallel on the bus of the wind farm. SFCL shows zero impedance when the system is in normal operation, and quickly shows high impedance when the fault occurs, so as to effectively suppress the short-circuit current and provide the bus voltage support. At the same time, STATCOM provides reactive power during the fault period, so that the system voltage can quickly recover. By establishing the corresponding simulation model, SFCL and STATCOM are used to jointly improve the voltage stability of the wind power grid-connected.
Optimization method of external power transmission based on complementary characteristics of wind power and photovoltaic
Authors: Yang Jingying , Lu Yu , Li Qunying , Liu Peng , She Xin , Zhang Yuanmei
Published: August 2021

The large-scale development of renewable energy power is faced with challenges such as the reverse distribution of wind and photovoltaic resources and power loads. The main challenge currently facing is the randomness and volatility of renewable energy power generation. Based on the concept, this paper studied the bundled transmission capacity planning. First, this paper proposed new energy output characteristics based on probability theory. According to the historical data of wind power and photovoltaic power generation, this paper considered the timing output characteristics and output change characteristics of wind power and photovoltaic power generation under different time scales. Then, the optimization model is established based on the objective function of minimizing total cost. Finally, this paper solved optimization problems with reinforcement learning algorithms and determined the installed capacity of thermal power. The research results of this paper have a certain significance for the bundled delivery of wind power and photovoltaics in new energy-rich areas.
Application of new intelligent double end grounding circuit breaker circuit resistance measurement technology
Authors: Dongpeng Sui , Fucu Huang , Chang Liu , Ye Zhao , Yanan Wang , Zhinan Guo
Published: August 2021

According to actual needs of the circuit breaker field measurement, by using induction coil as the basic principle of the proposed at both ends of the breaker is connected with the loop resistance test method. In this paper, we mainly study the circuit breakers at both ends of the ground state, circuit breaker loop resistance test design principle and theory model, solution method for the measurement of the small current signal criterion, research and development of the testing device, and through the two ends of the two devices on circuit breaker and GIS combination electric appliance grounding field test. Finally, to test this method and the traditional methods of test results were compared and analyzed, it is concluded that the two ends of the grounding circuit breaker loop resistance method can completely meet the needs of field maintenance and can improve the detection accuracy and instead of the traditional test methods.
Double closed-loop PI controller tuning for motor control
Authors: Huang Shixuan , Tu Feng , Guo Qijun , Wu Binyu , Huang Zhifan , Chen Haigen
Published: August 2021

This paper demonstrates an algebraic algorithm performed in the control loop of a Brushless DC Motor (BLDCM) speed controller by computing the PI controller parameter that can be accepted. Using methodology of PI controller stability analysis, accurate stability conditions can be derived for the BLDC Motor speed controller. The results of applying the new method ensure the system stability and fast response by tuning the PI controller in the order of the motor and mechanical constant.
Research on voltage reactive power optimization considering fuzzy load characteristics
Authors: Huo Chengjun , Wang Weiru , Li Mengzan , Liu Xinyuan
Published: August 2021

For the distributed load output is uncertain, which leads to the over-limit of voltage and line power, this paper proposes a load representation method based on fuzzy set theory, and establishes a voltage reactive power optimization model based on fuzzy number. The influence of different control equipment on node voltage and reactive power is analyzed. Combined with the sensitivity analysis method, the selection rules of control equipment with heuristic method are developed. A method of Genetic calculation based on fuzzy power flow calculation is presented. Finally, this method is applied to build a 30-node model in Matlab for simulation calculation. The results of the example show that the proposed model and method can accelerate the convergence speed, reduce the solution space and reduce the network loss.
Prediction and Simulation Analysis of Current Turn-off Behavior of Low-Voltage DC Circuit Breaker
Authors: Wu Yuebin , Hou Lei , Qi Tianxing , Ma Tao , Kong Yuhui , Li Mei , Zhang Rui
Published: August 2021

As the key breaker of hybrid DC circuit breaker, IGBT is the research focus of hybrid DC circuit breaker.In this paper, a steady state simulation model of IGBT is built based on the Darlongton equivalent structure.Through the actual output characteristics of IGBT, the feasibility of the steady-state simulation model of IGBT is verified.Then, a driving simulation model considering the positive and negative bias of IGBT drive output is built.In order to establish a more accurate transient model of IGBT, a semi-empirical MOS3 model considering weak inverse conductivity is adopted in the MOSFET model and a Gummel-Poon model considering multiple secondary effects is adopted in the BJT model.According to the experimental data, the feasibility of IGBT transient model is verified, and the construction of IGBT transient model under the DC breaking condition is completed.
Research Status of Dust Reduction Technology in Coal Handling System of Thermal Power Plant
Authors: Xing-ding Xia , Yong Yang , Yu-nong Sun , Yi-dan Zhang
Published: August 2021

Aiming at the dust control of coal handling system in thermal power plant, the research status of dust reduction related theory and technology was summarized. This paper introduced the research progress of dust and air separation mechanism and multiphase flow simulation technology in dust removal and suppression, as well as the features and application of dust removal technologies such as wet dust suppression, bag type dust removal, high voltage electrostatic dust removal, unpowered dust reduction and others. The technical route of dust reduction in coal handling system of thermal power plant was advised, which provides reference for dust control in coal handling system.
Medium and long term wind power generation forecast based on OWA combined model and Markov chain
Authors: Gong Ze , Xu Qifeng , Xie Nan
Published: August 2021

Wind energy, as one of the renewable energies with the most potential for development, has been widely concerned. At the same time, the medium and long term wind power prediction is easily affected by many factors. In order to avoid the instability of a single model, this paper first builds a self-adaptive filtering model and a gray model with parameter optimized by teaching learning-based optimization (TLBO), then uses ordered weighted averaging (OWA) to assign weights to two single models, and finally uses Markov chain to modify the prediction results to further improve the prediction accuracy.
Stochastic optimization model for integrated energy system under uncertainty based on chance-constrained programming
Authors: Li Baoju , Sun Yong , Li Xu , Zhang Ruosi
Published: August 2021

To solve the day-ahead optimal dispatching of the integrated energy system (IES), the influence of uncertainties in the operation is taken into consideration, and the application of combined heat and power (CHP) and Power to Gas (P2G) equipment can improve the system’s ability to accommodate renewable energy and reduce system operating costs. In order to minimize the operating cost of IES, a mixed-integer linear programming (MILP) optimization model based on chance-constrained is proposed in this paper. A scenario-based simulation method is proposed to convert the chance-constrained programming (CCP) model into a deterministic one. The model in this paper can effectively reduce the risk of system operation in uncertain environments and improve the stability of system operation.
A Method for Calculating the Internal Magnetic Field Distribution of the Modular Multilevel Converter Valve
Authors: Zhang Zhixin , Jiao Chongqing , Du Rongtian , Yang Yong , Wang Jialong
Published: August 2021

This paper presents a simple calculation method for the magnetic field distribution in the converter valve tower of the DC transmission system. The current inside the IGBT is decomposed into the superposition of the low-frequency sinusoidal current and the high-frequency spike current. According to the shielding mechanism of the metal shielding layer at different frequencies, the original model is divided into two sub-models. Then the final result is the superposition of the results calculated by the two sub-models. This method can calculate the magnetic field distribution in the converter valve tower in a short time.
Research on Statistical Method of Distribution Network Reliability Based on Dispatching Operation Management
Authors: Yuying Wang
Published: August 2021

Distribution network reliability statistics have always been an important indicator of the effectiveness of distribution network construction. In view of the characteristics of traditional manual statistics, such as heavy workload, low efficiency and poor accuracy, this paper starts from the demand of reliability analysis and combines with dispatching management system to realize automatic collection and recording of operation data related to reliability. Finally, according to the actual situation of the project site, a variety of distribution network reliability statistical methods are proposed.
Research of Modulation and Control Strategy of Modular Multilevel Inverter
Authors: Chang Yating , Xu Xianglian , Yin Xiaobei , He Yu
Published: August 2021

As a new multilevel converter structure, modular multilevel converter (MMC) has many outstanding advantages, such as high degree of modularization and easy cascade expansion, which greatly promotes the development and application of flexible DC transmission technology. In this paper, the modular multilevel inverter is the main research object, its topology and multilevel generation mechanism are analysed, and the capacitor voltage of sub modules is balanced based on the carrier phase shifted PWM strategy. The MMC simulation model is built on the MATLAB/Simulink software platform. According to the simulation results, the feasibility of the modulation and control strategy in reducing the harmonic component of output voltage and maintaining the stability of capacitor voltage is verified.
Electromagnetic simulation and test based on shielding effectiveness of cabinet shell
Authors: Gao Tongguo , Wang Tao , Li Deng , Guan Yu
Published: August 2021

Electromagnetic simulation technology is an important means to study microwave electromagnetic field and electromagnetic compatibility. The shielding effectiveness of electronic cabinet made of carbon fiber materials is studied by simulation method. The mainstream 3D full wave electromagnetic simulation software CST and modern electromagnetic simulation algorithm are used as research tools to analyze the shielding effectiveness of electronic cabinet made of carbon fiber materials. The simulation results are verified by means of scaled model verification, which greatly reduces the cost of experimental verification and improves the research efficiency.
Reliability Assessment of Distribution Network Considering Multiple Types of Cyber Disturbances
Authors: Guiping LI , Shuyuan ZHANG
Published: August 2021

The improvement of power grid intelligence depends on the development of communication technology. The wide application of communication technology in power grid has brought new security threats. In order to comprehensively and quantitatively evaluate the impact of external threats and cyber element failureson power supply reliability in the whole process of distribution network operation, reliability state models of different types of cyber disturbances are proposed, the impact of different types of cyber disturbance on the cyber availability is analyzed and a framework of distribution network reliability evaluation considering multiple types of cyber disturbance is constructed. Finally, the simulation test of IEEE33 bus distribution system verifies the feasibility and effectiveness of the proposed model and method.
Infrared time-sensitive weak and small target detection method based on density search and gradient decision
Authors: Liu Chuang , Yang Xiaogang , Lu Ruitao , Gao Fan
Published: August 2021

For detecting infrared time-sensitive weak and small targets in a complex air-ground background, it is easy to be interfered by low signal-to-noise ratio and strong noise. In this paper we proposed an infrared time-sensitive weak and small target detection method based on density search and gradient decision. First, we use adaptive wiener filtering to preprocess the infrared image to reduce noise interference; then, use the density peak search method to extract points of interest, and use the eight-directional gradient method to make decision-making judgments; finally, use the adaptive threshold segmentation method to extract true targets. The experimental results show that this method has good robustness and detection performance for single infrared time-sensitive weak and small target detection in the air-ground background.
Research on optimization of ship’s automatic berthing and unberthing control model
Authors: Zhou Hongmao , Shi Hankun , Zhu Shenchao , Wang Xuelin , Zhang Zhaolun
Published: August 2021

The automatic berthing and unberthing of ships is one of the very important links in the process of ship navigation. Due to the relative increase of interference from external factors such as wind, waves, currents, and the relative increase in system information, the automatic berthing and unberthing operations are more complicated. Traditional control methods have been difficult to meet the technical requirements of automatic berthing and unberthing. This research created a control model for automatic berthing and unberthing, optimized the parameters of the created control model, performed parameter identification on the ship model, and tested the established mathematical model. The test results met the requirements for automatic berthing and unberthing. It provides a good reference value for the future development of automatic berthing and berthing.
Early fault detection for power plant fans based on dynamic neural network
Authors: Zhang Guobin , Du Ronghua , Xin Xiaogang , Zhao Wei , Dang Shaojia , Zhao Song , Yun Pei
Published: August 2021

Early fault detection is increasingly important for the reliable and secure operation of power plant fans. In this paper, we propose an early fault detection strategy for power plant fans based on dynamic neural network. First, the nonlinear autoregressive (NARX) with exogenous inputs network is utilized to predict the behavior of fans by using normal operating data, and the discrete particle swarm optimization (DPSO) is utilized to optimize the hyper-parameters of NARX network to enhance prediction accuracy. Then, the fault alarm strategy is proposed by the prediction deviations and generalized extreme value (GEV) theory. Finally, the proposed method is applied to a forced draft (FD) fan in a coal-fired power plant. Experiment results show that the proposed model has high prediction accuracy on normal operations and produces large prediction errors when a failure occurs. Furthermore, it can detect early faults accurately and timely before the failure occurs.
Research on Yaw Error Detection of Wind Turbine Based on Particle Swarm Optimization
Authors: Zhang Xinyue , Yang Chenghu , Li Xinrui , Yan Daqiang , Li Hai
Published: August 2021

Yaw system is an important part of the wind turbine, one of its main functions is to automatically face the wind when the wind turbine is in normal operation, to ensure that the engine room is facing the wind direction, so that the wind turbine can make efficient use of wind energy. However, the yaw system can not guarantee the accuracy at all times, which leads to the wind deviation. Too large deviation of wind energy not only reduces the efficiency of wind turbine using wind energy, but also leads to abnormal wear of equipment parts, which is not conducive to the normal operation of the unit. In this paper, a wind turbine deviation detection algorithm based on SCADA data is proposed. The detection algorithm mainly includes wind speed segmentation, data fitting, particle swarm optimization and other key technologies. After wind field verification, the algorithm proposed in this paper can effectively detect the wind deviation of wind turbines, and help to improve the efficiency of wind turbines.
Study on Reliability Improvement of Main Steam Isolation Valve Control in Nuclear Power Plants
Authors: Gan Changxian , Wan Tian , Pan Weiwei , Liu Shengzhi , Tang Lei , Li Huahuan
Published: August 2021

There is a safety hazard in the interlock control logic of the second circuit main steam isolation valves of the CPR1000 nuclear power unit. During reactor power operation, any abnormal full-close limit switch signal of valves may lead to a reactor shutdown event or even a Safety Injection of nuclear reactor. In this Paper, the control strategy of the second circuit main steam isolation valves is analyzed and demonstrated, and after Probabilistic Safety Assessment(PSA), a feasible improvement plan is proposed, which effectively improves the control reliability of the second circuit system in nuclear power plants.
Research on Control Design on PMSG Based on LSTM
Authors: Wang Qi , Hu Hongbin , Yuan Shuai , Miao Lifang
Published: August 2021

The traditional control method of permanent magnet synchronous generator (PMSG) needs multiple rounds of tuning and test to ensure the dynamic characteristics of the PMSG to reach the standard. It is complex if there are a large number of PMSGs needs to design parameters of the control loops. In order to simplify the tuning and testing process of the control parameters of the PMSG, a data-driven based control method of a PMSG is proposed in this study. It can fit the standard dynamic characteristics by learning the inputs and outputs of the standard dynamic response curves using the long short term memory LSTM method. Subsequently, the proposed control method can be applied to multiple PMSGs, which is convenient and no staff is involved. Finally, a power system connected with a PMSG is as an example. It demonstrates that the dynamic of the PMSG adopted the proposed control method is same with that of the standard PMSG.
Research on Monitoring System of Cable Joints of Ring Network Cabinet Based on Wireless Temperature Sensor
Authors: Shang Shuning , Liang Guangsheng , Xiao Wei , Ya Hougui , Chen Shuqi , Yu Jie , Chen Zhongbin
Published: August 2021

In this paper, a state monitoring system for the cable joints of the ring main unit is constructed based on the passive wireless temperature sensor. Considering the sensor packaging structure and housing material, a temperature sensor that can meet the monitoring requirements of the T-shaped insulating sheath of the cable joint is designed. Based on the thermal circuit method, the real temperature value of the internal cable joint is calculated by using the outer surface temperature of the T-shaped insulating sheath to provide more accurate data for monitoring and early warning. The background monitoring software of the monitoring system is designed to realize the temperature of the T-shaped cable joint in the ring network cabinet. Online monitoring and abnormal early warning facilitate the operation and maintenance personnel to take timely measures, which can effectively improve the operation and maintenance efficiency of the ring cabinet of the distribution network and ensure the reliability of power supply.
A method of fault detection of casing lead based on CEEMDAN-LMD
Authors: Hao Chenggang , Sun Woye , Zhang Jiguo , Li Kai , Wang Xin
Published: August 2021

The existing regular inspection tests for the deformation faults of the bushing lead have the problem of offline detection and poor sensitivity. In order to effectively extract the high frequency components of vibration for diagnosis and analysis, a new fault diagnosis method for the transformer bushing lead is proposed. This method decomposes the time-domain waveform of the collected ultrasonic echo signal through CEEMDAN, and reconstructs its high-frequency components according to the entropy weight method to obtain a denoising signal, and then performs LMD decomposition of the denoised signal, and decomposes the denoised signal. The PF component is analyzed as the input feature component. The method of ultrasonic inspection of casing lead in this article has good adaptability, can obtain lead fault location results with high precision and good reliability, low hardware cost, and good application prospects.
Hydraulic motor constant low speed characteristics measurement study
Authors: Nie Yueyue , Niu Yuxiang , Xing Keli , Jin Xiajie
Published: August 2021

Due to the special characteristics of hydraulic motors, the minimum stability characteristics are often one of the important characteristics to be considered in hydraulic system applications. In this paper, based on the analysis of the hydraulic mathematical model of the axial piston hydraulic motor, the model of the axial piston motor is established by using AMESim simulation software, and its low-speed characteristic curve is output through simulation to verify the validity and reasonableness of the low-speed characteristic testing scheme of the hydraulic motor. Finally, a hydraulic motor constant low speed characteristic test system is built based on LabVIEW software, and a field verification test of the hydraulic motor constant low speed characteristic is carried out, which provides some engineering reference value for the hydraulic motor constant low speed characteristic test.
Design of defect detection system for semiconductor plastic packaging based on machine vision
Authors: Niu Zanyao
Published: August 2021

At present, the ability of defect detection system to detect the position of semiconductor plastic packaging defects is poor, so a defect detection system of semiconductor plastic packaging based on machine vision is designed. In terms of hardware, based on machine vision technology, the system framework is determined, the camera, lens and light source models are selected, and the detection target image acquisition parameters are determined. In terms of software, according to the target image obtained by machine vision technology, the image is preprocessed, segmented and feature extracted to identify and detect the target image and detect the semiconductor plastic packaging defects. Experimental results: compared with the system selected in this experiment, the design system can accurately detect the defects in the semiconductor plastic packaging and the location of the defects.
Changes of Urban Greenness Based on Sentinel Data and Landsat Data
Authors: Bi Xinrui
Published: August 2021

With the rapid growth of the global economy, environmental resources have also been severely consumed and destroyed. With the rapid growth of China’s economy, domestic environmental pollution and environmental damage have become increasingly serious. In order to understand the changes in the urban greenness of Chinese cities, the changes in the urban greenness of coastal cities in China in the past five years have been explored by using Landsat satellite remote sensing image data from multiple periods since 1973. The reason for choosing coastal cities as the research objects is that the coastal cities have relatively developed economy and have certain demonstrative significance for both themselves and the development of inland cities. This article first popularizes the domestic urban environmental conditions and knowledge of remote sensing technology, and then analyzes the process of obtaining urban greenness sentinel data and Landsat data of coastal cities from remote sensing data, and finally analyzes the urban greenness of coastal cities in the past 5 years. The increase change and the average increase change are analyzed and compared, and corresponding conclusions are given based on the analysis results.
Simulation Modeling Practice on Occupant Evacuation in a Medium-sized Supermarket
Authors: Han Tingting , Chen Dong , Chen Leiyu
Published: August 2021

The research mainly focused on the effect of staff density and exit conditions on total evacuation time. The results showed that with the increase of staff density, evacuation time often increases non-linearly. The function equation of evacuation time and number of occupants in case A was obtained through computer simulation. The augment of exit number or total export width can reduce the total evacuation time to improve evacuation efficiency. While, if the number of evacuees reaches to a certain value, evacuation time may increase non-linearly after being affected by the internal structure and the random distribution of occupant. Export position also has impact on total evacuation time. The results of the simulation have guiding significance on the design of building structures and personnel evacuation in emergency.
Routing in Delay-tolerant network Based on Nodes’ Sociality
Authors: Tan Long , Men Zixuan
Published: August 2021

To solve the problem of low ratio success delivery, long latency caused by the rapid dynamic change of network topology, limited node buffer, large amount of data transmission and large user population density in delay-tolerant network (DTN). This paper propose a routing algorithm in DTN based on nodes’ sociality. In this paper, contact history was used to determine the node link quality; Markov model was used to predict the node position based on the nodes’ movement track; according to nodes’ social similarity to divide community, then calculated node betweenness centrality. Finally, the best forwarding nodes for message transmission were determined. Besides, to increase the ratio of successful delivery, message delivery probability in the relay node’s buffer was calculated. Experimental results show that compared with traditional routing algorithm, the proposed algorithm performs better on the delivery ratio and average end-to-end delay.
Research on key Technologies of 5G Mobile Communication D2D
Authors: Jin Jin , Zhao Lipeng , Zhang Guoquan , Zhang Shenguo , Jiang Kun
Published: August 2021

As one of the main technologies of 5G, device-to-device (D2D) technology directly transmits data between mobile terminals in the adjacent area, and there is no need for base station relay equipment to transfer, so as to realize high data rate transmission, improve communication capacity, reduce transmission delay, and make full use of wireless spectrum resources. With the support of D2D technology, cellular wireless communication can be avoided between devices, so that wireless communication can be realized without occupying the bandwidth resources. In this paper, with the support of D2D technology, firstly, the transmission path optimization of D2D technology is realized by artificial swarm algorithm. Secondly, the simulation is carried out by MATLAB software. Finally, the path optimization of D2D communication is realized by simulation, and the test results are compared and analyzed.
Research on ocean current visualization method based on particle
Authors: Dong Yong , Huang Binghu , Wang Fuyuan , He Yawen
Published: August 2021

NetCDF network general data format is a common data format used to store meteorological data such as ocean current field. However, the ocean current data in NetCDF format can not be read directly on the web for dynamic visualization. To solve this problem, this paper takes the Pearl River Estuary area as the research area, adopts the sparse algorithm based on local Moran’s I index and improved point center buffer to dilute the ocean current data, converts the ocean current point data into particle data by using the vector synthesis calculation method of ocean current data, and designs specific JSON data structure for data storage. After completing the pre-processing of the visualization data of ocean current based on particles, a dynamic visualization display platform of ocean current particles is built on the Web side, and the JSON data of ocean current is read. The space-time dynamic visualization effect of ocean current data in the form of particles in the format of NetCDF is realized, and the static and intuition problem of ocean current visualization is solved.
Construction of High-standard Farmland Geographic Information System
Authors: Chen Yonghua , Chen JiaWei
Published: August 2021

At present, the management of high-standard farmland is only managed at the county level, and data reporting is done by the county in the form of reports, which cannot form a unified data sharing model, resulting in low efficiency in daily management. The comprehensive management system of high-standard farmland designed in the thesis can completely solve the problem of non-uniform management and provide a comprehensive management, query and statistical summary platform with unified data and intuitive image.
Remotely sensed modelling of urban spatial-environmental health across 32 major cities in China
Authors: Zhang Ping , Sun Yifu , Sun Qiangqiang , Sun Danfeng , Zhang Yongxiang , Li Hong , Li Rui
Published: August 2021

The timely and effective evaluation of spatially-explicit urban PM2.5 concentrations is highly important for an improved understanding of urban environmental health and sustainability in China. However, recent studies examining the spatiotemporal patterns of PM2.5 concentrations has not been comprehensively clarified due to the absence of spatial-detailed urban landscape linkage. In this study, a general non-linear model was developed to depict the non-linear relationship between spatially explicit impervious surface area (ISA) fractions and associated PM2.5 concentrations gradient changes for individual cities from multi-source satellite-based dataset. The comparative results of environmental quality across 32 major cities in China showed that the spatial pattern of urban PM2.5 concentrations is correlated with geographical orientation and socio-economic clusters—high baseline and more balanced states of PM2.5 concentrations are prevalent in North China and the Yangtze delta agglomerations. Temporally, during the period of 2000-2018, most of cities have the path dependency, whereas high concentration of PM2.5 diffused from the original east of ‘Hu-Huanyong Line’ toward some cities in north-eastern, central and western regions. In addition, our study highlights the optimizing regional economic structure and promoting urban greening construction will be of great significance in sustainable urban environmental health management.
Deep Space Exploration Strategy Based on Distant Retrograde Orbits Space Station
Authors: Zhang Yingyi , Zhang Wei
Published: August 2021

To improve the utilization rate of DRO, reduce the cost of human lunar and human mars exploration mission, and exploit space between earth and moon, this paper studied human lunar and mars exploration flight modes based on DRO space station. Firstly, the mission profile of human lunar and mars exploration flight mode based on DRO space station is analyzed by comparing with the direct round-trip lunar flight mode. The human lunar and mars exploration mission can be decoupled into the human space transportation mission and the lunar or mars landing mission by the DRO space station. Then, a flight mode evaluation model is established to analyze and evaluate quantitatively the advantages and disadvantages of the flight modes based on the DRO space station. The evaluation results show that the flight mode based on the DRO space station is a optimal flight mode.