bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of runner radial installation deviation on the flow characteristics of the 1000MW turbine
Authors: Wang Yifan , Huang Xingxing , Zhou Lingjiu
Published: June 2024

The flow simulation of a hydraulic turbine is not limited to calculations and analyses under ideal conditions and simplified models, but it should also consider the existence of radial installation deviations in actual operating conditions and their influence on the flow of the turbine. Therefore, this study focuses on a 1000MW unit and analyzes the internal flow characteristics under actual operating conditions while considering the radial installation deviations of the turbine wheel. The results show that the absolute value of pressure increases with the increase of radial deviation, but the difference value remains almost constant. And it also indicates that the magnitude of the radial forces increases with the increase in radial installation deviations. There are two linear relationship curves, one before 0.5mm and one after 0.5mm, with the latter growing at a faster rate. Furthermore, taking the crown as an example, the influence of the wall velocity-generated dynamic pressure on the clearance is different. Lastly, considering the magnitude of the combined forces and vibration amplitude, the crown is the most critical part that should be given attention. The research findings can guide the high-quality installation of 1000MW units during major overhauls and provide valuable technical references for similar units. The research outcomes can also guide the initial installation and major overhaul stages of 1000MW units and offer beneficial technical references for other similar units.
Research on Closing Law of Guide Vane in a Francis turbine during the Load Rejection Process
Authors: Wang Xiu , Yan Yan , Wang Wen-Quan
Published: June 2024

It has become a general trend for new energy to be connected to the power grid, and the tasks of peak and frequency regulation undertaken by hydropower units are tough. Inevitably, the Francis turbine operates under a transient process, which brings serious pressure fluctuations and instability problems. In the present study, a three-dimensional simulation of Francis turbines with the water pipeline system during the load rejection process is carried out. Results indicated that when a straight line is used to close guide vanes, the Francis turbine generates significant rotational speed, which poses a threat to system safety and stability. Based on this, the sinusoidal closing law proposed in the present study can effectively reduce the maximum rotational speed by 2.6%. After the end of load rejection, the difference in rotational speed between the two closing laws is 5.15%.
Analysis of the velocity non-uniformity in waterjet inlet duct
Authors: Shen Z H , Li W , Pan Z Y
Published: June 2024

Since the waterjet propulsion unique advantages, it’s applied more widely. But the Inlet duct and other structures prone to particular flows. Since the inlet duct of a special structure, the velocity distribution shows non-uniformity, departing from the waterjet pump design scenarios. In this paper, waterjet pump is simulated to study its velocity non-uniform of inlet duct and to investigate the discipline of the velocity distribution. By changing the inlet boundary conditions, the corresponding velocity field is obtained, to analyze the results under different conditions. It is researched the effect of inlet duct velocity non-uniformity on waterjet propulsion system.
Experimental study of the effects on performance of Francis turbine due to sediments in flow
Authors: Poudel Ravi , Shi Junde , Zhao Zilong , Qian Zhongdong , Guo Zhiwei , Chitrakar Sailesh , Thapa Bhola
Published: June 2024

The sediments in the flow cause deterioration of components of the hydraulic machinery and influence fundamental properties such as density and viscosity of the flowing fluid. Earlier researchers have demonstrated the influence of sediment-laden flow on the performance of pumps, but such investigations have not been performed for the Francis turbine. This research focused on the effects of sediment-laden flow on the performance of a Francis turbine. Hydropower Research Centre for Himalayan Region (HRCHR) had a laboratory facility especially designed to conduct tests on Francis Turbines with sediments in the flow. The test rig was a closed-loop type and had provisions for mixing sediments with water and maintaining a uniform sediment concentration throughout the circuit. The performance of a 2 kW Francis turbine was tested at three different GV (Guide Vane) angles for different load conditions with and without sediment in the flow. The results showed that there was no change in maximum efficiency in the case of a smaller GV opening, whereas the maximum efficiency in the case of sediment water was reduced for a larger GV opening. Meanwhile, Sediment particles did not affect the head under the same discharge, whereas output power decreased slightly for sediment-laden conditions.
Numerical analysis of the sand hydro-abrasion of a Pelton turbine injector
Authors: Quanwei Liang , Jie Liu , Yexiang Xiao , Yilin Zhu , Hengte Zhou , Haifeng Deng
Published: June 2024

Pelton turbines have great application prospects in the exploitation of high-head hydraulic resources. However, sediment abrasion within its components is the major challenge. In this paper, Euler-Lagrangian method is used to simulate the flow process of the sediment particles in Pelton turbines injector numerically. The hydraulic characteristics of the three-phase flow, the behaviour of the sediment particles and the abrasion distribution are also analysed in detail. Calculation result shows that the predicted motion characteristics of the particles are in good agreement with theoretical model, and the predicted abrasion distribution also matches well with the measured results.
Effectiveness of Air Admission through Short Pipes in Reducing Pressure Fluctuation of Propeller Hydro-turbine Flow Channel
Authors: Wu Huanyu , Luo Yongyao , Jin Faye , Zeng Chongji , Liu Xin
Published: June 2024

When the hydro-turbine operates under part-load conditions, a large-scale vortex flow will form in the draft tube. This vortex can cause low-frequency pressure pulsations that endanger the safe operation of the hydro-turbine. By injecting air into the draft tube, the structure of the vortex can be effectively disrupted, reducing the amplitude of the pressure pulsations. In this paper, a propeller hydro-turbine was studied, and the SST k-ω turbulence model based on the Reynolds averaged Navier-Stokes equations (RANS) was utilized to perform a full-channel unsteady numerical simulation on a part-load condition with the guide vane opening (GVO) of 35°. Then, the fast Fourier transform (FFT) was applied to analyze the pressure fluctuations at monitoring points on the draft tube wall, the head cover, and the nose of the spiral casing. The results indicated that injecting air with an appropriate flow rate into the draft tube through short pipes can reduce the pressure fluctuations on the draft tube wall by 51.4% to 72.5% and decrease the pressure fluctuations on the head cover and the nose of the spiral casing by approximately 40% to 42%. This study proposes a new air admission structure that can enhance the operating stability of the propeller hydro-turbine under part-load conditions.
Study on the Influence of Geometric Parameters on Vibration Characteristics of Hydraulic Oscillator Used in Oil Drilling
Authors: Tang Peng , Zhao Haoru , Zhu Baoshan , Lu Jiaxing , Zhang Wenwu
Published: June 2024

Hydraulic oscillator is an important drilling equipment extensively used in petroleum extraction and drilling work. It generates vibration along the axis direction to drive the drilling tool to drill and the drilling effect largely depends on the axial impulsive loading and frequency of the hydraulic oscillator. However, few present studies have been conducted on the influence of variations in key geometric parameters on axial impulsive loading and frequency of hydraulic oscillators, and systematic analysis is still lacking. Optimization calculations were carried out on throat inner diameter, throat length, nozzle spacing, and nozzle angle of the hydraulic oscillator. The analysis results show that: The overall impact of throat length and nozzle angle changes on axial load is small, while throat inner diameter has the greatest impact on the axial load. The axial load is 375.78 N when throat inner diameter is 10 mm, which is 8 times larger than that when throat inner diameter is 20 mm. Moreover, the throat inner diameter is smaller, both the axial load and amplitude are greater. Nozzle spacing has a significant influence on the axial load within a narrow spacing range. As nozzle spacing increases, the axial load increases overall while the amplitude shows a decreasing trend. Particularly, when nozzle spacing exceeds a certain value, the axial load does not vary significantly.
Effect of runner tip clearance on hydraulic performance of Kaplan turbine
Authors: Shui Biao , Liu Jue , Zhan Tingjun
Published: June 2024

Due to its structural characteristics, the Kaplan turbine has a specific tip clearance between blade and chamber of the runner. This paper simulates effect of varied runner tip clearance on hydraulic performance of Kaplan turbine by CFD, and model tests validated the results. The results show that the efficiency and cavitation level of turbine will decrease with the increase of runner tip clearance within a specific range.
Research on Automatic Testing of Pump Turbine Model Test Based on Intelligent Technology
Authors: Han Wenfu , Gui Zhonghua , Ni Jinbing , Man Zhe , Ding Jinghua , Li Dongkuo , Wang Gang
Published: June 2024

In order to test the performance of pump turbine, it is necessary to collect and analyze the performance indexes such as energy characteristics, stability performance, cavitation performance and force characteristics of the unit through the pump turbine model test test system. however, the current test systems all use manual operation based on the standard specification requirements to handle the data collection and analysis of the test, and the accuracy of the data relies on human experience and the efficiency is not high. The method described in this paper uses emerging computer test technology means such as big data technology, noise and image recognition technology to automatically and efficiently complete the test data test, and quickly complete the test test, while the test results are more accurate.
Research of Key Technologies on Design and Implementation of Intelligent Pump Station
Authors: Wang Xinxin , Zhao Zhe , Li Ying , Jiang Chunge , Li Ligang , Zhou Ye
Published: June 2024

With the continuous advancement of technology, intelligent solutions have found widespread applications in various fields, including pump stations in water management projects. This paper focuses on the key technologies involved in intelligent pump station monitoring, control, and operation. The paper takes a pump Station as an example and addresses the problems and current situation in its management. It designs the architecture of an intelligent pump station at three layers: business application, technical methods, and requirements. Solutions are proposed for pump station dispatch and operation, safety management, and engineering maintenance. Finally, by establishing a smart monitoring system based on the five senses and one brain concept and utilizing a dual-factor intelligent verification method in conjunction with digital twin technology. Finally, intelligent management of the pump station is achieved. By exploring these technologies, the paper aims to provide insights into the crucial aspects of designing and implementing intelligent pump stations, thereby facilitating more efficient and intelligent management, control, and operation of water management projects.
Flame detection method and application based on RGB-HSI model and initial flame growth characteristics
Authors: Zhou Yuquan , Liu Guanjie , Xie GuoDong
Published: June 2024

The safe and stable operation of hydraulic machinery equipment cannot be separated from various auxiliary electrical equipments and lubricating oils. And these are important factors in the occurrence of fire. Fire detection is used to detect fire hazards during the operation of hydraulic machinery equipment, which is of great significance to ensuring safety and stable operation of hydraulic machinery equipment and reducing economic losses. Traditional fire detection methods require the detector to be put close to the fire source, and the detector is also prone to interference, resulting in delayed detection, false alarm and missed alarm. To solve these problems, a flame detection method based on RGB-HSI model and initial flame growth characteristics is proposed in this paper. Firstly, after image processing such as binarization, filtering and dilation, the connected region of pixels is divided and the total amount of flame pixels is calculated. Finally, the region where the growth ratio of flame pixels exceeds the growth ratio threshold for three consecutive calculations is marked and alerted. The experiment proves that the real-time and accurate identification of the initial flame can be realized by combining the above image processing technology with the initial fire growth characteristics.
Energy storage peak-shaving demand prediction based on an improved neural network with hidden layers
Authors: Deng Dingshan
Published: June 2024

The result shows that the BP neural network has a very low convergent speed for load prediction, which leads to local optimization. This paper presents a modified GA for the optimization of the threshold value, the initial weight, and the addition of the smoothing coefficient. In addition, it improves the BP neural network’s adaptive learning speed and further improves the efficiency of the search. The proposed model is characterized by high convergent speed and global space retrieval capability. To validate the validity of the modified GA-BP model, the prediction of power load in some regions is made. Compared with the BP neural network forecast algorithm, this method has better performance in terms of prediction accuracy and takes less time in terms of prediction time than the BP neural network. In parallel, the realization of multiple sources of electricity from wind, solar, and heat storage is an important way to deal with large-scale new grid connections. Starting from an improvement in the efficiency of wind and PV generation, it is also possible to build a joint optimization scheduling model for wind, solar, and heat storage. The purpose of taking the minimum net load fluctuation is for optimization. Taking the typical output day of user scenarios as the optimization scenario, the scheduling strategies of wind power, PV, thermal units, and energy storage systems are introduced and simulated on the platform. It is proved that the proposed model can decrease the reduction ratio and the peak and valley load.
The technology of precise tapping of remaining oil during the high water cut stage of offshore multi-layer reservoirs driven by big data intelligence
Authors: Li Tingli , Yuan Zhiqian , Liu Chunyan
Published: June 2024

Based on traditional numerical simulation and optimization algorithm, combined with the “hard data” monitored by stratified injection and production real-time monitoring and automatic control technology, a fine reservoir model integrated reservoir knowledge and development law was established, and the remaining oil potential exploitation during high water cut stage was quantified and evaluated by deep forest method to adjust well productivity, greatly improving the remaining oil potential exploitation effect. The innovation has formed a set of accurate remaining oil potential tapping technology based on big data intelligent drive in offshore multi-layer reservoirs with high water cuts. This technology fully adopts the automatic and intelligent characteristics of data-driven and deep forest algorithms, and the historical fitting rate of production dynamic during the high water cut stage is more than 90%, which can accurately guide the design and implementation of the remaining oil potential tapping scheme and provide a reference for similar oil fields.
Capacity planning of household photovoltaic and energy storage systems based on distributed phase change heat storage
Authors: Shao Guangyi , Zhang Yanchi , Wu Hao , Wei Qing , Wu Qian
Published: June 2024

With the global energy reform, the energy storage field has become one of the current research hotspots. This paper considers the distributed phase change material unit (PCMU) system. First, the distributed PCMU model and the photovoltaic and energy storage systems model are constructed. Second, the actual capacity of the distributed PCMU that can participate in dispatching is analyzed. Finally, a calculation example is solved, and the optimal heat storage and electricity storage capacity is solved through the particle swarm algorithm. The results show that the constructed system has economic benefits.
Effect of fuel injection pressure on biodiesel blended combustion of Inland River diesel engine
Authors: Pu Xigang , Jiang Guohe
Published: June 2024

Compared with ordinary diesel, biodiesel has greater viscosity, density, and flash point, especially under medium and low load, which is easy to cause poor atomization and inadequate combustion. In this paper, an in-line six-cylinder inland river ship diesel engine was used as a model to conduct simulation tests under 50% load of propulsion characteristics to explore the effects of different fuel injection pressures on oil-gas mixing, combustion, and emission of fuel blended with a small percentage of biodiesel. The results show that the increase of fuel injection pressure can enhance the average turbulence intensity in the cylinder as well as increase the relative flow velocity between oil and gas, which is beneficial to the mixture combustion. High fuel injection pressure will promote flame propagation, increasing the maximum burst pressure and the average temperature in the cylinder. Compared to the fuel injection pressure of 24 MPa, NOx emission increases by 5.5% and 15.6% respectively at 27 MPa and 30 MPa, and decreases by 10% and 25% respectively by SOOT.
Methods of controlling fluid production from extracted layers of the same well injection-production in old oilfields
Authors: Dong Yuning
Published: June 2024

The implementation of the same well injection-production for old wells can reduce production costs, reduce the amount of surface-produced water treatment, improve the utilization rate of old wells, and further improve the water-driven recovery of oil wells. However, the difference in the physical properties of the reinjection section and the extraction section leads to an increase in the output of the extraction section and a limited amount of reinjection in the reinjection section. This results in an increase in the dynamic fluid level and the casing pressure at the wellhead, which not only has a greater impact on the same well injection-production tubing column but also poses a great safety hazard to the surface construction personnel. There is a great safety hazard for the construction personnel. Due to the limitation of the same well injection-production tubing column, it is impossible to use equipment such as a packer to limit the production volume of the recovered layer. The use of resin and cement to seal the tampering operation is not only expensive and risky, but also difficult to control the production volume of the recovered layer with a short period of validity. In order to achieve the effect of limiting the production of the extracted layer, the production of the extracted layer is controlled by reducing the number of re-shot holes after blocking the extracted layer by cementing operation. Therefore, it is necessary to optimize the shot hole parameters of re-shot holes after plugging the extraction wells in the same injection-production well using the finite element method. The results of the study show that the seepage resistance in the near-well zone is mainly affected by the number of shot holes and the depth of penetration of the shot hole apertures. In contrast, the diameter of the shot hole apertures, the density of the shot holes, the position of the shot holes, and the phase angle of the shot holes have little effect on the pressure in the near-well zone.
Design of corresponding fracturing parameters based on thin sand reservoir characteristics
Authors: Wei Guanglei
Published: June 2024

China’s onshore oil fields have entered the late stage of development, while the reserves of thin-poor layers account for a large proportion of the remaining recoverable reserves. The development of thin-poor reservoirs has become an important potential for tapping potential. In this paper, the numerical simulation method is used to optimize the crack radius corresponding to the fracturing of the thin-poll injection-production system. The optimization results show that the fractured radius of the well has a greater impact on the final cumulative oil production and recovery when the fractured radius does not break the permeability boundary for a thin reservoir with a fracture penetration ratio of water and oil wells between 35% and 45%. when the oil well is in the high permeability area and the water well is in the low permeability area, the fractured radius of the well and the surrounding area of the oil well are used. The situation has a greater impact on the final oil production.
Optimization of surfactant-enhanced injection parameters in Lamadian oilfield
Authors: Wang Hao
Published: June 2024

Optimizing injection fluid parameters is critical for the development of unconventional reservoirs since it is the principal strategy for increasing surfactant recovery in low-permeability reservoirs. This study used numerical simulation methods to objectively investigate the influencing variables under various injected surfactant values, based on the reservoir features of the target block. Additionally, it established the yield relationship corresponding to changes in reservoir pressure. Consequently, a correlation was established between the amount of injection, concentration of surfactant, distance between wells, extreme difference in permeability, and increase in pressure. This led to the determination of appropriate injection parameters for enhancing surfactant permeability. The study’s findings have practical implications for determining the appropriate injection scale of a reservoir surfactant system.
Design of positive pulse measurement while drilling system for mine rotary valve mud
Authors: Li Zongming , Pang Yanyan , Liu Ying , Ke Chen , Xudong Song , Zichen Liang
Published: June 2024

For the drilling of directional wells and horizontal wells, to ensure that the drilling trajectory is drilled in the coal seam in the direction designed before drilling, it is necessary to transmit information without interrupting the drilling process. The drilling fluid pressure pulse is divided into positive pulse, negative pulse, and continuous wave. The positive pulse transmission system with the mechanical structure of the lifting valve is widely used because of its high pulse signal strength and long propagation distance, which can be used in deep wells. With the increase of the information measured in the formation, the lifting valve can not meet the needs of the current information transmission due to the linear motion of the mechanical structure and the low transmission rate. The rotary valve as the pressure signal generation source can improve the pulse generation rate. Therefore, this paper analyzes the working principle and signal generation principle of the rotary valve positive pulse system, and collects the directional data and natural gamma value of the field test.
Long-term rolling prediction of transformer power load capacity based on the informer model
Authors: Yang Chuan , Shu Zhibing
Published: June 2024

There are currently no methods capable of long-term forecasting based on very long-term real-world data. Any false prediction may damage the electrical transformer. For this problem, a transformer power load based on the Informer model is used as a method of long-term rolling forecasting. This method uses the self-attention distillation mechanism in the Informer model to allow the decoder of each layer to shorten the length of the input sequence by half, thus greatly saving the encoder memory overhead, and this paper adds a rolling long-term prediction function, making the prediction decoding time extremely short. Taking the power load data of a certain province in China as a test case, the improved model Informer* was compared with the traditional Informer model. The results show that the prediction accuracy of the Informer* model is higher and the load prediction accuracy is effectively improved.
Research on Low Voltage Ride-through Characteristics of 300 MW VSPSH Based on BPA
Authors: Wang Yingwei , Wen Luo , Fan Yubin , Zhang Shunren , Zhang Guangqing , Gong Wenjun
Published: June 2024

With the development of new energy, the power grid scale is constantly expanding, which also brings new challenges to the stability of the grid. When some faults occur in the power grid, it leads to a voltage dip; if most of the devices are removed from the power system, it is easy to cause problems of stability and losses. Therefore, it is necessary to investigate the low voltage ride-through (LVRT) characteristics of power electronic equipment with large capacity before grid connection. Different from constant-speed pumped-storage hydropower plants (CSPSH), variable-speed pumped-storage hydropower (VSPSH) units have broad prospects for development in China due to their characteristics of frequency and voltage regulation, energy saving, and high efficiency. In this paper, the three-machine-nine-node model of 300 MW VSPSH is built based on BPA, and the large voltage dip caused by a three-phase short-circuit fault at the grid side is designed to test the LVRT capability of 300 MW doubly fed VSPSH.
Engineering optics and thermodynamics design of parabolic trough solar collector
Authors: Yin Hang , Sun Yujun , Zhang Ji , Che Sheng , Zhang Xiaolei , Xing Yuepeng
Published: June 2024

The development and design of parabolic trough solar thermal collectors (PTC) need to comprehensively consider the influence of optic, thermodynamic, layout, and other factors. The optics and thermodynamic analysis of PTC with different configurations was carried out, and the influence of layout on heat collection was studied. In the case of determined PTC aperture size, the distribution trend of solar irradiation flux density of different HCE diameters is the same, and the peak value of solar irradiation flux density is higher when the concentration ratio is larger. For the PTC with the same concentration ratio, with the incidence angle increase, the intercept rate and optical efficiency of the PTC decrease, the thermal energy loss rate increases, and the thermal efficiency decreases. Under the same incidence angle, with the increase of concentration ratio, the PTC’s intercept rate and optical efficiency decrease gradually, and the average efficiency of the PTC increases first and then decreases. In the process of PTC design and selection, considering the concentration ratio, latitude, and cost factors, the aperture size of 8.2 m and the HCE of the inner diameter of 90 mm can be used as the recommended configuration scheme for subsequent HCE development.
Thermal performance analysis of horseshoe crab shaped fin cold plate
Authors: Bai Yike , Yang Xinglin , Lu Lin
Published: June 2024

As we all know, efficient, safe, and stable operation of lithium-ion batteries is the key to ensuring vehicle performance. This type of battery can create a good amount of heat during the driving process of a car. Poor heat dissipation conditions accumulate heat, causing the battery to generate more heat, which leads to a very bad impact. More seriously, it can generate thermal runaway, seriously affecting the safe driving of the car. Therefore, designing an efficient heat dissipation structure is crucial for the safe use of batteries. This article focuses on the thermal performance analysis. In terms of heat dissipation structure design and optimization, a biomimetic horseshoe crab fin cooling plate structure is proposed. Finite element models of the module and cooling plate are established using Solidworks software, and CFD simulation is completed. Six cooling schemes under the flow direction of two cooling media are compared and analyzed with traditional rectangular fin cooling plates. The results showed that the cooling plate with horseshoe crab-shaped fins had better heat transfer performance, and the highest temperature of the battery module was lower.
Semi-submersible non-axial current generators based on improving current energy conversion efficiency
Authors: Wang Tian , Liu Yuhan , Li Mingxuan , Tang Jia , Li Wenbo
Published: June 2024

With the development and utilization of ocean current energy, how to improve the efficiency of ocean current energy utilization has become the focus of attention in many countries. In this paper, the optimal design of the structure of the ocean current generator is mainly used to improve the energy capture power and the conversion efficiency of the ocean current energy unit under the condition of low flow rate. The effect of peripheral fluid growth on the generator is analyzed using finite element analysis. The three-dimensional finite element model of the semi-submersible axial-current generator is established by using the ANSYS finite element method, and the calculation and analysis of the peripheral fairing are simplified. Through finite element calculation and analysis, the velocity cloud diagram and velocity linear vector diagram are obtained, respectively. The results show that the semi-submersible axial current generator has the ability to start and generate electricity at low velocity and can use the current resources for power supply in situ. Its application can maximize the current capture and greatly improve the utilization rate of current energy.
Icing characteristics of the superhydrophobic surface of gas turbine fairing
Authors: Wang Yanhua , Chen Haoran , Hu Zhanwei , Wang Zhongyi , Wang Meng
Published: June 2024

In order to investigate the mechanism underlying the impact of superhydrophobic surfaces on the icing and anti-icing characteristics of fairings, this study focuses on marine gas turbine fairings as the research subject and employs numerical simulation methods to examine how droplet diameter and impact velocity influence the icing characteristics of superhydrophobic surfaces on fairings. The findings reveal that larger droplet radii are more prone to freezing onto superhydrophobic surfaces, resulting in a more stable ice sheet formation. Moreover, higher droplet velocities facilitate easier freezing on superhydrophobic surfaces, leading to larger frozen areas, thicker ice sheets, and more pronounced ice peaks. Additionally, differences in impact angles prevent droplets from freezing.
A false trigger pulse elimination circuit for low-frequency energy harvesting active rectifiers
Authors: Zeng Ziyi , Li Chunlong , Huang Hui , Wu Jianhui , Liu Wentao , Wang Zhen
Published: June 2024

In this article, a false trigger pulse elimination circuit is proposed to be used for a low-frequency energy harvesting active rectifier. It is divided into two-stage circuits, each stage almost including a switching signal generation circuit, a switching inverter, and an inverter to eliminate false triggering pulses on the rising edge and falling edge respectively. There is an edge detection circuit in each switching signal generation circuit, generating a switching signal that controls the switching inverter’s on-off behavior. This allows the inverter to achieve inverter output voltage clamping by turning off its inverter function and turning it into a switch that is only turned on at the high or low level. At the same time, a thyristor delay element is used to determine and adjust the effective level time of the switching signal, which can reach over 150 μs, completely covering the rising or falling edge false trigger pulse so that no GΩ-level resistors are needed in the low-frequency field. The results show that the low-frequency false trigger pulse elimination circuit proposed in this article can better eliminate false trigger pulses on both rising and falling edges. It can also achieve on-chip integration, reduce the power consumption of the self-adaptive delay compensation loop, and enhance the stability of the circuit.
Energy scheduling method for island micro-grid system based on prediction model
Authors: Du Xiaoting
Published: June 2024

Renewable energy, due to its characteristics such as volatility and intermittency, brings difficulties to the energy scheduling of renewable energy power generation systems. The main way of island power generation is to use renewable energy power generation. This chapter proposes a hierarchical energy scheduling method based on the prediction model through the research on the energy scheduling method of the island microgrid system to realize the energy optimization between the microgrid sub-systems, to achieve the maximum consumption of renewable energy for power supply, and to reduce the power supply cost and improve user satisfaction. The effectiveness of this method in improving the energy supply-demand balance of the microgrid sub-systems is verified through experiments.
The command allocation of the combined fire and storage FM system considering the benefit optimization
Authors: Cheng Liwei , Hao Yongsheng
Published: June 2024

The proportion of new energy generation connected to the grid is increasing year by year, which brings challenges to the frequency stability of the power grid. More controllable thermal power units are gradually retrofitted with energy storage batteries for joint frequency regulation, which can better suppress the fluctuation of grid frequency. In this paper, the comprehensive benefit model of a fire-storage joint FM system is constructed, which contains FM cost and FM benefit. The optimized power value of fire-storage joint FM is calculated based on the optimization of historical data of FM command, and finally, the simulation is compared with the constant rate response strategy. The results show that the strategy of this paper increases the comprehensive benefit of fire-storage joint FM systems by 1.71%.
Optimal scheduling of energy routers based on distributed CAES systems
Authors: Xie Yuguang , Ma Wei , Zheng Tianwen , Li Jinzhong , Zhang Hong , Xu Bin
Published: June 2024

With the rise of renewable energy, distributed energy, and other different forms of energy, the architecture and function of the energy router are relatively perfect, for the topology of the energy router itself, different forms of energy in the energy router flow, conversion to realize the large-scale use of distributed energy equipment has also gradually become a hot spot of research. However, there are fewer studies on the energy router with a distributed CAES system to participate in the optimal scheduling of energy for integrated energy systems. Therefore, this paper is based on the operational domain model of an energy router with a distributed CAES system and analyzes the physical characteristics and coupling relationship of non-energy storage components, takes air pressure, temperature, and oil volume as state variables, takes charging, power generation, and heating power as external interfaces, and utilizes internal interface variables such as air quality and flow rate to realize energy storage, flow, and other internal interface variables to realize the communication between energy storage and non-energy storage elements, and finally determine the operation domain of the system. Secondly, the feasible domain of the energy router based on the distributed CAES system is portrayed, and the optimization of the system parameters is guided with the help of the relative distance by establishing the electric and thermal power constraints and the storage state constraints. Finally, the effectiveness of the feasible domain analysis method in the energy router of a distributed CAES system is verified by taking a northern region as an example.
Energy storage capacity optimization of optical storage microgrid considering customer satisfaction and depth of energy storage discharge
Authors: He Qianshuai , Zhou Renjun , Li Bicheng , Yue Qi
Published: June 2024

The influence of the depth of battery discharge (DOD) and user satisfaction on the capacity configuration of the optical storage microgrid cannot be ignored. In this paper, the minimum comprehensive cost of an optical storage microgrid is taken as the objective function, and the model is established by considering the SOC after DOD, user satisfaction with electricity consumption, power balance, and other constraints. The numerical examples show that the proposed method can allocate suitable energy storage capacity for optical microgrids and ensure user satisfaction.
Photovoltaic grid-connected monitoring technology considering power quality
Authors: Yao Qiang , Liu Yongmei , Song Xiaozhe , Hu Lijuan , Zheng Qiangren , Liu Jun , Zhang Xiaohua
Published: June 2024

With the continuous expansion of grid-connected photovoltaic power generation, monitoring the power quality fluctuations in intelligent photovoltaic grid-connected systems has become a key research direction. Addressing the issues of low accuracy in voltage and current monitoring, as well as insufficient monitoring of SOE events, a comprehensive power quality-oriented detection technology for photovoltaic grid integration is proposed. This technology enables automatic monitoring of power quality fluctuations by collecting signals such as voltage deviation and frequency deviation. The study compares techniques involving a determination of input voltage and current amplitudes, power, phase difference, and SOE event design. The results demonstrate that the power quality monitoring technology for photovoltaic grid integration proposed in this study exhibits high accuracy in monitoring the imbalance of three-phase voltage and current.
Electromagnetic transient simulation of power system based on PSCAD calling ADPSS
Authors: Chen Deyang , Miao Lu , Wang Feng , Mu Qing , Gao Minli
Published: June 2024

As the power system gradually expands into a massive scale, time-varying complex system, the requirements for simulation analysis software are constantly improving, and electromagnetic transient analysis plays a crucial role in the power system. Therefore, to solve the possible limitations of this traditional simulation method, this paper proposes an electromagnetic transient simulation of power systems using PSCAD, called ADPSS. Firstly, according to the basic overview and advantages of the electromagnetic transient analysis program PSCAD/EMTDC and the mathematical model software package ADPSS, the interconnection principle and implementation method between PSCAD/EMTDC and ADPSS are studied, and a simple power system power supply model is established in PSCAD. Then, the principle of PSCAD-ADPSS interface technology is studied. The electromagnetic transient simulation is carried out in the interface environment, and the interface custom components are designed. Finally, by conducting a comparative analysis of the simulation outcomes, it is found that the simulation waveforms obtained in the two simulation environments are almost the same, which shows the effectiveness of PSCAD-ADPSS interface simulation technology in electromagnetic transient analysis and has the potential to enhance the precision and dependability of electromagnetic transient simulation.
A resilience evaluation index system and evaluation method for regional distribution networks facing typhoon disasters
Authors: Zhang Yi , Wang Dengzheng , Xu Qing , Li Qingxi , Liu Zhongjian , Jiang Shigong , Zhao Dong
Published: June 2024

The occurrence of natural climate disasters such as typhoons may lead to large-scale power outages in the distribution network, and a quantitative assessment of the resilience of the power grid is a key step in preventing and resisting the harm caused by natural disasters to the power grid. This article establishes a regional distribution network resilience evaluation index system for typhoon disasters from the perspectives of reliability, safety, and economic resilience of the power grid after a typhoon occurs. Based on the above indicator system, the fuzzy comprehensive evaluation technology is adopted to evaluate the resilience level of the power grid under typhoon disasters. Taking a regional distribution network in Guangzhou, China, as an example, a numerical analysis was conducted, and the results showed that the proposed resilience evaluation indicators and methods can reasonably and quantitatively evaluate the resilience level of urban distribution networks under typhoon disasters.
A study on the resource scheduling strategy in substations with high penetration of photovoltaic electricity
Authors: Zhan Juchao , Du Jiao , Zhang Haichuan
Published: June 2024

In 2020, China introduced the strategic objectives of reaching the peak of carbon emissions and achieving carbon neutrality. However, due to the limited self-regulation capabilities of the power grid and increasingly prominent issues such as insufficient consumption of photovoltaic electricity generation, there are challenges. Therefore, in this paper, a coordinated interaction model of source-load-storage is established with the aim of optimizing the on-site utilization of photovoltaic electricity. Rolling scheduling of substation resources is conducted at three temporal scales: pre-scheduled, interim, and actual-time, and the effectiveness of the proposed approach is verified using actual case studies. The data suggests that compared with single-time-scale scheduling schemes, the on-site consumption rate of photovoltaic electricity increases by 0.32% in the case study substations, validating that the scheduling approach can improve the photovoltaic electricity consumption rate in the substations.
State of charge estimation for lithium batteries based on multi-timescale FFRLS-UKF
Authors: Wei Ying
Published: June 2024

State of charge (SOC) can represent the remaining battery capacity, and accurately estimating SOC is very useful for the drivers of electric vehicles. This study proposes a lithium battery SOC estimation technique based on multi-timescale forgetting factor recursive least squares as well as an unscented Kalman filter (MTS-FFRLS-UKF). The MTS-FFRLS-UKF uses a circuit with a 2-RC network as the battery model, whose parameters are continuously updated at a timescale that is different from SOC estimation. The experimental results under a dynamic test prove the availability and accuracy of MTS-FFRLS-UKF. Continuous parameter update enhances the accuracy of battery modelling and furthermore the SOC estimation accuracy. The mean absolute error (MAE) and root-mean square error (RMSE) of SOC estimation decrease to 0.58% and 0.62%, respectively.
Wind power prediction based on NGO-LSTM
Authors: Chen Panlei , Li Jianguo
Published: June 2024

At present, wind energy is mainly utilized through wind power grid connections. However, because of the uncertainty of wind energy, the grid connection will inevitably have an impact on the system. In order to adjust the grid dispatching plan in real time and improve the grid’s capacity to absorb wind power, a short-term wind speed prediction method based on NGO-LSTM was proposed. Taking the measured data of wind farms as an example, the prediction accuracy of the proposed method is compared with that of existing algorithms. Experimental results show that the R2 of the NGO-LSTM coupling model is closest to 1, and the RMSE, MAE, and MAPE are all smaller than the other two models, verifying the effectiveness and advanced nature of the proposed method.
The wind turbine nacelle oil-level detection algorithm based on improved YOLOv5n-Seg
Authors: Zhao Yong , Hu Chunsheng , Li Hao , Mu Guojun
Published: June 2024

To enable the detection of oil-level information within the oil pot in wind turbine nacelles by inspection robots and address the issues of large model parameters and slow inference speed in the original YOLOv5n-Seg model, this study improved the Backbone and Neck of the YOLOv5n-Seg model using the improved RepVGG module and depthwise separable convolution, respectively. It reduced the number of output channels of each layer network in the improved YOLOv5n-Seg model’s Backbone and Neck to half of its original size. Compared to the original YOLOv5n-Seg model, the improved YOLOv5n-Seg model has significantly optimized parameters and inference speed. These improvements are of significant importance for enhancing the operational efficiency of inspection robots. Additionally, the study designed an oil-level detection algorithm based on the improved YOLOv5n-Seg model. The error between the oil level information detected by the algorithm and the manually detected oil level information does not exceed 7%, which can effectively replace manual oil level detection.
The application of state feedback principle in turbine adjustment system with Python control library
Authors: Gong Chongquan
Published: June 2024

This study investigates the utilization of the Python-Control library in contemporary control theory. The Python-Control package, comprising a collection of Python classes and functions, facilitates the comprehensive analysis and design of feedback control systems. Pole placement, a widely utilized method in the automatic control domain for control system design, is particularly emphasized. This paper explores the application of Python-Control in pole assignment, aiming to enhance control system performance. Additionally, the pole assignment method is successfully implemented in a hydro governor model, demonstrating the efficacy of the Python-Control library in practical control system applications.
Dam control system based on DDPG algorithm
Authors: Zhang Zifei , Liu Lei , Wang Zichun
Published: June 2024

Dams, regarded as a form of hydraulic engineering, are purposed to intercept river or canal flow to either elevate water levels or regulate discharge rates. The discharge of a dam is subject to influence by various factors, including precipitation, temperature, and regulatory policies. Nevertheless, in real-world scenarios, the precise value of the expected dam flow rate is challenging to ascertain through simple arithmetic operations. In this study, a novel dam flow model has been formulated. Through the utilization of the DDPG algorithm and deep learning techniques applied to data from the current month, the parameters of the dam control differential equations have been determined, and the transfer function after Laplace transformation has been established. Consequently, only the current month’s fluctuations in the water level of Lake Huron need to be determined to derive the corresponding dam flow rate for that month.
Study on kinetics of biomass energy conversion and utilization between wheat straw and rice husk
Authors: Ao Hu , Xie Haiwei , Zhang Tianle , Guo Jiaming
Published: June 2024

The environmental problems caused by fossil energy make people pay more and more attention to biomass energy, and pyrolytic biomass has great potential. To make the conversion and utilization of biomass energy more effective, the principle of pyrolysis between different biomass was studied. This study conducted co-pyrolysis of rice husk (DK) and wheat straw (MG) under different mixing ratios (DK: MG= 1:1, DK: MG= 2:1, DK: MG= 1:2, DK: MG= 3:1, DK: MG= 1:3). Based on TG and DTG, the temperature characteristic value and the weightlessness rate are analyzed, and the activation energy (E) was using the FWO method. The results showed that the trend of different blending ratios of biomass pyrolysis are the same, and can be divided into three stages. With the addition of MG, the two biomass react more fully during pyrolysis. When DK:MG=1: 3, the weight loss rate is as high as 98.26%, and the peak temperature Tmax is 317.4°C. Under these conditions, the synergistic effect between the two biomass is more obvious, and the difference between the actual activation energy and the theoretical activation energy is the largest, up to 5.6 kJ/mol.