bluuebunny/crossref_metadata_2025 huggingface dataset:
Parameters identification and application of composite plate reinforcement mesh based on DXF data
Authors: Yin Haibin , Cai Zhixiang , Zhou Zepeng , Shi Dongxing , Yu Jiajun , Li Zhongwei
Published: June 2024

This paper presents an algorithm for identifying the process parameters of a laminated plate reinforcement mesh. To accommodate the actual production needs, the computer software of the production line is employed for the identification of parameters and data processing of the DXF steel mesh file. In this context, a C++ programming algorithm is utilized for the identification of the parameters of the imported DXF file, as per the production line’s processing requirements. DXF is an AutoCAD vector graphics exchange file that is available in two storage formats: ASCII format and binary format. The ASCII format is easily readable and therefore, DXF is widely used, with most CAD software capable of reading or outputting DXF files. This paper initially scrutinizes the structural attributes of DXF files, normalizes the design standard of graphics files, and then reads the coordinates of each point of the POLYLINE entity. A parameter identification algorithm is devised to address the issue of steel bar bending in drawings, with the program designed to verify its accuracy.
A comprehensive study on the romax-based comprehensive shaping method for skewed cylindrical gears
Authors: Ma Jingyu , Wang Shufen
Published: June 2024

Tooth profile modification is one of the effective ways to solve the vibration and noise problems in gear transmission. This article is based on the dynamic Romax Designer software for simulation and studies the micro modification problem of helical cylindrical gears in a certain reducer. Based on the analysis of the limitations of tooth profile modification and tooth orientation modification methods, a comprehensive tooth profile modification method is proposed. The simulation results show that the transmission error, load distribution, meshing situation, and service life of the gear have improved after adopting the comprehensive modification method, thereby improving the transmission accuracy, reliability, and durability of the gear. This method can provide reference and reference for gear modification of reducers.
Research on the scheduling of steel mesh production line based on the improved grey wolf algorithm
Authors: Yin Haibin , Feng Yu , Xie Junyong , Zhou Xiangqun , Zhang Yushun , Shi Dongxing , Li Zhongwei
Published: June 2024

To solve the scheduling problem of a flexible production line of reinforced mesh, a mathematical model of flexible production line scheduling of reinforced mesh was established to minimize the maximum completion time. The Improved Gray Wolf Algorithm (IGWO) was designed, and the improvement measures of the Gray Wolf Algorithm (GWO) were proposed from the population initialization method, key parameter improvement, and search mechanism. Through the example verification, the Improved Grey Wolf Algorithm is applied to the scheduling problem of the flexible steel production line. The problem of the flexible production line of steel mesh and the results of the Improved Grey Wolf Algorithm, Grey Wolf Algorithm, Genetic Algorithm (GA), and artificial scheduling are compared. The results verify that the results of the enhanced Grey Wolf Algorithm have better quality and can better guide the production line to carry out efficient and energy-saving production.
Research on optimal dispatch of 5G base station VPP with standby energy storage
Authors: Chen Tongxuan , Zhang Zaiyi , Ma Xiufan
Published: June 2024

With the rapid increase in the construction of 5G base stations, the backup battery of 5G base stations will be a huge potential energy storage resource. China’s electricity market reform is constantly advancing, and the study of 5G base stations’ standby energy storage to participate in power optimization dispatch is an effective way to realize the reciprocal benefits of power grids and telecommunication operators. Considering the special characteristics of 5G base station backup energy storage to participate in the power market, the article establishes a virtual power plant of 5G base station considering the backup energy storage. Then, the 5G base station VPP is added to the operation of the power grid as an adjustable resource, and the dual-5G base station VPP optimization matrix is built. Finally, a numerical example verifies that the standby energy storage of the 5G base station contains rich schedulable capacity and that the 5G base station VPP can validly improve the economy of power grid operation.
Research on coordinated control technology of hybrid energy storage under grid-connected/off-grid dual mode
Authors: Sun Rui , Gu Cailian , Xue Shuai , Cai Chaohao
Published: June 2024

Aiming at the multi-time scale intermittency of renewable energy in microgrids and frequent power fluctuations will lead to a series of power quality issues. So, it is necessary to propose appropriate strategies for controlling the energy storage systems of microgrids to ensure energy balance. In microgrids, two types of battery energy storage are used to form a hybrid energy storage system, namely, zinc-bromine flow battery for energy storage and lithium titanate battery for energy storage. By analyzing the functionality of various energy storage systems in the grid-connected/off-grid dual style, the operation objectives of the hybrid energy storage system in different modes are proposed. In the meantime, the control strategy is formulated by combining the smoothing fluctuation characteristics of power-type energy storage and the peak load shifting features of energy-type energy storage. Finally, the efficiency of the hybrid energy system control strategy is checked by the simulation software in the connected/off-the-grid mode.
Resilience-oriented critical load restoration for railway distribution systems in remote areas by coordination of photovoltaics and energy storage systems
Authors: Wang Ying , Liu Weizhi , Ma Yingtao
Published: June 2024

The utility power infrastructure is relatively weak and susceptible to extreme conditions in remote areas, so the resilience enhancement of the railway distribution system is essential to ensure the service to critical loads, such as communication and signal devices, to prevent undesirable crash events. After extreme events, distributed resources such as distributed photovoltaics (PVs) and energy storage systems (ESSs) can be coordinated to restore critical loads as soon as possible. In this paper, a critical load restoration method for railway distribution systems in remote areas is proposed. The PVs and ESSs are coordinated to restore the critical loads distributed along the railway line. The problem is formulated as a mixed integer linear program and solved by off-the-shelf solvers. Finally, the effectiveness of the method is validated through a real-world case in China.
A comprehensive energy flow analysis method based on hydrogen energy to electric energy conversion
Authors: Bian Jiayu , Zhou Zhuan , Yu Jin , Shi Xiaochao , Huang Ping , Du Wenzhe
Published: June 2024

With increasing global concerns about climate change, more and more countries and regions are turning to sustainable energy, and hydrogen energy, as one of the representatives of clean energy, is gradually becoming one of the key areas for development in various countries. Due to its high energy density, easy storage, and pollution-free characteristics, hydrogen energy has been widely used in fields such as automobiles, aviation, and petrochemicals. In the automotive industry, hydrogen energy, as a renewable and clean energy source, has become one of the development directions. Compared to traditional fuel, hydrogen-powered vehicles not only achieve zero emissions but also have higher energy efficiency and can achieve longer range. Currently, multiple countries around the world are accelerating the promotion of hydrogen-powered vehicles and building related infrastructure such as hydrogen refueling stations. In the aviation field, hydrogen energy also has broad application prospects. Traditional aviation fuel contains a lot of hydrocarbons, so the pollution problem of the aviation industry has been a concern. As a clean and renewable energy source, hydrogen energy not only solves the pollution problem in the aviation industry but also has a very high energy density, providing sufficient power to support aircraft flight. In addition to the automotive and aviation fields, hydrogen energy can also be widely used in the petrochemical industry. Currently, traditional petrochemical production processes emit many harmful substances such as carbon dioxide, greatly affecting environmental quality. By using hydrogen energy, harmful substances such as carbon dioxide generated in traditional petrochemical processes can be converted into renewable resources, thus achieving an environmentally friendly, efficient, and sustainable production model.
Multi-objective optimization of an integrated energy system based on enhanced NSGA-II
Authors: Zhao Ziyi , Xiao Xiang , Yang Wentao , Yin Shiwen , Ding Xiangri , Gao Haixiang , Gao Yusong
Published: June 2024

To solve the energy crisis, China has made great efforts to develop an integrated energy system to achieve multi-energy coordination, mutual aid, energy conservation, and carbon reduction. This article mainly studies the multi-objective optimization scheduling problem of a combined cooling, heating, and power system considering wind and solar energy storage. Firstly, from two different perspectives of economy and carbon emissions, an economic objective function and an environmental objective function are established, and a multi-objective optimization configuration model and corresponding constraint conditions for the combined cooling, heating, and power system considering wind and solar energy storage are constructed. Then, an enhanced non-dominated sorting genetic algorithm II (NSGA-II) is proposed, which enhances the efficiency and accuracy of the algorithm by introducing dominance strength and variance factors. Finally, a simulation analysis was conducted on a running cogeneration system in a certain area of western Liaoning to attest to the validity of the model and method proposed in this paper.
Optimization of solar-air source heat pump hybrid heating system
Authors: Zhang Yuxin , Tang Xiaoping , Ji Dongmei
Published: June 2024

In order to construct a versatile, complementary, low-carbon, clean, and efficient heating system, this study explores the potential of a solar-air source heat pump (SAHP) hybrid heating system. A simulation model is established in TRNSYS, and the particle swarm algorithm (PSO) and genetic algorithm (GA) from GENOPT and MATLAB are employed. With the aim of minimizing the annual cost, optimization is conducted on the key parameters and operational strategies of the system. Comparative analysis between the two algorithms reveals that PSO slightly outperforms in cost reduction, while GA exhibits a slight advantage in enhancing system performance. Significantly improved energy savings are achieved by appropriately reducing the rated heating capacity of the air source heat pump and increasing the volume of the water tank.
Thermal analysis of a gas-liquid compressed carbon dioxide energy storage system
Authors: Yu Zhenyue , Li Jiantao , Su Wei , Xu Cheng
Published: June 2024

In recent years, compressed CO2 energy storage (CCES) systems have attracted increasing attention, because the high-pressure storage tanks in the CCES systems are relatively small, thereby reducing investment costs and improving geographic construction flexibility. In this paper, we propose a gas-liquid CCES system that has strong industrial feasibility. A comprehensive thermodynamic evaluation and parametric analysis were performed for this system. The results show that the efficiency is 72.99% and the storage pressure is an important parameter influencing the thermal performance of this system, and the reasons behind it are explored.
An enhanced strategy for new energy generation black-start based on hybrid energy storage system
Authors: Song Zhen , Wang Hongtao , Wang Haobo , Xin Peiqi
Published: June 2024

In the past few years, the connection of extensive power grids with a substantial influx of renewable energy has resulted in a growing hazard of significant power failures. Conventional black-start systems are inadequate in promptly and adaptively recuperating from such outages. Consequently, the emergence of new energy generation integrated with energy storage technology to deliver black-start services has become a prevailing trajectory. In this research article, hybrid energy storage is implemented for the wind and solar power generation system to address the issue of inadequate inertia support capacity during the black-start process. The system incorporates a virtual synchronizer to manage and replicate its inertia and damping features, thereby enhancing the black-start capability of renewable energy generation. The effectiveness of the proposed strategy is verified through simulation in Matlab/Simulink.
Research on robust optimization of the integrated energy system in industrial parks based on adaptive genetic algorithm
Authors: Jia Xiaoqiang , Yang Yongbiao , Du Jiao , Gan Haiqin
Published: June 2024

As the core energy supply mode of the future park, the operation strategy will have an enormous impact on the operating cost and energy efficiency of the park. To further enhance the economic and robustness of the park’s integrated energy system (IES), an optimization model for the operation is established based on robust algorithms and adaptive genetic algorithms (GA). The results show that the optimized carbon neutral park’s comprehensive energy system achieves full consumption of renewable energy, and the utilization rate of new energy reaches 100%. Cool storage is used when the energy price is low, on the contrary, cooling is supplied. After considering the consumption indicators of new energy, the improvement of the new energy utilization rate can raise the system’s efficiency.
Risk assessment of the high percentage of distributed renewable energy access to the grid
Authors: Zhang Jianing , Zhang Xin , Cao Xiangyang , Bo Qibin , Wei Jia , Yu Shunxiang
Published: June 2024

Randomness and uncertainty are the outstanding characteristics of renewable energy, and the extremely high proportion of distributed renewable energy connected to the grid is bound to cause a serious impact. To comprehensively consider the uncertainty of renewable energy, the probability density function of distributed new energy is used to represent its output level. In addition, due to the geographical proximity of distributed new energy sources, there is a correlation between the output of distributed renewable energy sources. The copula function is used to denote the relation between their generation. Then, the method is verified by the IEEE 34-bus system.
An optimal configuration method of energy storage system considering source-load matching
Authors: Jiang Ruofei , Liu Hongwei , Peng Haojie
Published: June 2024

With the introduction of the dual-carbon goals, renewable energy sources have experienced rapid growth. However, due to the intermittent, stochastic, and fluctuating nature of renewable energy, a high penetration of these renewable energy sources poses significant challenges to grid stability. To address this issue, this paper presents an optimization configuration method for the energy storage system (ESS) that considers source-load matching. Firstly, the evaluation index of source-charge matching and the economic index of energy storage system are put forward. Then, an energy storage optimization configuration model considering source-load matching is established. The optimization objective of this model is to minimize the daily average comprehensive cost of energy storage and the penalty cost of source-load matching deviation. Finally, the Gurobi solver is invoked on Matlab platform for simulation analysis, and the results show that the energy storage optimization configuration model proposed in this paper can effectively improve the source-load matching.
A comprehensive power quality assessment method based on data envelopment analysis method and mutation decision-making
Authors: Zhou Hangyu , Li Sicheng , Ma Xiufan
Published: June 2024

As the construction of new power systems continues to advance, integrating a high percentage of new energy sources into the grid and the massive application of power electronic equipment brings serious power quality problems. At the same time, power quality assessment is the basis for solving power quality problems. A comprehensive power quality assessment method combining data envelopment analysis and mutation decision-making is proposed in this paper. Firstly, a power quality governance efficiency model using data envelopment analysis is constructed. Secondly, a power quality assessment method is proposed, combining governance results and mutation decision-making. Finally, the efficiency value and power quality value of each assessment point are obtained to realize the governance efficiency and power quality ranking of the assessment points. The example results prove the effectiveness of the proposed method.
Grid dispatching model and benefit analysis of concentrating solar power plants considering flexibility
Authors: Li Kefei , Wang Xiuli , Xiao Yunpeng , Li Bo , Deng Zheng
Published: June 2024

With the increasing penetration rate of renewable energy with volatility and uncertainty, flexibility has become an important factor to consider in the operation of the power system. To study the grid-connected dispatching and benefit analysis of CSP plants considering flexible supply-demand balance in the electricity market, the output level of CSP is modeled according to the internal steady state energy flow relationship. Secondly, we model the supply-demand characteristics of flexible resources. Finally, we establish an optimization dispatching model that considers the penalty of insufficient flexibility. The calculation example verifies the effectiveness of considering flexibility supply-demand balance and CSP plants in improving system flexibility.
A method of voltage sag detection based on strong tracking SVD-UKF
Authors: Yang Tao , Du Hongmiao , Li Haibo , Zhang Anbin , Zhang Shuangxi
Published: June 2024

Addressing issues of the traditional strong tracking unscented Kalman filtering (STUKF) algorithm in the process of voltage sag detection, such as inadequate precision, large computational complexity, and unstable iterative procedures, a method of voltage sag detection based on strong tracking SVD-UKF is proposed. Only one unscented transformation (UT) is used per iteration by establishing the linear state equation based on the voltage signal model, which simplifies the calculation procedure. Substituting singular value decomposition (SVD) for Cholesky decomposition averts the challenge of non-positive-definite error covariance matrix, ensuring stable execution of the algorithm. The action position of the fading factor is improved to further enhance detection precision. Through simulation experiments, we validate that the proposed method could effectively detect voltage sag characteristics, including amplitude, phase, and duration time.
Robust optimal dispatching of power grid with the participation of virtual power plants
Authors: Bo Qibin , Zhang Xin , Cao Xiangyang , Zhang Jianing , Qiu Xuanyu , Wu Yifan
Published: June 2024

One of the key technologies for creating intelligent distribution networks is energy management systems, which allow virtual power plants (VPPs) to combine distributed flexible resources and accomplish unified scheduling and coordination. This paper presents a solid optimization model that compromises safety and economics for distribution networks involving virtual power plants. First, a power flow model for the distribution network is created to minimize voltage variation, operating cycle cost, and the safety operation of several AM (active management) methods as constraints. Second, a strong optimization model for the distribution network was built with the participation of virtual power plants, accounting for the unpredictability of the load and fresh energy. Finally, the problem was solved using the relaxation evolution technique, and the precision and potency of the suggested model were shown by doing a simulated comparison study on the upgraded IEEE33 node testing system.
Study on fast transient overvoltage characteristics of substation under UHV disconnector operation
Authors: Qu Zheyi , Wang Haibo , Zhou Wenjie , Chen Mingliang
Published: June 2024

Due to the short duration of fast transient overvoltage in the substation, the suppression effect under the control strategy of traditional optimization equipment and switches is not good. Therefore, the characteristics of fast transient overvoltage in substation under the operation of a UHV disconnector are proposed. The fast transient condition of the substation is analyzed, the corresponding simulation method is set, and it is simulated. The elimination operation is carried out by using the reverse sequence backtracking formula, and the relevant parameters of the fast transient condition simulation of the substation are obtained. The inductance of the substation is calculated in the fast transient process, the potential in the equivalent circuit is obtained by using the capacitance and inductance, and the reactive power compensation capacity on the electromagnetic transient model of the fast transient process is comprehensively considered, so as to calculate the rapid transient overvoltage of the substation and realize the research on overvoltage characteristics. The method in this paper can ensure the rapid transient overvoltage level decline, successfully realize the automatic voltage regulation, effectively maintain the stability of voltage, and effectively restrain overvoltage to keep it within an acceptable range.
Operation flexibility analysis of a 600 MW coal-fired power plant incorporating the CO2 capture unit
Authors: Dong Wei , Si Paiyou , Ma Yunteng
Published: June 2024

To obtain the impact of CO2 capture in a coal-fired power plant on the operation flexibility of the plant, a 600 MW sub-critical power plant was selected as the case, and sensitive analysis of different operation parameters was carried out to obtain the operation characteristics of the plant under various operating conditions. The results show that the operation flexibility of the coal-fired power plant with a 90% CO2 capture ratio will be reduced by 23.73% and the impact on the operation flexibility of the plant will gradually increase with the increase in the size of the plant, and the use of advanced low-energy solvents can reduce the impact of CO2 capture on the operation flexibility of the power plant.
Microgrid based on ICA and improved cuckoo search algorithm optimizing scheduling methods
Authors: Yang Huixuan , Xia Qianqian , Su Ming , Yan Bo , Zhang Ruizhao , Liu Jinhui
Published: June 2024

The optimal operation of microgrids can provide a strong guarantee for the efficient utilization of distributed power and renewable energy. To solve the important problem of optimized operation of microgrids with a large proportion of distributed power sources, a microgrid optimal scheduling and operation method is proposed in the paper. This method first establishes a microgrid model containing distributed power sources and uses the ICA algorithm to screen out the key factors in the economy of the grid system. Then, taking the construction and operation cost of the microgrid as the objective function, it proposes to solve the model based on the ICA and the optimized cuckoo search algorithm. The method is able to effectively schedule the microgrid objective function based on the conditions, with the ability to quickly solve the scheduling problem and greatly reduce the system’s electricity cost. It can greatly increase the utilization rate of photovoltaic power generation. The method has a small amount of computation, small storage, and simple operation. An empirical study is carried out on the designed microgrid optimal scheduling scheme.
Detection of false data injection attacks in smart grid based on adaptive inhibition unscented Kalman filter
Authors: Zhang Guoqing , Gao Wengen , Zhu Jiaming , Li Yaru
Published: June 2024

False data injection attacks (FDIAs) cause incorrect system states by tampering with measurements, seriously affecting the EMS’s control process. However, the well-designed FDIAs can bypass traditional bad data detection (BDD) mechanisms. Aiming at the challenge, we improve the unscented Kalman filter and combine AIUKF with weighted least squares (WLS) to detect FDIAs. Utilizing the different convergence rates of the two estimators, the cosine similarity is introduced for FDIA detection. Various test conditions in IEEE-14-bus are simulated to underline the capability of AIUKF in state estimation. The results indicate that the proposed detection approach is superior for detecting FDIAs.
A wind farm planning method considering frequency security constraint based on wind farm participation in primary frequency regulation
Authors: Jin Chu , Liu Ruoping , Zuo Zhengmin , Luo Shuxin , Li Zuohong , Liu Shengfu
Published: June 2024

Renewable energy sources such as wind power, connected to the grid on a large scale, reduce the rotational inertia and frequency regulation of the power system. Many studies have included frequency security constraints (FSC) in power system scheduling to ensure system frequency stability, but few studies have included FSC in grid planning. Therefore, this paper establishes a planning model for wind farms that considers the FSC based on the wind turbines’ participation in the primary frequency regulation (PFR) by obtaining the maximum deviation value constraint of the system frequency through the system frequency response (SFR) model. Tests were conducted on the IEE30-node system, and the results show that the proposed model enhances the system frequency response capability and ensures system security.
Analysis of power system frequency and active power based on wind-storage combined frequency modulation system
Authors: Xiao Xinyu , Xie Wei , Li Bingjie
Published: June 2024

To solve the problem of frequency and active power regulation of power systems, this paper proposes a wind-storage combined frequency modulation strategy. The mathematical models of doubly-fed induction machines, pump turbines, and wind turbines are established. Based on wind power frequency modulation, the doubly-fed variable-speed pumped storage unit is added to establish a combined frequency modulation system, and a simulation model on Simulink to analyze the participation of different parts of the combined system in frequency modulation and the active power output of the unit when the load changes. The simulation results show that when the load increases or decreases, the addition of a doubly-fed variable speed pumped storage unit can effectively improve the frequency modulation performance of the system, reduce the fluctuation numbers and amplitude, and reduce the deviation after stabilization. By changing its active power output, a new balance of the system power can be reached, which is conducive to the secure and steady functioning of the power system.
Differential protection of distribution lines based on Hausdorff algorithm
Authors: Kang Lei
Published: June 2024

Given the weak time synchronization capability of the feeder terminal unit (FTU) in the distribution network, a new differential protection method for the distribution network is proposed. The method uses the abrupt change of the phase current as the starting criterion, then sends a phase current sampling sequence of power frequency period to the associated FTU, and determines whether the fault occurs in the section by calculating the Hausdorff distance between the sample sequences of the associated FTU current. This algorithm needs no voltage information and the calculation amount is small, making it suitable for multi-branch lines and accurately identifying faults inside and outside the area. A large number of simulation experiments show that the protection scheme has a 4 ms anti-synchronization error capability and is basically unaffected by transition resistance, which is suitable for active distribution networks with high penetration of distributed power supply.
Optimized voltage support strategy under asymmetrical faults in power grids
Authors: Wu Xiongyu , Su Shiping
Published: June 2024

Asymmetrical faults in the grid can lead to voltage drops at the grid-connected points, and in serious cases, there is also a risk of cutting the machine. The traditional voltage support strategy is easily affected by the output of the units and cannot support the voltage flexibly. To address the above problems, an optimized strategy for boosting voltage performance is proposed under asymmetrical faults in the power grid. Firstly, the voltage support principle under asymmetrical fault is analyzed, and the voltage support equation is derived. Then, based on the above equations, an optimal voltage support strategy under asymmetrical faults is proposed by taking the operation requirements of grid-connected standard voltage as the objective and considering the peak current and active power fluctuation amplitude as the constraints. Finally, the effectiveness and flexibility of the above strategy are validated by simulation.
Research on the construction method of virtual mapping digital twin system for substation
Authors: Li Chunbo , Yin Hong , Zhang Linkang , Ma Qing , Niu Zhimin , Liu Shourui
Published: June 2024

At present, there are problems in the process of fault location and cause analysis in the actual work of substations, such as long time consumption, high investment in manpower and material resources, and low returns. A Digital Twin (DT) system construction method that can be used for virtual mapping in substations is proposed to address this problem. Firstly, the design principles and overall structure of the substation DT system were formulated by comprehensively considering the needs of transient modeling, debugging, and verification calculations in the substation. Then, the construction method and process of the three-dimensional twin model of the primary system (PS) in the substation were analyzed by using SolidWorks and Unity3D, and the graphical modeling method and process of the general protection and secondary circuit logic modules were analyzed by using the Cybersim integrated simulation support system. Finally, a three-dimensional twin model of the PS and secondary system (SS) equipment inside the substation was constructed. The reliability of the proposed method was verified through simulation experiments, and the results showed that the fault identification accuracy, fault location accuracy, and fault cause judgment accuracy were the highest during bus faults, with 96.10%, 94.17%, and 92.93%, respectively. The capacitor had the lowest accuracy, with 94.86%, 92.96%, and 91.73%, respectively. The DT system can accurately achieve functions such as status viewing and alarm of the substation, precise positioning and navigation of equipment, and positioning of faulty and abnormal equipment.
Robust optimization scheduling of microgrid considering a tiered carbon trading mechanism and flexible loads
Authors: Li Xiaoxu , Yang Qianjie , Qin Wenping
Published: June 2024

Considering the comprehensive demand response, stepwise carbon trading, and uncertainty of wind power output for cogeneration microgrids, relevant optimization scheduling research will be carried out. The electric heating load is divided into non-dispatchable electric heating load and dispatchable electric heating load. By introducing electric heating demand and tiered carbon trading, the economic and low-carbon operation of microgrids can be achieved. The fluctuation of the output of new energy units is reflected using probability scenario sets in statistics, and a robust optimization model with related distributions is constructed using the C&CG algorithm to calculate and solve the established model. The simulation and comparison of numerical examples show that the microgrid energy management scheme formulated by the model established in this paper has good economic and environmental friendliness, and it also simultaneously validated the superiority of distributed robust optimization methods over traditional optimization methods
Dynamic hierarchical partitioning method of flexible resource for virtual power plant based on event triggering
Authors: Niu Zhenyong , Tang Junbo , Chang Chen , Gao Ciwei , Guo Jie , Cao Renwei
Published: June 2024

With the advantage of efficient aggregation of flexible resources on the demand side, virtual power plants have been widely considered as one of the effective solutions to solve the lack of large-scale access systems and regulation capacity of new energy. Aiming at the problem of how the flexible resources of the virtual power plant can effectively participate in the optimal operation of hierarchical zoning of the power grid, this paper takes the aggregation of flexible resources of the virtual power plant to alleviate multiple line overload as an example. By deducing the transfer factor matrix under the linearized AC power flow model, an event-triggered hierarchical zoning method of flexible resources of virtual power plants considering resource effectiveness is proposed. The effectiveness of the algorithm is verified in several network examples, which provides a new idea for the virtual power plant to participate in the optimal operation of various levels and regions of the power grid.
Defect test of substation grounding grid based on impulse response
Authors: Huang Shengping , Yuan Peng , Xie Zhuochen , Yan Wei , Qin Feilong , Meng Jianan , Wei Ke , Shao Bo
Published: June 2024

The substation grounding grid has been in the open air for a long time, and it is prone to problems such as fracture and desoldering, which leads to a decrease in grounding capacity and becomes a threatening factor affecting the normal operation of the substation. Based on the principle of state response, this paper demonstrates the feasibility of using impulse current to evaluate the defects of the grounding grid, constructs an impulse impedance test system, and conducts defect detection tests on 8 m×8 m (2 m equal intervals) and 28 m×25 m (unequal interval) grounding grids in the laboratory. It analyzes the measured impulse impedance and amplitude-frequency response curves. After testing the grounding grid of a substation of a power grid company, the test results show that the test system based on the principle of state response is effective. The response voltage waveform and amplitude-frequency response curve when detecting the conductor fracture of the grounding grid are different from the waveform curve when there is no defect. It can be applied to the defect evaluation of the grounding grid and has a certain reference value for practical engineering applications.
Research on the adjustable range of air conditioner setting temperature considering user comfort
Authors: Xu Haowen , Li Lei , Yao Yu , Yan Huajiang , Jin Jiahong , Ma Junda
Published: June 2024

Traditional air conditioner (AC) temperature control typically sets temperature goals or establishes a uniform temperature range without considering industrial characteristics and user comfort preferences. As a result, users cannot achieve differentiated and precise control. This paper proposes a data-driven approach to predict the range of AC set temperatures under the constraint of user comfort. Firstly, a random forest feature importance screening method is employed to extract key factors influencing AC set temperatures. Secondly, a convolutional neural network (CNN) model is constructed to estimate AC set temperatures for five typical user categories. Finally, based on the Predicted Mean Vote (PMV) model, user thermal comfort constraints are established to calculate the flexible adjustment range of AC for users. Through simulation analysis using real AC data from a certain region in Eastern China, the proposed standard for estimating user air conditioner set temperatures in this paper ensures a root mean square error not exceeding 0.5 and an average absolute percentage error not surpassing 1.8%. The obtained air conditioner adjustment ranges reflect the characteristics of users in different industries, meeting engineering requirements.
Inhibition characteristics of pollution accumulation in high-voltage direct current conductors with XLPE and PVC film
Authors: Jiang Yuze , Wei Qingquan , Zhang Xuekai , Su Shancheng , Lu Guanglu , An Jiutao
Published: June 2024

The inhibition of pollution accumulation on the ground equipment by cross-linked polyethylene (XLPE) and polyvinyl chloride (PVC) as coating materials was investigated, and the effects of discharge voltage, power supply polarity, and the material properties of ground equipment on the characteristics of dirt accumulation were discussed. When the voltage was greater than 40 kV, the pollution accumulation of the sampling plate of the PVC-coated conductor was higher than that of the XLPE-coated conductor. Whether it was PVC or XLPE coated wire, the amount of pollution accumulation under negative polarity power was greater than that under positive polarity power. When the ground equipment was made of aluminum sheets, the amount of pollution accumulated was greater than that of the PTFE. As the film thickness increased, the amount of pollution on the aluminum fouling film decreased continuously.
Numerical simulation study of the effect of different factors on supercritical CO2 BLEVE
Authors: Liu Chuang , Li Mingzhi , He Yunwei , Shi Xiaohui , Liu Zhenyi , Li Pengliang , Zhao Yao
Published: June 2024

Global warming is harmful to the environment and CO2 is one of the major greenhouse gases. CCS-EOR technology can increase oil production and sequester CO2. During the storage and transportation of high-pressure CO2, BLEVE may occur. In this study, the dynamic pressure parameters in the supercritical CO2 BLEVE process were numerically simulated by using numerical simulation, and the effects of initial temperature and initial charge on the dynamic pressure parameters in the supercritical CO2 BLEVE process were mainly discussed. By thoroughly investigating the dynamic pressure of BLEVE of supercritical CO2, we can better understand and predict the conditions under which such accidents occur, and further improve the safety of industrial processes.
Study on voltage consistency characteristics of lithium-ion battery energy storage system
Authors: Li Gang , Kong Jinliang , Song Litao , Zhu Yong , Liu Mingyi , Liu Chenghao , Wang Jianxing
Published: June 2024

In the long-term operation of lithium-ion battery energy storage power stations, the consistency of batteries, as an important indicator representing the operation condition of the system, needs to be focused. In practice, the parameters of voltage, capacity, and internal resistance are most commonly used for the consistency evaluation of batteries, and voltage is the most intuitive one. In this paper, a real lithium-ion battery energy storage power station is studied, and the consistency of voltages is calculated. The results show that, with the decline of the battery capacity during discharge, the consistency of the battery presents a strong nonlinear characteristic. At the beginning of discharge, the max-min and standard deviation of voltage are only 0.04 and 0.01 V, while at the end of discharge, the max-min and standard deviation of voltage are up to 0.25 V and 0.045 V, respectively. At about 40-50 minutes of the discharge, i.e., when the corresponding voltages are about 3.132 V to 3.176 V, the voltage consistency deteriorates rapidly. Then, this period of discharge is considered as a threshold interval of consistency deterioration of batteries. The results are helpful for system condition evaluation and operation optimization.
Multi-objective optimization and scheduling research on electric bicycle charging and discharging in distribution networks
Authors: Zhang Zongming , Ming Liang , Chen Zhuo , Li Lei
Published: June 2024

With the continuous development of urbanization, the rapid growth of electric bicycles has become a prominent trend. The number of battery-swapping stations for convenient battery replacement has also increased. The large-scale and unregulated connection of electric bicycles and battery-swapping stations to the power grid can significantly impact the distribution network, leading to localized overloads and affecting grid stability. Therefore, this paper proposes a multi-objective optimization scheduling strategy for electric bicycle charging and dis-charging based on both the transmission and distribution systems. Firstly, in the transmission system, the objective is to reduce the operating costs of generators and user charging costs. Sub-sequently, in the distribution system, the goal is to minimize network losses, considering system constraints and the spatial migration characteristics of electric bicycles. The study establishes a multi-objective optimization problem. Simulation analyses were conducted on the power system models based on a standard 10-machine transmission network and an IEEE 33-node distribution network to verify the effectiveness of the proposed multi-objective optimization scheduling strategy.
Risk analysis of lithium battery energy storage systems under typical failures
Authors: Zhang Weijun , Li Zhicheng , Zhang Shuling , Deng Chaoping , Li Biao , Chen Dawei , Lu Yingquan , Deng Yeqiang , Gu Xiaolong , Wang Yu
Published: June 2024

With the rapid increase in the proportion of new energy installed capacity, to solve the problem of new energy output volatility, lithium-ion battery energy storage has developed rapidly by its electrical characteristics and economic advantages and has become a hot spot for the large-scale application of electrochemical energy storage, but it is also accompanied by safety problems such as battery short-circuit and thermal runaway. Based on the typical structure of the lithium battery energy storage system, this paper establishes a complete simulation model of the lithium battery energy storage system, calculates the change rule of battery system electrical parameters inside the battery module under different types of short-circuit faults, and summarizes the fault characteristics and risks of lithium battery energy storage system under different faults. The study shows that short-circuit faults inside the battery module will cause significant fluctuations in the terminal voltage and current of the battery system. The internal short-circuit faults will increase the inter-cluster circulating current. In contrast, the larger short-circuit current will not only cause the local battery cells to overcharge and over-discharge but also trigger the thermal runaway of the battery system.
Study on the relationship between electric field perception and distance factor of direct current overhead line
Authors: Yuan Chenyin , Chen Yuxing , Liu Xinyi
Published: June 2024

The main reason for line collision accidents in offline construction is that construction personnel have an insufficient perception of distance. In the range of viewing angles, due to the lack of reference objects, people lack a correct judgment of the actual height of overhead lines. Voltage, as the most direct electrical volume, has always been a key indicator of electrical protection. In this paper, the feasibility of electrostatic induction is verified through the combination of electrostatic field simulation and experiment, and the influencing factors of electrostatic induction are studied. The results show that electrostatic induction is strongly related to the environmental angle, and the inductive voltage increases with the increase of the high voltage side, and the increased amplitude gradually increases. In addition, the induction distance and the shape of the receiving antenna have an impact on the effect of electrostatic induction. However, the induction distance has the greatest influence on the electrostatic induction effect, followed by the length and diameter of the induction conductor. The research of this paper plays a technical guiding role in the distance measurement of transmission lines based on electric fields.
A clock synchronization and trigger distribution scheme for China Spallation Neutron Source
Authors: Li J. , Cao P. , Wang Y. , Wang W.
Published: June 2024

China Spallation Neutron Source (CSNS) is a complex system
engineering composed of particle accelerators, a target station, and
neutron spectrometers with various equipment types and
distribution. The collaborative operation of the equipment requires
accurate clock synchronization and trigger distribution. Currently,
to meet the requirements of different system devices, clock
synchronization and trigger distribution in CSNS are implemented
based on different methods, resulting in complex clock and trigger
networks, demanding upgrades, and a lack of unified timestamps. This
paper proposes a clock synchronization and trigger distribution
scheme based on the field-programmable gate array (FPGA) and
single-mode dual-core fiber link. The decoupling of clock phase
synchronization and time base synchronization improves the frequency
of phase compensation. Benefiting from the phase interpolator (PI)
in the FPGA transceivers, high-precision phase compensation and
phase deterministic control are realized, achieving picoseconds
synchronization precision and stability in the four-level
network. Based on the custom lightweight link layer protocol, by
optimizing the routing method of data frames and adopting priority
control, the transmission of multiple data is realized, and the
hardware delay of the critical data, such as interlock, is
guaranteed to be less than 1.5 μs in the four-level system. The
scheme provides a general precise clock synchronization and
distributed trigger method for CSNS devices, simplifies the system
complexity, and is conducive to the system upgrade in the second
stage.
Assessing environmental and market implications of steel decarbonisation strategies: a hybrid input-output model for the European union
Authors: Rinaldi Lorenzo , Ghezzi Debora , Colombo Emanuela , Rocco Matteo Vincenzo
Published: June 2024

As a key material for manufacturing clean energy technologies, steel is crucial for energy transition, but its production causes 2.6 Gton of CO2 emissions at global level each year. In 2020 the European Union (EU) set a net-zero emissions target by 2050, fostering innovation in the steel industry to reduce its environmental impact. However, a scenario-oriented and technologically comprehensive analysis assessing prospected environmental and market implications of steel decarbonisation strategies remains a gap, which is addressed in this paper. The analysis adopts a hybrid input-output-based life-cycle assessment model built in the MARIO framework, extending the Exiobase database to represent the supply chains of the most promising low-carbon steelmaking technologies in the EU, such as hydrogen- or charcoal-injected blast furnaces and natural gas- and hydrogen-based direct reduction routes. The penetration of these technologies is explored by formulating scenarios resembling European climate targets. The results show a reduction in the carbon footprint of steel across all scenarios, ranging up to −26% in 2030 and to −60% in 2050. However, the extent of footprint reduction is highly dependent on the share of clean electricity in the European supply mix, highlighting the relevance of holistic decarbonisation strategies. Economic implications affect steel prices, which rise up to 25% in 2030 and 56% in 2050, opening discussions on the need for suitable policies such as CBAM to avoid protectionism and encourage international technological progress.