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    Review of Key Technologies in New Power System Based on Artificial Intelligence Empowerment
    DUAN Junfeng, LI Chenkun, YAO Wenxuan, GUO Siyuan
    Hunan Electric Power    2024, 44 (1): 1-10.   DOI: 10.3969/j.issn.1008-0198.2024.01.001
    Abstract1278)      PDF(pc) (5512KB)(1197)       Save
    Based on the important role of artificial intelligence technology in promoting the intelligence of new power systems, this paper summarizes the current application status, technical challenges, and future development directions of artificial intelligence in new power systems. Firstly,the paper introduce the characteristics and requirements of the new power system. Then, the paper discusses the key application areas of artificial intelligence in new power systems, including the security, stability and control of large power grids, integrated collaborative analysis of source network, load storage, intelligent operation, inspection and management of power systems, as well as active distribution networks and microgrids. Finally, the paper analyzes the technical challenges faced by artificial intelligence in the new power system and proposes relevant suggestions.
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    Summary of Reliability Research on High Voltage Electrical Device in Substation
    MA Zhaoxing, CHEN Hao, TANG Yi, SHA Haoyuan, JIANG Minyi
    Hunan Electric Power    2023, 43 (2): 53-59.   DOI: 10.3969/j.issn.1008-0198.2023.02.009
    Abstract374)      PDF(pc) (1104KB)(658)       Save
    Based on the reliability research of high-voltage electrical equipment in substations, this paper introduces the development of the reliability research of high-voltage electrical equipment, discusses the reliability analysis methods of common electrical equipment, and compares the advantages and disadvantages of the analytical and analog methods, the optimal application situation is analyzed, and the combination method and state method under complex system are studied. The future trend of reliability analysis based on multi-methods cross-fusion is prospected.
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    Remarks from Invited Editor in Chief
    LI Peng, SHU Shengwen, QIU Zhibin
    Hunan Electric Power    2024, 44 (3): 1-2.  
    Abstract114)      PDF(pc) (1569KB)(613)       Save
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    Research Progress on Safety Performance Improvement of Lithium-Ion Batteries
    HE Dan, HU Xiongxiong, CUI Hao
    Hunan Electric Power    2024, 44 (3): 25-33.   DOI: 10.3969/j.issn.1008-0198.2024.03.004
    Abstract467)      PDF(pc) (6708KB)(606)       Save
    :Aiming at the thermal runaway of lithium ion battery and fire fighting technology, the existing types of fire extinguishing agents are introduced, their fire extinguishing mechanism and advantages and disadvantages are analyzed, the mechanism and evolution process of thermal runaway of lithium ion battery are studied, and the future of lithium ion battery fire extinguishing agents is prospected.The research results show that these fire extinguishing agents meet the basic characteristics of extinguishing open fire when dealing with lithium-ion battery fires, but there are still different degrees of reignition risk, fire extinguishing time and flame retardant effect are not the same,in addition some fire extinguishing agents will have a negative impact on the environment and equipment after use. Therefore, the development of new fire extinguishing agents with high efficiency,environmental protection and anti-reignition characteristics is an inevitable trend of future research.
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    Analysis on Influence of Separate Operation of 500 kV Bus of UHV Xiaoxiang Station on Hunan Power Grid
    LIU Yongyan, GAN Wangwei, ZHANG Yan, XIAO Pei, CUI Ting, GUO Hu
    Hunan Electric Power    2023, 43 (2): 112-116.   DOI: 10.3969/j.issn.1008-0198.2023.02.019
    Abstract257)      PDF(pc) (2529KB)(567)       Save
    After the commissioning of the 1 000 kV UHV AC double-circuit line from Xiaoxiang—Ganjiang, the reactive power support capability of the inter-provincial AC channels has been enhanced, and the system stability has been enhanced, but it also leads to the increase of the system short-circuit current. In order to ensure the transient voltage stability of Hunan power grid, it is still necessary to put forward the requirements for the start-up and rotation of units in the province, which limits the power supply capacity and operational flexibility of the power grid. Aiming at this problem, the optimization of 500 kV grid structure in Hunan power grid is studied, and the optimization scheme of 500 kV bus-bar operation in UHV Xiaoxiang station is put forward to reduce the impact of near-area short-circuit fault on the system. It can improve the transient voltage stability level and the power supply capacity of power grid, and provide technical support for the safe and stable operation of Hunan power grid.
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    Governance Method of Power Quality in New Power Distribution Area Based on Energy Storage System
    LAN Zheng, YIN Rui, ZOU Bin, HE Dong
    Hunan Electric Power    2023, 43 (4): 56-62.   DOI: 10.3969/j.issn.1008-0198.2023.04.008
    Abstract267)      PDF(pc) (3308KB)(530)       Save
    In the new power distribution area, due to the wide application of power electronic devices and the access of a large number of distributed energy sources, the power quality of the new power distribution area is seriously affected and the power fluctuation is caused. In order to improve the power quality and power fluctuation of the new power distribution area, a new power quality management method based on energy storage system is proposed. This method can improve the comprehensive adjusting ability of the energy storage system at the head of the area. It can not only control the current harmonics, reactive power and unbalance current of the new power distribution area, but also stabilize the active power effectively. Firstly, the structure of the new power distribution area and the topology of the energy storage system are introduced, and the mathematical model is built. Then, in the harmonic detection section of the control section, the four-wire ip-iq harmonic detection method based on moving mean filter is adopted. And in the process of energy storage power adjustment, the strategy of battery charging and discharging considering energy storage capacity is adopted. At the same time, the command current is accurately tracked by repetitive control and PI control. Finally, the simulation results show that the proposed energy storage system and its control strategy can not only effectively improve the power quality of the new power distribution area, but also smooth the active power fluctuation.
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    Dielectric Properties and Structural Design of Main Insulation for Oil-Impregnated Paper Capacitive Bushing
    LIU Daosheng, ZOU Bin, CHEN Xingrong, WANG Shihui
    Hunan Electric Power    2023, 43 (2): 19-23.   DOI: 10.3969/j.issn.1008-0198.2023.02.004
    Abstract362)      PDF(pc) (2837KB)(488)       Save
    Oil-impregnated paper capacitive bushing, as one of the core current-carrying components of a transformer, has functions of support, current diversion and insulation. The insulation performance is crucial to the stability and safety of transformer operation. In order to reduce insulation faults caused by oil-paper partial discharge during the operation of oil-immersed paper bushings, this paper adopts nano-modulation technology to improve the dielectric and electrical properties of oil-immersed insulating paper for the main insulation of bushings. Taking 20 kV oil-paper capacitor bushing as the research object, a combination of simulation and experiment is used to investigate the effect of nanoparticles on the electric field distribution and partial discharge initial voltage of the main insulation of the casing core. The experimental results show that the nano-TiO2 particles can improve the surface microstructure of insulating paper, reduce the relative dielectric constant and the peak electric field intensity in the casing core, and increase the partial discharge initial voltage of the casing core. This provides a reference for improving the insulation performance of oil-paper capacitive bushings.
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    Day-Ahead Scheduling of Integrated Electric Heating System Considering Thermal Inertia
    DAI Mengdi, KE Deping, SONG Lin, WANG Huiji
    Hunan Electric Power    2023, 43 (2): 32-38.   DOI: 10.3969/j.issn.1008-0198.2023.02.006
    Abstract268)      PDF(pc) (2463KB)(470)       Save
    For the problem of optimal scheduling of integrated energy systems involving wind power consumption, a stochastic optimal scheduling strategy with systematic consideration of mixed uncertainties is proposed by mining multiple thermal inertia. The thermal inertia of the network based on the dynamic characteristics of the heat network and the thermal storage characteristics is explored, the thermal load elasticity constraint is introduced into the modeling of thermal inertia of buildings, and heat pumps and thermal storage are used as time-shiftable electric loads and heat sources, which are jointly modeled with CHP units to solve the peak-valley mismatch of electric and thermal loads.On this basis, the IES model considering multiple thermal inertia is established, the coupled system of 33-node heat network and 9-node grid is used as an example for the analysis. And the traditional heuristic particle swarm algorithm with the mixed integer nonlinear programming algorithm is compared. The results show that by mining the multiple thermal inertia to broad the flexibility of the energy system, the complementary aid and flexible dispatch between multiple heterogeneous energy sources can be realized, and the mathematical planning algorithm can effectively improve the solving efficiency far than the particle swarm algorithm.
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    Analysis and Research of On-Line Energy Consumption Monitoring Model for Thermal Power Units
    NIE Tao, SHAO Feng, YANG Wenzheng, HE Xinrong , WANG Zhong′ao
    Hunan Electric Power    2023, 43 (2): 60-65.   DOI: 10.3969/j.issn.1008-0198.2023.02.010
    Abstract271)      PDF(pc) (1192KB)(468)       Save
    Because of the limitation of on-line energy consumption measurement condition and instrument measurement precision, the coal consumption of on-line monitoring system usually has big error.To solve this technical problem, this paper adopts the state equation of thermal economy of power plant to dynamically solve the steam turbine heat rate, applying the idea of energy mass balance, the steam water distribution matrix equation of the whole thermal system is established.At the same time, the dynamic fluctuation characteristics of boiler efficiency are deeply studied, the factors of coal quality ash and heat dissipation are analyzed , the theoretical calculation models of exhaust heat loss, solid incomplete combustion heat loss and heat dissipation loss are established.For the dynamic calculation of auxiliary power consumption rate, the emphasis is on the accuracy of the electric meter and the allocation method of the public part of the power supplied to the factory. The online calculation accuracy of the unit energy consumption model is verified and the test results show that the on-line energy consumption calculation and monitoring model can meet the accuracy requirements of ASME standards.
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    Control Strategy of LCL Grid-Connected Inverter Based on Improved Weighted Current Control
    LING Zhiyong, ZHOU Zhifei, LI Shengqing, YAO Hongde
    Hunan Electric Power    2023, 43 (2): 39-45.   DOI: 10.3969/j.issn.1008-0198.2023.02.007
    Abstract323)      PDF(pc) (4395KB)(459)       Save
    Aiming at the problems that the traditional weighted average current (WAC)control strategy does not consider the digital control delay, and causes the phase lag of the system, which leads to the reduction of system bandwidth and poor robustness, the WAC control strategy of combination of quasi-proportional resonance control and lead compensator is proposed. Firstly, the capacitor current feedback is introduced to suppress the reverse resonance peak. Secondly, the lead compensator is connected in series at the transfer function of the inverter bridge to improve the phase margin of the system. Finally, the quasi-proportional resonant controller is used as a current regulator to Increase the fundamental frequency gain and reduce the static error of the system. It is verified by simulation that the proposed control strategy has good adaptability to weak power grids, and the harmonic distortion rate of grid-connected current is reduced from 1.84% to 0.26%, thereby enhancing the robustness of the system and improving the quality of grid-connected current.
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    10 kV Feeder Load Forecasting Method Based on Double Layer Mapping
    GUO Lu, LIU Yongli, LI Longfei, HE Ming, YANG Huimin, ZHANG Yuan, WU Qian
    Hunan Electric Power    2023, 43 (2): 71-78.   DOI: 10.3969/j.issn.1008-0198.2023.02.012
    Abstract285)      PDF(pc) (1788KB)(417)       Save
    Feeder load is very important for distribution system planning, safe operation, equipment maintenance and load analysis, etc. This paper uses the spatial load forecasting method to indirectly realize electrical load forecasting, which is suitable for the load forecasting of 10 kV feeders under the situation that the purpose of spatial land is clear, the historical data of parcel load is sufficient, but the historical data of feeder electrical load is relatively lacking. According to the“component-parcel”spatial membership relationship, the micro electrical load forecasting based on the feeder segment is indirectly realized by means of the spatial parcel load forecasting, and further summarizes the medium and long-term loads of the entire 10 kV feeder line. The core idea is to first map the electrical load of the current year to the spatial load, and then obtain the spatial load of the required planning year through the spatial load prediction, and then map the spatial load of the planning year to the electrical load, and finally summarize the predicted load of the feeder. The results of the example are compared with the existing mainstream forecasting methods and the actual load collection data respectively. It shows that the proposed model and calculation method meet the accuracy requirements of distribution network planning, and it is practical and effective.
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    Capacity Optimization Configuration of Grid-Connected Wind-Solar-Hydrogen-Storage Microgrid
    ZHAO Na, ZHANG Lian, WANG Shibin, LI Duo, HUANG Wei
    Hunan Electric Power    2023, 43 (4): 48-55.   DOI: 10.3969/j.issn.1008-0198.2023.04.007
    Abstract261)      PDF(pc) (1469KB)(367)       Save
    A single type of energy storage device is difficult to take into account the advantages of multiple types of energy storage devices, while the hybrid energy storage system can integrate the technical and economic advantages of different types of energy storage. Aiming at the optimal configuration of hybrid energy storage based on battery and hydrogen energy storage in grid-connected mode, economic and environmental protection are taken as the objective function, the analytic hierarchy process is used to solve the multi-objective weight problem, and the particle swarm optimization algorithm is used to solve the optimal configuration of microgrid capacity. Different energy storage configuration schemes are analyzed and compared by economy and evaluation index. The results show that the cost of hybrid energy storage is 2.46% and 10.02% lower than that of single battery and hydrogen energy storage. The self-balancing rate is 7.65% and 23.89% higher than that of single battery and hydrogen energy storage, and the redundancy is 19% and 38.16% lower than that of single battery and hydrogen energy storage.
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    Prediction of Power Transmission Project Cost Trend Based on Big Data
    DENG Yiqing, SUN Bin, LI Xiaobing, LI Dan, WANG Rongjing
    Hunan Electric Power    2023, 43 (2): 108-111.   DOI: 10.3969/j.issn.1008-0198.2023.02.018
    Abstract374)      PDF(pc) (1317KB)(354)       Save
    In order to accurately predict the cost of power transmission and transformation projects, control the cost investment in the construction stage, and improve the utilization rate of funds,based on the actual cost data of power transmission and transformation projects in different cities in Shaanxi province, the key influencing factors of power grid project cost are screened by using the entropy weight method, and the BP neural network forecasting model is used to predict the cost of transmission and transformation projects effectively. The forecasting results confirm the validity of the model.
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    Development of Mobile Energy Storage Vehicle Based on Super Capacitor Battery
    WU Chuanping, ZHOU Tiannian, LIU Yu, ZHU Hongzhang
    Hunan Electric Power    2023, 43 (2): 66-70.   DOI: 10.3969/j.issn.1008-0198.2023.02.011
    Abstract315)      PDF(pc) (5822KB)(325)       Save
    Aiming at a new type of mobile energy storage vehicle using electrical double-layer capacitor, this paper introduces the electrical double-layer capacitor characteristics, the structure of mobile energy storage vehicle and the electrical double-layer capacitor package assembly scheme, puts forward the control method and working mode of energy storage power converter, designs the fire protection system of the device, and carries out the functional test on electrical double-layer capacitor mobile energy storage vehicle. The test results show that electrical double-layer capacitor mobile energy storage vehicle runs well in charging, discharging and islanding mode when connected to the grid, with high energy conversion efficiency and good application prospects.
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    Hunan Electric Power    2023, 43 (2): 1-2.  
    Abstract140)      PDF(pc) (1027KB)(315)       Save
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    Effect of Organic Pollutant Infiltration on Anti-Flashover Performance of Methyl Silica Superhydrophobic Coatings
    WANG Shengwu, ZOU Qiaoge, LI Li, CHEN Junwu, XIE Yi
    Hunan Electric Power    2023, 43 (2): 3-7.   DOI: 10.3969/j.issn.1008-0198.2023.02.001
    Abstract230)      PDF(pc) (3667KB)(314)       Save
    The deposition and infiltration of organic pollutants on the surface of methyl silica superhydrophobic coatings will lead to a decrease in the self-cleaning properties of the coatings, which in turn will lead to a decrease in the insulation strength of the coatings under dirty and wet environmental conditions. There is a lack of research on the effect of organic fouling on the insulation strength of methyl silica superhydrophobic coatings. The insulation strength of the coating samples under dirty and wet conditions is reflected by measuring the leakage current amplitude of the coating samples after they are wetted with alkane organic substances in different degrees and ways. The results show that the leakage current amplitude of the surface of methyl silica superhydrophobic coating increases by more than 50% when the infiltration area of organic pollution is increased to 3 times under the experimental conditions. The leakage current amplitude of the coating is decreased by about 16% by increasing the dispersion degree of organic pollution sites. Under the experimental conditions of heavy organic infiltration, the static contact angle and rolling angle of methyl silica super-hydrophobic coating drops are decreased by 10° and increased by more than 7° respectively.
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    Design and Simulation of Power Supply-Traction-Hybrid Energy Storage System for Urban Rail Trains
    ZHU Zhiqiang, WANG Xin, QIN Bin
    Hunan Electric Power    2024, 44 (1): 24-31.   DOI: 10.3969/j.issn.1008-0198.2024.01.004
    Abstract499)      PDF(pc) (7016KB)(314)       Save
    In order to further improve the recovery and utilization efficiency of urban rail train regenerative braking energy, a structure of urban rail train traction power supply system based on distributed ground hybrid energy storage is designed through the analysis of system functional requirements, and the power supply network, train traction and energy storage system models are established. Moreover, aiming at the problem that low pass filtering leads to a large amount of power exchange between lithium batteries and supercapacitors, a stepped power allocation method with supercapacitor compensation is proposed.This method has small computation and strong real-time performance,and can avoid the internal power circulation of the hybrid energy storage system. Combined with the proposed model and strategy, MATLAB Simulink is used to simulate.The results validate that the energy utilization efficiency of the hybrid energy storage system is improved by 1.39%, the voltage regulation rate is increased by 12.75% and the energy saving rate is increased by 6.72%.
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    Research on Monitoring and Management of Wind Power Generation Capacity in Hunan Power Grid
    CHEN Haoqi, WU Yuxiang, FAN Jiahong, QIAN Jun, CHEN Bin, ZHU Shu, ZHANG Jinfan
    Hunan Electric Power    2023, 43 (2): 97-101.   DOI: 10.3969/j.issn.1008-0198.2023.02.016
    Abstract469)      PDF(pc) (4797KB)(312)       Save
    In view of the current situation and existing problems of wind power capacity monitoring technology in Hunan power grid, a wind power capacity monitoring algorithm and system architecture based on abnormal data identification are proposed. The feasibility of the algorithm is verified by historical data, which realizes real-time monitoring of wind power plant capacity and automatic detection and identification of wind power plant abnormal data.Based on the monitoring system, the supporting management suggestions are put forward to scientifically guide the improvement of the wind power management level of Hunan power grid, which can improve the wind power supply support ability and promote the development of wind power anti-ice technology.
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    Analysis and Research on Influence of High Temperature and Dry Weather on Regional Power System in 2022 Summer
    BIE Fangmei, FANG Rengcun, WAN Jing, FAN Yuhong, CHEN Xi
    Hunan Electric Power    2023, 43 (4): 108-113.   DOI: 10.3969/j.issn.1008-0198.2023.04.016
    Abstract350)      PDF(pc) (2088KB)(309)       Save
    In view of the difficulties and challenges faced by the power system during the extremely hot weather in summer in 2022, taking the operation of typical provincial power grids as an example, the maximum load, peak load duration and summer power grid load characteristics of the whole network are studied, and the outstanding problems in power supply during the summer vacation are analyzed, so as to put forward countermeasures and suggestions for how to ensure the safe and stable operation and reliable supply of the power system in summer.
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    Electromagnetic-Fluid-Thermal Field Analysis of Power Cable under Vertical Laying Mode
    QU Bo, YANG Juntao, LI Xin, XIANG Xingyao, SHU Shengwen
    Hunan Electric Power    2023, 43 (2): 24-31.   DOI: 10.3969/j.issn.1008-0198.2023.02.005
    Abstract250)      PDF(pc) (4304KB)(291)       Save
    The temperature distribution is one of the key factors that determine the operation of the power cable, and it is mainly affected by the running current, the laying mode and the operating environment. In order to study the temperature distribution characteristics of cables under the vertical laying mode, the paper takes the cable shafts of high-rise buildings as the research object, and builds a simplified three-dimensional multi-physics simulation model of the cable shafts. The finite element method is used to calculate the fluid and temperature distribution inside the cable shafts, and the temperature variation trend is analyzed. Then, the influence of factors such as running current and fire blocking material on the temperature distribution of the cable is comparatively studied. The research results show that compared with the horizontal laying mode, the vertical laying of the cable is more susceptible to the influence of the air flow in-side the cable shaft, resulting in a large difference in the temperature distribution between different parts of the cable. At the same time, the increase of load current and the addition of fire blocking materials will cause the increase of cable temperature and the change of temperature distribution between different floors.
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    Strategy of An Improved Adaptive Sliding Mode Controlling Virtual Synchronous Generator Control Based on Direct-Driven Permanent Magnet Wind Power System
    CHEN Anping, HU Xiaolin, LUO Zhaoxu, CHENG Zhun
    Hunan Electric Power    2023, 43 (4): 63-73.   DOI: 10.3969/j.issn.1008-0198.2023.04.009
    Abstract218)      PDF(pc) (5028KB)(287)       Save
    For the direct-drive permanent magnet synchronous wind generator system, because of the difference of equivalent output impedance between inverters and transmission line impedance, the problems of multi-inverters controlled by traditional virtual synchronous generator (VSG) , such as unequal power distribution and poor circulating current suppression are presented,and an improved adaptive sliding mode control strategy is proposed for multiple VSG power sharing and circulation suppression. The given power calculating is calculated according to the total load capacity and the capacity of each inverter, and the virtual impedance according to the given reactive power to compensate the voltage drop caused by the difference of line impedance is adjusted .The sliding mode control of two VSG is designed in coordinate system, and the sliding mode surface is designed based on the difference between the inverter output voltage and the VSG reference voltage, based on Lyapunov stability theory, an adaptive sliding mode controller is designed, which consists of equivalent control, switching control and adaptive compensation. Compared with the traditional control method, the proposed control strategy power sharing and circulation suppression are achieved , and the distribution accuracy of reactive power and VSG output voltage are improved. Finally, the correctness and validity of the control strategy are verified in MATLAB/Simulink.
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    Power Flow Calculation Method in Loop-Closing Distribution Network Based on Bus Voltage Phasor Acquisition
    CHEN Chenggong, ZHU Yulan, PANG Muchan
    Hunan Electric Power    2023, 43 (2): 102-107.   DOI: 10.3969/j.issn.1008-0198.2023.02.017
    Abstract277)      PDF(pc) (2555KB)(284)       Save
    The traditional calculation method relying on power grid modeling and parameter accuracy is not suitable for the power flow calculation in loop-closing distribution network.To solve this problem, a new power flow algorithm based on bus voltage phasor acquisition is proposed, which can realize the on-line calculation of power flow in distribution network conveniently. The on-line computing module developed based on the algorithm has a good effect, which verifies the validity and practicability of the algorithm.
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    Optimal Efficiency Control Method for Large-Scale Hydrogen Production System from Renewable Energy
    MENG Xin, CHEN Maolin, WANG Xiongzheng, YANG Haoran
    Hunan Electric Power    2023, 43 (3): 2-8.   DOI: 10.3969/j.issn.1008-0198.2023.03.001
    Abstract322)      PDF(pc) (7877KB)(274)       Save
    Large scale hydrogen production from renewable energy is an important technical means to achieve renewable energy consumption and suppress fluctuations. Aiming at the optimal operation of large-scale intermittent renewable energy hydrogen production system, an efficiency optimization control method of parallel hydrogen production units is proposed. Firstly, the efficiency model of hydrogen production units is established. Secondly, by constructing the efficiency optimization objective function and constraints of multiple parallel hydrogen production units, the optimal power distribution value of each parallel hydrogen production device at different input power is optimized by exhaustive optimization algorithm. Finally, the effectiveness and feasibility of the method are verified by MATLAB simulation, and its operating efficiency are compared with the power sharing and hierarchical switching modes. The results show that the efficiency optimization control method can effectively improve the operation efficiency of the parallel system under fluctuating power.
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    Transformer Fault Diagnosis Method of Optimized Hybrid Kernel Extreme Learning Machine Based on Improved Northern Goshawk Optimization Algorithm
    WANG Shibin, LI Duo, ZHAO Na, XIE Wenlong, HUANG Wei, JI Hongyu
    Hunan Electric Power    2023, 43 (4): 125-132.   DOI: 10.3969/j.issn.1008-0198.2023.04.019
    Abstract262)      PDF(pc) (3096KB)(270)       Save
    To improve the accuracy of transformer fault diagnosis, a transformer fault diagnosis method of optimized hybrid kernel extreme learning machine(HKELM)based on improved northern goshawk optimization algorithm(INGO) is proposed. Firstly, the ReliefF algorithm is used to filter and reduce the dimensionality of 19 dimensional transformer fault features. Secondly, three strategies of Logistic tent chaotic mapping, Cauchy mutation operator, and nonlinear increasing weight, are introduced to improve the Northern Hawk optimization algorithm and enhance its global optimization ability. Then, the improved INGO algorithm is used to optimize the initial parameters of HKELM to improve its classification accuracy and robustness. Finally, the features optimized by ReliefF are used as input features for the model and compared with different transformer fault diagnosis models. The simulation results show that the INGO-HKELM fault diagnosis model has higher fault diagnosis accuracy compared to other models.
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    A Condition Estimation Method for DC-link Capacitors Based on Pre-charging Model
    TIAN Rui, LIU Weike, WU Xun
    Hunan Electric Power    2023, 43 (4): 133-138.   DOI: 10.3969/j.issn.1008-0198.2023.04.020
    Abstract184)      PDF(pc) (2074KB)(260)       Save
    DC-link capacitors are key components for energy buffering in converter systems and are widely used in fields such as locomotive traction, aerospace, wind power generation and photovoltaic power generation. In harsh working environments, the performance of DC-link capacitors deteriorates, the failure rate increases, and they are easily damaged. Currently, the existing methods for state identifying of capacitors are easily affected by sensor measurement noise, resulting in a significant difference between the capacitance identification results and the actual values. To solve these problems, this paper proposes a capacitor state identification method based on the pre-charging process. By constructing the pre-charging model, the mapping relationship between capacitance and voltage signal is obtained, and the influence of measurement noise is minimized. Then, the recursive auxiliary variable least square method is used to estimate the parameters of the pre-charging model, so as to obtain the accurate capacitor capacity identification results. The verification results show that this method can effectively resist the interference of measurement noise, and has good identification effect when the signal sampling frequency is greater than 500 Hz. The capacitance identification error is 0.569% when the sampling frequency reaches 1 kHz.
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    Study on Natural Convective Flow Heat Transfer in Supercritical Carbon Dioxide Cavity
    YE Maojing, WU Tianyu, LIU Kairui, WANG Limin, CHE Defu
    Hunan Electric Power    2023, 43 (4): 1-8.   DOI: 10.3969/j.issn.1008-0198.2023.04.001
    Abstract199)      PDF(pc) (4176KB)(246)       Save
    Horizontal flow of supercritical carbon dioxide (S-CO2) will flow stratification under heating or cooling conditions, resulting in different heat transfer phenomena at the top and bottom of the tube. In order to study the flow heat transfer behavior driven by upward lift in vertical flow direction, the development process of S-CO2 natural convection and the influence of pressure, pipe diameter and temperature interval on the development process are studied based on a two-dimensional circular cavity physical model. The results show that the development process of flow heat transfer away from the pseudo-critical temperature range is relatively stable compared with the pseudo-critical temperature range. In the pseudo-critical temperature range, the higher the pressure, the faster the heat transfer development process. In the pseudo-critical temperature range, the larger the diameter of the pipe, the longer the time for heat transfer to reach stability, and the more intense the main flow zone is in the initial stage of development.
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    Load Aggregator Strategic Quotation and Peak Market Clearing Optimization Considering Adjustment Cost
    ZHANG Lingqiao, ZHOU Zhengcheng, SHEN Shasha, XIANG Yunkun, LIU Hanlin, WANG Wei, MENG Ke
    Hunan Electric Power    2023, 43 (4): 24-31.   DOI: 10.3969/j.issn.1008-0198.2023.04.004
    Abstract246)      PDF(pc) (2676KB)(246)       Save
    The access of high proportion of new energy makes the uncertainty of power supply increasing, the unbalance of power supply outstanding and the difference between peak and valley of load increasing. In order to solve the problem of unbalance of power supply and demand during peak hours, a strategic bidding strategy of load aggregator considering adjusting cost and its optimal clearing strategy in peak market are proposed. Firstly, the load aggregator is defined, and the flexible resource is classified according to the characteristics of voltage level, load curve, unit power regulation cost and power consumption characteristics. Secondly,the paper analyzes the characteristics and adjustment potential of various kinds of end-user load, establishes the model of load adjustment cost of various kinds of end-users, and constructs the strategic quotation model, to minimize the sum of load adjustment costs of load aggregators, a clearing model is established. Finally, a typical peak demand response scenario involving a regional load aggregator is taken as an example to demonstrate the validity and scientificity of the proposed method.
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    Research on Short-Term Wind Power Prediction Method of Bidirectional Long Short-Term Memory Based on Variational Mode Decomposition and Sparrow Search Algorithm
    HAO Luxi, LIU Lin, LIU Baiyang, SUN Jieyi, WANG Huijuan
    Hunan Electric Power    2024, 44 (3): 89-95.   DOI: 10.3969/j.issn.1008-0198.2024.03.013
    Abstract220)      PDF(pc) (4521KB)(246)       Save
    :In order to solve the problem of inaccurate short-term power prediction of wind power caused by stochastic and fluctuating wind power, a short-term wind power prediction method based on bi-directional long short-term memory of variational mode decomposition and sparrow search algorithm is proposed.Firstly, the wind power in the historical data is decomposed into several sub-sequences by using variational mode decomposition, and each element in the sub-sequence corresponds to a historical meteorological data vector at a certain moment, which forms the original data matrixs.Then, the bidirectional long short-term memory of sparrow search algorithm power prediction method is used to model several original data matrices respectively, and the optimal parameters of bidirectional long short-term memory (BiLSTM) are automatically found by using sparrow search algorithm, and finally the prediction results are superimposed to form the final prediction results. Based on the actual operation data of a wind farm in Hunan province, the simulation results show that the root mean square error, mean absolute error, and mean absolute percentage error of the proposed model in this article are reduced by 77.29%, 75.52% and 75.04% respectively compared with the BiLSTM model, which can effectively improve the short-term power prediction accuracy of the wind farm.
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    Image Classification Method Based on Deep Learning for Inspection Unmanned Aerial Vehiclesin Transmission Line
    YANG Hongzhao, XI Yanhui, XIANG Sheng, XU Zhikang
    Hunan Electric Power    2024, 44 (1): 53-58.   DOI: 10.3969/j.issn.1008-0198.2024.01.008
    Abstract311)      PDF(pc) (3904KB)(244)       Save
    Due to the irregularity of point cloud data, the classification accuracy of point cloud data feature values is difficult to meet the requirements of transmission line inspection. Therefore,a lidar point cloud classification method based on graph signal processing is proposed. When processing irregular transmission line image signals, the method can directly generate feature values from the original point data, thereby improving classification accuracy. In order to validate the proposed method, the algorithm is validated through physical simulation, and the results show that the classification accuracy in the image could reach 90%.
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    Device of Earth Wire Arc Preventing in 500 kV Substation under Strong Induced Electricity Environment
    ZHANG Yunxiang, WANG Yu, SHENG Huan, LI Sipei, CHEN Hao, ZHU Kai, HE Jiahong
    Hunan Electric Power    2023, 43 (2): 85-89.   DOI: 10.3969/j.issn.1008-0198.2023.02.014
    Abstract272)      PDF(pc) (1542KB)(240)       Save
    The induced voltage of the electrical equipment is too high during the overhaul.When the grounding switch can not be operated, it is necessary to connect the temporary grounding wire. The arc fault will affect the safe operation of the equipment. In this paper an anti-arc device for temporary grounding wire hanging is developed, and a grounding wire switching system based on the current limiting reactor is presented. This system can compensate the instantaneous current, and reduce the overvoltage level. Moreover,when the overvoltage is limited to a reasonable value, the grounding state is switched to direct grounding by control system. The application results show that the device can prevent the grounding arc caused by the induced voltage in the grounding process effectively,has the advantages of convenient installation and high security,and improve the efficiency greatly.
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    LCL Solar Inverter Control Design for Weak Power Grids
    ZENG Lin, ZHU Zan, XU Yong, XIANG Yunkun, HE Zhe
    Hunan Electric Power    2023, 43 (2): 90-96.   DOI: 10.3969/j.issn.1008-0198.2023.02.015
    Abstract248)      PDF(pc) (3180KB)(239)       Save
    The connection of a distributed generation (DG) unit to a weak power grid is challenging due to stability issues resulted from the uncertainty of system impedance. This paper designs controller to improve the performance of grid-connected current feedback control based on μ method. In order to decouple active and reactive components in control system, a multi-input multi-output model reflecting the interaction between the components of d and q is established. The decoupling requirement, together with steady-state error and overshoot is transformed into the design problem of controller. By employing the μ method, the paper designs a robust feedback controller to meet the all requirements. Simulations show that the controller not only guarantees the robust stability and robustness of the system under the uncertainty of the inductance of the power grid, but also realizes the decoupling of the d and q components of the current.
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    Review on Non-Contact Voltage/Electric Field Sensors
    KE Kun, YANG Qing, QIU Zhenhui, LIAO Wei, ZHOU Jianglin
    Hunan Electric Power    2023, 43 (5): 71-78.   DOI: 10.3969/j.issn.1008- 0198.2023.05.011
    Abstract478)      PDF(pc) (9478KB)(239)       Save
    Safe and accurate acquisition of electrical parameter data of the power system can ensure the safe and stable operation of the power system. Compared with traditional voltage measurement, non-contact measurement technology has higher safety because it does not need to have a direct electrical connection with the primary equipment, and has the characteristics of small size, frequency bandwidth, and good transient response characteristics, which can meet the needs of modern power grid distributed sensor networks. This paper introduces in detail the technologies of coupling capacitive voltage sensing, voltage sensing based on current integration method, D-dot electric field sensing, electric field sensing based on electro-optical effect, piezoelectric effect, and electrostatic induction effect, analyzes the advantages and existing problems of the above sensing technology, and introduces the method of electric field inversion voltage. Finally, the development prospect of non-contact voltage/electric field sensing technology is prospected.
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    Research on Distortion Correction Method of Aerial Photovoltaic Module Images
    WANG Jiawen, ZHU Yongcan, WANG Shuai, LI Kefeng
    Hunan Electric Power    2023, 43 (4): 74-79.   DOI: 10.3969/j.issn.1008-0198.2023.04.010
    Abstract329)      PDF(pc) (3609KB)(235)       Save
    Aerial photography of photovoltaic components often suffers from distortion due to shooting angle issues, which affects the measurement, recognition, and classification of elements like straight lines, angles, and proportions. To address this problem, this paper proposes an undistorted aerial photovoltaic component image correction method that requires no calibration. The approach first extracts four critical feature points from the photovoltaic component image using a feature point extraction algorithm and then matches them using a feature point matching algorithm to obtain their corresponding relationships before and after distortion. Secondly, the theoretical principles of computational geometry are utilized to compute the parameters T necessary for distortion correction through triangulation and coordinate transformation of the corresponding points. Finally, distortion correction is carried out on the image using parameter T to obtain the corrected photovoltaic component image. This algorithm not only improves the visual correction effect of the image but also increases the accuracy of data by 20%~55%.This method has a high application value in the foreign object recognition, operation and maintenance of the aerial photovoltaics module image.
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    Experimental Study on Coal Combustion Catalyzed by Metallic Compounds
    RAO Hua, XU Huifang, WU Aijun, BIN Yiyuan, DU Wei, CHENG Shan
    Hunan Electric Power    2023, 43 (5): 85-91.   DOI: 10.3969/j.issn.1008- 0198.2023.05.013
    Abstract186)      PDF(pc) (10252KB)(233)       Save
    The combustion experiment of Hunan bituminous coal was carried out under air atmosphere with the final temperature of 1150 ℃ by thermogravimetric analysis.Different proportions of CaO, Fe2O3, NaCl and MgO in coal was adding to explore the influence of metal compounds on the combustion characteristics of coal. The experimental results show that the ignition temperature can be reduced, and the combustion stability can be improved and the combustion efficiency can be improved by adding a certain amount of metal compounds into the pulverized coal. The metal compounds CaO, Fe2O3, NaCl and MgO have different catalytic effects on the combustion of pulverized coal. The addition of NaCl and Fe2O3 makes the combustion of pulverized coal violent, which is conducive to the burnout of pulverized coal. The effect of NaCl on comprehensive catalytic combustion is the best,and the ignition temperature of the sample with NaCl decreases about 22 ℃.The identification index of Cb ,G and Hj increase with the decrease of MgO percentage, and the flammability is better. The addition of CaO and MgO will increase the ignition temperature of pulverized coal, and the combustion stability and burnout effect of pulverized coal will become worse, and the influence of CaO is greater than that of MgO. The catalytic combustion effect is best when the NaCl content is 8%.
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    Analysis of Common Problems for Current Transformer Secondary Circuit
    YANG Qi, WEI Dong
    Hunan Electric Power    2023, 43 (2): 117-120.   DOI: 10.3969/j.issn.1008-0198.2023.02.020
    Abstract296)      PDF(pc) (2499KB)(232)       Save
    Aiming at the problems of open circuit of phase current or neutral line current in secondary circuit of current transformer and two-point grounding of circuit under different working conditions, the method are put forward that under abnormal operating conditions such as inrush current and out-of-area fault, the amplitude and phase of the secondary current of different windings, the self-produced zero-sequence current and the external zero-sequence current are compared and analyzed, and the secondary current is correctly connected to the fault recorder, and consummates the inspection work measure ticket and so on. At the same time, the magnetic circuit characteristic of multi-tap transformer is analyzed, and the conclusion that secondary tap does not need short connection is obtained. The integrality of the secondary circuit of the transformer is ensured by the above methods, and the operation reliability of the secondary circuit is improved effectively.
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    Case Analysis and Application of Waste Oil Disposal in Transformer
    REN Qiaolin, ZHANG Yi, ZHANG Wei, CAI Xuan, WU You, LI Zhongling
    Hunan Electric Power    2023, 43 (4): 114-117.   DOI: 10.3969/j.issn.1008-0198.2023.04.017
    Abstract312)      PDF(pc) (1358KB)(231)       Save
    Taking the waste oil treatment of a power supply company as an example, the Meyers index classification and differentiation treatment of oil products are introduced, it not only reduces environmental pollution, but also extends the life cycle of transformer oil, saves the cost of oil treatment and new oil purchase, and promotes the utilization of renewable resources.
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    Method of Distribution Network Voltage Stability Weak Bus Identification Based on Characteristics Curvature
    SUN Jingliao, HU Changhong, CHEN Mengxiang, XIANG Yejun, LIU Jinyuan, ZHU Qiwei
    Hunan Electric Power    2023, 43 (2): 79-84.   DOI: 10.3969/j.issn.1008-0198.2023.02.013
    Abstract305)      PDF(pc) (3021KB)(221)       Save
    In this paper, a method for identifying voltage weak bus in distribution network based on the characteristic curvature is proposed for the determination of voltage stability weak bus. The P-V curve of network bus is generated by the extended power flow method, and the sensitivity index based on the average change rate of the active power-voltage curvature radius is established. K-means clustering is used to classify the sensitivity indexes of distribution network bus, and the evaluation indexes of weak bus are defined to classify and sort the weak. The reactive voltage compensation point is confirmed according to the weakness degree. Simulation experiments based on IEEE 33 node system verify the effectiveness and rationality of the proposed method.
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    Test Analysis of Silicone Rubber Aging Detection Based on Microwave Transmission Method
    LI Huihui, ZHANG Boming, LI Zijin, LI Peng, WU Tian
    Hunan Electric Power    2023, 43 (2): 14-18.   DOI: 10.3969/j.issn.1008-0198.2023.02.003
    Abstract264)      PDF(pc) (3569KB)(208)       Save
    Aiming at the aging problem of shed and sheath of composite insulator, an aging detection method of silicone rubber material based on microwave transmission method is proposed. The artificial accelerated aging test of silicone rubber is carried out, and the microwave nondestructive testing platform is built to carry out the microwave nondestructive testing test of aging silicone rubber. The variation law of transmission parameter S21 of silicone rubber with different aging degrees is analyzed, and the aging detection mechanism of silicone rubber by microwave transmission method was revealed by numerical simulation. The test results show that after the aging of silicone rubber, due to the change of its dielectric properties, the amplitudes of S21 will change,and the aging degree of sillicone rubber can be identified by the value of ΔS21. The research is of great significance to the aging detection of composite insulators.
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    Heater Arrangement Method of 12 kV Switchgear Decondensation Based on Synthesizing Evaluation Function
    XU Junwei, SHU Shengwen, ZHAN Zhaoxuan, BIAN Zhiwen, LIN Yihong
    Hunan Electric Power    2023, 43 (2): 8-13.   DOI: 10.3969/j.issn.1008-0198.2023.02.002
    Abstract235)      PDF(pc) (2748KB)(207)       Save
    In high humidity environment, the switchgear is easy to get damp and form condensation, resulting in a sharp decline in the insulation performance of the electrical equipment in the switchgear. In order to improve the ability of switchgear to cope with humid environment, this paper takes 12 kV high-voltage switchgear as an example to propose a comprehensive evaluation method of heater layout which considers temperature rise level, temperature rise uniformity and dehumidification capacity. Firstly, based on the comprehensive evaluation method of heater layout, the optimal heater layout test is carried out to select the optimal heater layout scheme. Then, the decondensation test is carried out on the basis of the optimal configuration test of the heater to verify the dehumidification performance of the heater layout scheme in the high humidity environment. Finally, combined with the numerical simulation of temperature-fluid multi-physical field, the distribution of temperature and flow field under the condition of heater installation is studied. The results show that the three 50W heater schemes are the best among the two selection strategies. The optimal heater arrangement scheme can completely remove condensation within 4.5h without causing excessive heating of insulation parts.
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    A New Approach Law Sliding Mode Fault Tolerant Control Method for Double Fed Induction Generator Actuator Fault
    LI Shengqing, WEN Yanxi, CHEN Xin
    Hunan Electric Power    2023, 43 (4): 9-15.   DOI: 10.3969/j.issn.1008-0198.2023.04.002
    Abstract181)      PDF(pc) (1809KB)(202)       Save
    In order to overcome the gain-bias fault of the actuator during the operation of the double fed induction generator, a second order non-singular fast terminal sliding mode fault tolerant control is designed by combining the PID sliding surface with the nonlinear non-singular terminal sliding mode surface, and by associating the sliding mode surface function with the control gain using a new adaptive reaching law. Then Lyapunov function is used to prove the stability of the controller. The simulation and experimental results show that compared with the traditional PID and the traditional sliding mode control, the proposed control method weakens chattering, improves the response speed by 49.8%, reduces the steady-state error of the system, and has better fault tolerance.
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