Hunan Electric Power

Overview of Control Technologies for Grid-Forming Wind Turbines

WANG Yuwei, WEI Juan, HUANG Sheng, CHEN Daojun, QIU Fengliang

2025, 45(2): 3-12. doi:10.3969/j.issn.1008-0198.2025.02.001

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When traditional grid-following turbines are connected to the power grid on a large scale, issues such as a decline in the short-circuit ratio of the grid, weakened synchronization support capability, and reduced system inertia may arise. Grid-forming wind power generation technologies can mitigate fluctuations in system voltage and frequency, thereby improving the overall safety and stability of power system operation. Firstly, the grid-forming control system frameworks of two typical wind turbines are analyzed: the doubly-fed induction generator (DFIG) and the permanent magnet synchronous generator (PMSG). Based on the most common control strategies, including droop control, virtual synchronous control, and model predictive control, the advantages and disadvantages of these two frameworks are discussed in terms of inertia support capability, overload capacity, and stability. Subsequently, from the perspective of performance improvement, the frequency regulation, voltage control, and robustness of the two models are compared and analyzed. Furthermore, the research progress in control performance enhancement technologies for grid-forming wind turbines are summarized and the future research directions and the key technical challenges that need to be addressed are explored, aiming to provide insights and references for the advancement of grid-forming technologies.

Emergency Collaborative Scheduling Model for Flexible Resources in Distribution Network Under Super Typhoon

HE Jianjun, WU Longteng, WU Jiekang, LI Liang

2025, 45(2): 13-21. doi:10.3969/j.issn.1008-0198.2025.02.002

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Aiming at the problem of large-area power outage in the distribution network caused by super typhoon, a collaborative optimization model of mobile emergency power supply and distributed energy storage is established with the goal of maximizing the normal power supply of important loads and minimizing the power generation cost of mobile emergency power supply. Firstly, considering the spatiotemporal evolution characteristics, the Batts typhoon model is used to calculate the wind speed of each line at each time and then the failure rate of each line is calculated by the line failure rate model. For the lines with fault rates between 0 and 1, the sampling method is used to determine their fault state and derive the set of faulty lines. Combined with the life safety, economy, particularity and the occupied weight, the importance degree of each node load is calculated. The importance degree and the active power of the load are used to determine one objective function, and the other objective function is determined with the goal of minimizing the power generation cost of the mobile emergency power supply. The weight is added to transform the double objective function solution problem into a single objective function solution problem. Finally, the IEEE33 node power distribution system is used to solve the model by using the YALMIP solver CPLEX in the MATLAB toolbox, compare and analyze the results of different schedule schemes.

Power Oscillation Suppression Device and Its Control Method for Distributed Generation System

YANG Ling, LIAO Junhao, HUANG Zehang, HE Qijun, LIAN Chenxi, LI Yibo

2025, 45(2): 22-29. doi:10.3969/j.issn.1008-0198.2025.02.003

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In the distributed generation system composed of new energy sources such as photovoltaic and wind power, the access of constant power load weakens the damping of the system, which may lead to DC bus voltage oscillation and a negative impact on the system stability and the output power quality. The traditional method suppresses voltage oscillation by paralleling large-capacity electrolytic capacitors, but the electrolytic capacitors have defects such as internal loss and large volume, which greatly reduce power density and reliability. In view of the above problems, a new type of power oscillation suppression device and its adaptive control method is proposed. The auxiliary capacitor in the suppression device can effectively absorb and store the oscillation power of the DC bus, and then filter out the voltage harmonics on the DC bus. Compared with the traditional method, the proposed suppression device can effectively filter out single or multiple voltage harmonics and has the advantages of strong applicability and flexible control. Finally, the effectiveness of the proposed method is verified by simulation and experiment.

Research on Multi-Scenario Optimal Scheduling Strategy of Photovoltaic Distribution and Storage System

LANG Yitao, HUANG Meilong, WU Yilin, LIU Xingang, SHEN Feifan

2025, 45(2): 30-35. doi:10.3969/j.issn.1008-0198.2025.02.004

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In order to solve the coupling problem of PV distribution and storage system in multi-scenario scheduling in power market, a multi-scenario optimal scheduling strategy is proposed. Firstly, based on the uncertainty analysis of photovoltaic output, a model of energy storage to stabilize photovoltaic fluctuations is constructed. Secondly, combined with the uncertainty of electricity price, the scheduling strategy of energy storage system to participate in the power market is proposed. Finally, through the optimal scheduling framework of multiple time scales, the charging and discharging plan of the energy storage system is optimized by comprehensively considering the goals of stabilizing photovoltaic fluctuations, electric energy market income and frequency modulation market income. The simulation results show that the proposed strategy can effectively stabilize the fluctuation of PV and maximize the economic benefits in the electric energy and frequency modulation markets. Specifically, the energy storage system not only stabilizes the fluctuation of photovoltaic, but also makes a profit in the electric energy market through the strategy of low storage and high generation, and provides flexible auxiliary services in the frequency modulation market, which significantly improves the economy and stability of the system.

Research on Combustion Deviation Adjustment for Boilers with Side Coal Bunker Based on Wall Temperature Distribution

TAN Jiayu, SU Pan, FANG Tao, ZHOU Xiaoming, GE Wei

2025, 45(2): 36-44. doi:10.3969/j.issn.1008-0198.2025.02.005

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In response to the phenomenon of combustion deviation in opposing-fired boilers equipped with side coal bunkers, experimental studies on the uniform distribution of pulverized coal production and transmission are conducted. Measurements and analyses of primary air volume, pulverized coal flow rate, steam temperature, and wall temperature are carried out, and these findings are cross-validated with theoretical calculations of pulverized coal pipeline resistance. The results identify the uneven distribution of pulverized coal as the primary cause of combustion deviation. Through optimization of pulverized coal distributor opening and the zoning control of over-fire air to regulate wall temperatures, feedback from the visualized wall temperature distribution of heat-absorbing surfaces is used to guide combustion adjustment. The test results show that the distribution of pulverized coal directly affects the temperature distribution on the boiler's side walls, subsequently causing steam temperature deviations. Adjustments to the pulverized coal distributors demonstrate a significant effect in mitigating combustion deviation. After the adjustments, the boiler wall temperature distribution become more uniform, the steam temperature deviation reaches the design specification, and the issue of combustion deviation is significantly improved.

Stability Improvement Method of Multi-Machine Distributed PGCI Under Hybrid Asymmetric Control

WANG Xiaoyuan, NING Zhihao, GAO Jiayuan, QING Mengqi, XIA Tian, TANG Xingzhu, YI Zhijian

2025, 45(2): 45-53. doi:10.3969/j.issn.1008-0198.2025.02.006

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Aiming at the problem of stability improvement under the interaction between multi-machine distributed photovoltaic grid-connected inverter (PGCI) and grid impedance, a stability improvement method of multi-machine distributed PGCI with hybrid asymmetric control architecture is proposed from the d and q axis control loops of PGCI. Firstly, the small-signal impedance model of single-machine system of PGCI considering DC-side voltage fluctuation is constructed. On this basis, considering the influence of line connection impedance and grid impedance, the multi-input and multi-output impedance matrix model of multi-machine distributed PGCI is derived. Secondly, based on the d and q axis impedance characteristics of the GCI, two types of asymmetric impedance reshaping control methods are proposed, which significantly improve the stability of the single-machine grid-connected system. Meanwhile, by analyzing the influence of d-q axis hybrid asymmetric control on multi-machine PGCI, it is shown that d-q axis hybrid asymmetric control can effectively improve the adaptability of PGCI to grid impedance. Finally, the correctness and effectiveness of the proposed control strategy are verified by simulation.

A Method of Improving Grid Impedance Adaptability for Grid-Connected Inverters Considering Asymmetry Effect of PQ Power Loop

WANG Xiaoyuan, NING Zhihao, QING Mengqi, GAO Jiayuan, TANG Xingzhu, WANG Huijuan

2025, 45(2): 54-62. doi:10.3969/j.issn.1008-0198.2025.02.007

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Aiming at the difficulty of grid-connected inverters under PQ power control to adapt to large grid impedance, a method to enhance the grid impedance adaptability of grid-connected inverters considering the asymmetric effect of PQ power loops is proposed. First, by constructing the small-signal control block diagram of the PQ power-controlled grid-connected inverter, the asymmetric effects of the active and reactive power control loops are revealed. On this basis, considering the characteristic that the parameters of the reactive power loop controller are more sensitive to the stability of the grid-connected inverter, an asymmetric design method for the active and reactive power loop controller parameters based on phase compensation is proposed, which significantly expands the adaptability range of the grid-connected inverter to grid impedance and aids in the high penetration rate access of new energy. Finally, the correctness and effectiveness of the proposed control method are verified through simulation and experimentation.

Numerical Simulation Study on Characteristics and Prevention Methods of Ash Deposition in Thermal Power Units Flue

YAN Youyang, CHEN Donglin, YANG Zhan, WANG Shuaihao

2025, 45(2): 63-68. doi:10.3969/j.issn.1008-0198.2025.02.008

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In order to solve the problem of ash deposition in the flue caused by deep peak loading regulation of thermal power units, based on the numerical simulation method of Fluent, the characteristics of fly ash deposition and particle distribution in the flue under different load conditions of thermal power units are studied by constructing a geometric model of the flue structure and a mathematical model of its internal flow. A method to prevent ash deposition in the flue is put forward based on the practical experience of engineering, which is to install a baffle and a high-speed jet nozzle in the flue. The simulation results show that fly ash begins to deposit in the flue when the load of the unit is lower than 80%, and a large number of fly ash deposits in the flue when the load is lower than 40%. The pattern of fly ash particle deposition in different flue structures is as follows: T-shaped flue>right-angle elbow>horizontal flue>gradual flue. And more than 90% of the deposited fly ash particles are larger than 34 μm in diameter. Compared with the existing flue, the flue equipped with the baffle or jet nozzle can reduce the fly ash deposition by 29.16%~58.62% when the unit is operating at 40% of the rated load.

Research on Technological Reformation of Wide-Load Flexible Regulation for Large Francis Hydroelectric Units

TIAN Haiping, WANG Huibin, ZHOU Lihua, REN Zaimei, XU Yongliang

2025, 45(2): 69-73. doi:10.3969/j.issn.1008-0198.2025.02.009

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Aiming at the problem that building new power system requires conventional hydroelectric units to have a wider load operating range and faster regulation ability, taking a large francis turbine of a hydroelectric power plant as the research object, the research on the wide-load flexible regulation reformation is conducted, the operation characteristics of the old hydro turbine in hydroelectric power plant in the past ten years and the existing problems are counted, the reasons why the old unit does not adapt to the new power system and the difficulties in the reformation are analyzed, and the technical scheme of reformation is put forward and verified by model test. The results show that the proposed wide-load reformation scheme is feasible and can provide a reference for the reformation of other old hydroelectric units of the same type.

Optimization Control Strategy for Power Quality in AC-DC Hybrid Microgrid Based on Master-Slave ILC

KANG Qinze, LUO Zhaoxu, LIU Zeyu, MA Fanshuo, XIAO Feng

2025, 45(2): 74-81. doi:10.3969/j.issn.1008-0198.2025.02.010

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Aiming at the power quality problem caused by a large number of nonlinear loads in AC-DC hybrid microgrid, an optimal control strategy for power quality based on master-slave interlinking converter (ILC) is proposed, which adopts a master-slave control mode for multiple ILCs. Among them the ILC with a larger capacity is selected to be the master ILC and works in voltage control mode (VCM), which can make full use of the remaining capacity of the master ILC and absorb a large amount of harmonic components from the AC bus, thus improving the power quality of the microgrid. The slave ILC, operating in current control mode (CCM), can be equated to a smaller virtual conductor in the harmonic domain, which can assist the master ILC to manage negative sequence and harmonics more effectively while suppressing the harmonic resonance that may be generated within the microgrid. At the same time, it can also maintain the stability of the DC bus voltage and more effectively improve the power quality of the AC-DC hybrid microgrid. Finally, the correctness and feasibility of the proposed strategy are verified by MATLAB simulation test.

Selection Method of Load-Bearing Cable Specification of Suspension Crossing Frame

HAN Qiyun, WANG Chao, HUANG Chaoyong, TONG Xin, WANG Shuang, SHEN Yingtong, TANG Bo

2025, 45(2): 82-87. doi:10.3969/j.issn.1008-0198.2025.02.011

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: In the actual construction process of the suspension crossing frame, the specifications of the load-bearing cables are usually selected directly according to the construction experience, which lacks theoretical basis and is easy to cause waste of resources and insufficient safety. A method of selecting the load-bearing cables for the suspension crossing frame based on MATLAB is proposed. According to the motion state equation of the overhead cables, the mechanical properties of the load-bearing cable under the accident state are calculated, and the mathematical model of the safety analysis of the load-bearing cable is established based on MATLAB. Taking the actual project as an example, the established mathematical model is used to calculate the critical value of the load-bearing cables specification that makes the crossing frame meet the requirements of the safety regulations when different wires fall off the grid, and the influence of span change on the comprehensive safety factor of the load-bearing cables is discussed. The research results show that the critical value of the load-bearing cables specification calculated based on the mathematical model is lower than the traditional empirical value, and the calculation conclusion can provide the basis for the selection of the load-bearing cables specification and the formulation of the spanning construction scheme. As the span increases, the comprehensive safety factor of the load-bearing cables decreases in a power function curve, which can provide a reference for the safety design of the suspension crossing frame.

Research on Non-Destructive Preventive Device for Overheating at the Joint of Overhead Lines

WANG Shaoshuai, LI Hang, ZHOU Fugang, ZHAO Pu, LIANG Hongjie, CHEN Bo, DUAN Jiale

2025, 45(2): 88-94. doi:10.3969/j.issn.1008-0198.2025.02.012

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In view of the common heat generation problem at the joints of overhead transmission lines, by measuring the contact resistance, the heating risk of the line after power is transmitted is explored, and the selection of Kelvin double-arm bridge arm resistance parameters and other issues researched. Through control experiments with and without grounding loops, combined with simulation calculations, it is verified that the grounding loop will not affect the measurement results. In the accuracy experiment of preventing heating, the device's balanced score is 88.88%, and the recall rate is 100%, proving that the device has a high accuracy in preventing the heating problem of tension-resistant clamps. In addition, the advantage of the device is that there is no need to remove the wire clamp hardware at the joint during the detection process, thereby avoiding unnecessary damage to the equipment and ensuring the efficiency and safety of the detection process.

Study on Seismic Simulation Shaking Table Test for GIS Composite Bushing and Its Finite Element Analysis

CHEN Yu, GAO Yang, LIU Dongyang, LIU Yuntong, XU Meng

2025, 45(2): 95-103. doi:10.3969/j.issn.1008-0198.2025.02.013

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: Aiming at the seismic performance of a 550 kV GIS composite bushing, the shaking table test and its finite element simulation analysis are conducted on its prototype structure. The shaking table is used to test the dynamic characteristics of the prototype and the response characteristics under the action of artificial seismic wave in different working conditions. The test results show that the dynamic amplification of the prototype structure under the action of artificial seismic wave is significant and the stress concentration at the root of the hollow composite insulator is obvious, which is the weak link in the structure. The finite element analysis software is used to carry out modal analysis and seismic time course analysis on the finite element model of the prototype structure. The analysis results show that the finite element simulation results are highly consistent with the test data of the shaking table, which verifies the accuracy and rationality of the finite element model. In addition, the effects of the support stiffness on the prototype upper structure under the seismic action are further explored. The results show that, with the increase in support stiffness, the acceleration at the top of the prototype first decreases, then increases, and finally decreases, while both the displacement at the top and the strain at the root of the composite insulator first increase and then decrease.

Research on Automatic Mapping Technology of Power Traceability Diagram Based on Directed Acyclic Graph

SUN Qi, CHENG Wei, ZHANG Tianyu, GAO Bin, HE Haoqi

2025, 45(2): 104-109. doi:10.3969/j.issn.1008-0198.2025.02.014

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Aiming at the demand for power traceability mapping, a power traceability automatic mapping technology based on directed acyclic graphs is proposed. The layout algorithm of power grid equipment which is the core method for automatic mapping of power traceability diagrams has been designed based on on power grid equipment and connection relationships data, which mainly includes node layering, node sorting and horizontal coordinate calculation steps. An important power load is taken as an example to carry out power traceability automatic mapping experiment and it is found that the nodes in the graph are evenly distributed, with few intersecting connecting lines. The mapping results are overall reasonable and aesthetically pleasing.

A Three-Dimensional Model Reconstruction Method of Sub‍station Based on Structure-Aware 3D Gaussian Splatting

KANG Wen, DING Yuzhu, DENG Wei, ZHONG Yuming, TANG Jiangqi

2025, 45(2): 110-115. doi:10.3969/j.issn.1008-0198.2025.02.015

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Aiming at the problem that the point cloud complementation technologies or three-dimensional (3D) scanning techniques currently used in 3D model reconstruction of substations rely on high-precision lidar hardware and can only reconstruct moderately sparse and visually inaccurate 3D models, the dual-branch 3D modeling network based on visible light images is proposed, which greatly reduces the dependency on hardware equipment. By fully exploiting the advantages of signed distance fields and 3D Gaussian splatting through mutual geometric supervision and bidirectional guidance, it can efficiently reconstruct texture-rich, dense, and visually high-fidelity substation scenes and their equipment models.

Research on Improved Bubble Sorting Method Based on Spaced Alarm Window in Centralized Control System

ZHOU Hui, DING Yu, CHEN Shengtao, QIN Shiyue, YI Liang

2025, 45(2): 116-121. doi:10.3969/j.issn.1008-0198.2025.02.016

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Aiming at the problem of low correct rate and long time-consuming application of the fixed sequencing mode of alarm window in the centralized control system, an improved bubble sorting method is proposed, which improves the traditional bubble sorting method from the aspects of sorting method and the number of comparisons to enhance the sorting efficiency. Under the premise of ensuring the minimum change in the initial order of the alarm window, the monitoring signal automatically floats to the top layer of the interval after the action, and automatically sinks to the initial position after the return, realizing the automatic dynamic sorting of the alarm window, and effectively improving the efficiency of dynamic capture for the action signal. Finally, by comparing with the fixed sequence method, it is found that the search time of action signals can be saved up to 61.7% after the improved bubble sorting method is adopted, and the correct rate in typical application scenarios is increased to 100%, which verifies the feasibility and effectiveness of the application of the improved bubble sorting method, effectively reduces the work intensity of the monitoring personnel and comprehensively improves the dynamic perception of action signals, so as to achieve the fundamental purpose of improving quality and efficiency.

Infrared Image Segmentation Method of Lightning Arrester Casing Based on Deep Learning and Local Perception Attention Mechanism

WANG Shengqi, CHEN Haibo, YE Jinxiang

2025, 45(2): 122-128. doi:10.3969/j.issn.1008-0198.2025.02.017

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Addressing the issues of low accuracy and susceptibility to false detection in the existing instance segmentation methods for lightning arrester casing, a deep learning-based lightning arrester casing segmentation and detection method is proposed to achieve end-to-end segmentation inference through the classic neural network model UNet. Additionally, the designed local perception attention module efficiently aggregates the channel and spatial information of the lightning arrester casing infrared image, overcoming the impact of infrared background noise and achieving clear edge segmentation effect. The performance of the model Unet in infrared image segmentation and detection of lightning arrester casings is validated through qualitative and quantitative experimental comparisons. The results show that this model offers superior detection and segmentation performance for lightning arrester casings, which is significant for subsequent fault detection, reducing labor costs, and ensuring the safe operation of substation equipment.

Study on Market Trading Mechanism of Virtual Power Plant Adapted to Large Peak-Valley Difference

LI Jichuan, LUO Chaochun, WANG Yu, LIU Xiangbin, GUO Weijia, LIU Dunnan

2025, 45(2): 129-136. doi:10.3969/j.issn.1008-0198.2025.02.018

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With the increasing scale of new energy access, the supply and demand situation of the power system is becoming more and more severe. The trading mechanism for large-scale participation in the market is urgently needed to be established for virtual power plants(VPPs). Against this background, the situation and key issues of VPPs' participation in the market at home and abroad are fully investigated and sorted out, and a trading pattern for VPPs' participation in the medium-and long-term, spot and auxiliary service markets is proposed. Additionally, in order to further utilize the value of the full time-scale flexibility of VPPs, considering the uncertainty of user response, the trading varieties and market model for VPPs to participate in medium-and long-term peaking auxiliary services are constructed. Simulation results demonstrate that this approach can effectively stimulate the flexible adjustment potential of VPPs while mitigating peak shaving pressure arising from the peak-to-valley difference of the system under the high proportion of new energy access.

Collaborative Deployment Method for Communication and Cal‍cula‍tion Resources in Distribution Network Based on Economic-Utility

SUN Haibo, LI Li, LIU Yuxin, LU Shanshan, WU Runze

2025, 45(2): 137-142. doi:10.3969/j.issn.1008-0198.2025.02.019

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In addressing the cross-regional full-life cycle processing flow involving communication and computation in the distribution network, aiming to scientifically assess the resource sufficiency of a given communication and calculation resource cluster for new distribution business flow, and explore the lower limit of the cost demand of communication and calculation resource deployment under the perspective of investment scale, the paper proposes a collaborative deployment method for communication and calculation resources in distribution network based on economic-utility. First, considering the service level, a adequacy evaluation model of multi-domain communication and calculation resources for new distribution service flows is constructed from the perspective of delay. Subsequently, a joint deployment method of communication and calculation resources with an expected resource adequacy constraint is designed and solved with a focus on deployment costs. The simulation results demonstrate that the proposed method achieves reasonable control over deployment costs while ensuring resource adequacy.

Intelligent Design Support System of Power Equipment Selection Based on Vector Retrieval Enhanced Large Lan‍guage Model

ZHU Weidong, HUANG Shuai, HU Qian

2025, 45(2): 143-150. doi:10.3969/j.issn.1008-0198.2025.02.020

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Aiming at the problem that the current power equipment selection design support system is difficult to cope with large-scale and high-complexity selection scenarios, with slow response speed and low design accuracy, a vector retrieval-enhanced intelligent design support system based on large language models is designed. Firstly, a professional knowledge vector database is constructed to encode design knowledge under diverse specific engineering scenarios into high-dimensional vectors and stored in the vector database. Then, grouped query attention and dual-block attention mechanisms are used to optimize the multi-round retrieval process, and the fast retrieval of expertise is achieved by calculating similarities between input requirements and knowledge base vectors. Finally, the multi-round dialogue and context tracking under cue engineering are used to optimize the selection design schemes and enhance system intelligence. The experimental results demonstrate the system performs well in several complex power equipment selection scenarios and can meet the power industry's demand for efficient and intelligent selection design support.

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