30 June 2025, Volume 45 Issue 3

  

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  Transient Stability Assessment of Power System Based on Shift Window Self-attention Swin Transformer

  AN Jun, BIAN Haoyang, ZHOU Yibo

  2025, 45(3): 1-9. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0001-09

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  Current deep learning architectures,particularly Transformer-based models,have demonstrated superior performance in power system transient stability assessment.However,conventional Transformers exhibit insufficient localized feature extraction capability for transient data characteristics.To address this limitation,we propose a Swin Transformer-based transient stability evaluation framework for power systems.By replacing the fixed block-based self-attention mechanism with a hybrid windowing approach that integrates non-overlapping local windows and shifted windows,our method enables synergistic computation of local-global attention patterns.This architecture effectively captures multi-grained features from power system transient data while improving predictive accuracy.Furthermore,our framework incorporates attention mechanism-guided key component identification through adaptive focus allocation, where attention weight distributions are analyzed to establish correlations with system instability modes.This not only enhances model interpretability but also optimizes computational efficiency.Notably,the proposed model exhibits linear computational complexity with respect to feature map dimensions,contrasting with the quadratic complexity inherent in traditional Transformers.Simulation results on the IEEE 10-machine 39-bus system demonstrate that our approach outperforms conventional deep learning and machine learning methods in stability assessment accuracy while maintaining lower computational costs compared to standard Transformer architectures.
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  Wind Turbine Condition Prediction Method Based on OPSO-CNN-Bi-LSTM-Attention

  LIU Hongbo, LI Benxin, ZHANG Peng, WANG Xiao

  2025, 45(3): 10-18. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0010-10

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  To accurately predict the operation status of wind turbines,realize early warning of wind turbine failures, and reduce the maintenance and operation costs,this article proposes an QPSO-CNN-Bi-LSTM-Attention based wind turbine condition prediction method.Firstly,KPCA algorithm is used to extract principal components of wind turbine SCADA monitoring data,and SPE is calculated to construct training set and testing set of wind turbine condition Secondly,the hyperparameters of the QPSO-CNN-Bi-LSTM-Attention model are optimized based on the training set data of the normal and abnormal conditions of the wind turbine,and the SPE of the testing set data is calculated to realize early warning of abnormal state by contrast SPE with its threshold.Finally,the effectiveness and accuracy of the proposed method are verified by an example analysis of the SCADA monitoring data of 1.5 WM wind turbine in a wind farm in Inner Mongolia.Case studies show that the proposed method can better extract the principal components hidden in nonlinear data,and has better prediction performance and stability compared with CNN,LSTM and CNN-LSTM methods in condition prediction of wind turbines.
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  Research on Transient Stability Domain and Stability Improvement Strategy of Direct Driven Wind Power Grid Connected System

  YAN Gangui, ZHANG Haocheng, YUE Lin, YANG Cheng, LI Yongyue

  2025, 45(3): 19-29. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0019-11

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  The wind power grid connected system relies on a phase-locked loop to maintain synchronous operation with the system and achieve decoupling control of active and reactive power.Under large disturbances,the phase-locked loop is highly susceptible to the influence of the grid connection point voltage,leading to wind turbines losing synchronization and disconnecting from the grid.Firstly,the equivalent rotor motion equation of the direct driven wind power grid connected system during the transient period was established,and its synchronization characteristics were characterized and analyzed.Then,by analogy with the power angle stability theory of traditional synchronous generators,analyze the existence of the transient stability equilibrium point of the system under a certain initial state and fault intensity.On this basis,the transient stability domain of active and reactive current injection during power grid faults was comprehensively characterized,and a series of characteristic points in the stability domain were analyzed in detail,providing design basis for different purpose oriented stability control strategies.Finally,a simulation model of a direct driven wind power grid connected system was built on the PSCAD platform,and the transient characteristics of the system under active and reactive current injection at corresponding feature points were quantitatively analyzed.Relevant simulation cases verified the theoretical analysis and the rationality of the proposed transient stability domain.
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  Equipment Selection and Capacity Optimization Configuration of Rooftop Integrated Photovoltaic-storage System Based on Multi-energy Flow Balance Network Modeling 

  HUANG Dawei, CHEN Bingyun, YIN Hang

  2025, 45(3): 30-39. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0030-10

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  Aiming at the problems of equipment selection and capacity configuration of roof integrated photovoltaic storage system,this paper proposes the method of roof photovoltaic equipment selection and capacity optimization configuration based on multi-energy flow balance network model.The equipment and energy flow in the integrated photovoltaic storage system are abstracted as the binary relationship between nodes and branches,and the multi-energy flow balance network modeling is constructed to portray the multi-energy flow coupling relationship and distribution characteristics within the system；through the analysis of the multi-energy flow balance network topology,the graph theoretic method of vertex graph decomposition is applied,and the energy flow correlation matrix between the aggregation-assignment vertexes and the equipment to be selected is formed,and the equipment to be selected is combined in the form of 0-1 variables.The problem of optimizing the capacity allocation of rooftop photovoltaic integrated system is introduced,and an integer linear programming model with comprehensive consideration of economic and energy-saving indexes,as well as equipment selection,capacity allocation and operation constraints,is established.Through simulation,the reasonableness and effectiveness of the proposed modeling method in improving the economy and energy utilization level of building roof integrated photovoltaic storage system are verified.
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  Summary of Key Technologies of Electric Heating Load Participating in Power Grid Regulation 

  ZHANG Liwei, XU Zhixiang, ZHOU Wenting

  2025, 45(3): 40-49. https://doi.org/10.19718/i.issn.1005-2992.2025-03-0040-11

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  The electric heating load can provide a variety of auxiliary services to the power system,which can reduce carbon emissions while improving the stability of the power system.With the deepening of its research at home and abroad,its application scale has gradually expanded.Based on the research results at home and abroad,this paper summarizes the key technologies of electric heating load participating in power grid regulation from four aspects single electric heating model analysis,electric heating load group aggregation mode analysis,electric heating regulation ability evaluation and electric heating participating in power grid auxiliary regulation control mode.Finally,the key technologies of electric heating load participating in power grid regulation are summarized.Combined with the problems faced by the current technology,the three future research directions of improving the modeling accuracy of electric heating load,considering the income problem of the third party and optimizing the scheduling strategy are prospected.
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  Multi-time Scale Scheduling Strategy of Cascade Hydropower System Considering Source-load Coordination and Optimization

  CUI Yang, XU Xiaoqing, YANG Haiwei, ZHAO Yuting

  2025, 45(3): 50-61. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0050-12

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  In order to support the construction of a new power system,the hydropower function has gradually changed from 'power supply'to power supply flexible regulation'.The traditional day-ahead scheduling method of hydropower cannot cope with the short-term new energy fluctuation of power system because it cannot realize the real-time power balance adjustment of hydropower in power system.To this end,this paper proposes a multi-time scale scheduling strategy for cascade hydropower systems considering source-load collaborative optimization to deeply tap the potential of hydropower flexible regulation.Firstly,based on the characteristics of cascade hydropower operation,the problems existing in its participation in real-time power balance regulation of power system are analyzed from two aspects of power and water quantity.Secondly,the synergistic and complementary mechanism of source-side cascade hydropower and load-side flexible regulation resources is analyzed,and the multi-time scale scheduling framework of source-load of cascade water-wind-fire system is constructed.In the real-time stage,the allowable fluctuation range of water level is introduced to limit the fluctuation range of reservoir water level in the real-time regulation stage.Finally, the original model is transformed into a mixed integer linear programming model by using the linearization method,and the example analysis is carried out in the IEEE39 node system.The results show that compared with the traditional day-ahead scheduling method,the proposed method reduces the system operating cost by 9.3%，increases the wind power consumption by 1.52%，and reduces the system carbon emission by 4.85%.It can help the system to achieve safe,economic and low-carbon operation.
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  Inverter Dual-mode Operation Control Strategy Based on Improved Droop Controll

  LI Shanshou, WANG Siwen, YE Wei, HUANG Meichu, XIE Chenlei

  2025, 45(3): 62-69. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0062-08

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  In order to solve the problems of grid current impact and output power overshoot caused by the switching between the two working modes of remote island and grid connection of the microgrid inverter, an improved dual- mode unified control strategy was designed on the basis of droop control, drawing on the control of virtual synchronous machine, adding an inertia adjustment unit in the active droop control, and adding an integral link in the active and reactive droop control at the same time. While suppressing the impact of the incoming current, the system power is stably output at the rated value, and combined with the active pre- synchronization control of the grid, the smooth switching of the inverter's off/on- grid mode is realized. The simulation results verify the effectiveness of the control strategy proposed in this paper, and the inverter can achieve stable control of output power in both off- grid and grid- connected modes, and there is no voltage and current impulse when the mode is switched.
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  Current-limited SSSC Control Strategy Considering Multistage Transient Stability of Wind-thermal Binding System After Failure

  LI Juan, WANG Yan

  2025, 45(3): 70-80. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0070-11

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  In this paper, on the basis of explaining the working principle of the current- limiting SSSC, the SSSC is adopted to strengthen the electrical connection between the sending end and the receiving end of the wind- thermal binding system. Based on the equivalent external characteristics of the doubly fed induction generator, a power model is established for the wind- thermal binding system with the current- limiting SSSC in normal operation, fault periods, and after faults. The relationship between the limiting resistance of the current- limiting SSSC and the defined initial swing transient stability margin is derived through the area- equal principle. A strategy is proposed to ensure the stability of the initial swing during fault periods by injecting the limiting resistance. The influence of wind power active power recovery and the compensation degree of the SSSC on the electromagnetic power after the fault removal is analyzed, and a control strategy is proposed to suppress the power oscillation after the first swing by changing the compensation degree of the SSSC according to the change of the angle of attack of the steam turbine and the recovery of wind power in each odd and even swing process. The simulation results in Simulink show that the control strategy of the current- limiting SSSC in different swing periods can effectively improve the transient stability of the wind- thermal binding system.
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  Study of Thee-level High-gain Split-source Flying Capacitor Two-stage Matrix Converter and Its Modulation Strategy

  WANG Rutian, HAN Longjie, Yu Yang

  2025, 45(3): 81-89. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0081-09

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  In order to address the issue of inadequate voltage gain in conventional two- stage matrix converters, this paper puts forth a novel three- level high gain split- source flying capacitor two- stage matrix converter (TL- HGSSFC- TSMC) and undertakes a comprehensive investigation of its modulation strategy. The converter integrates the functionality of a two- stage matrix converter, a novel high- gain split- source network, and a three- level flying capacitor inverter, with the objective of enhancing the voltage gain and the quality of the output waveform of the converter. The rectifier stage modulation employs a zero- free vector modulation strategy, and the operating principles of the high- gain split- source network and the three- level flying capacitor topology are systematically analyzed. The flying capacitor inverter stage employs the enhanced space vector pulse width modulation (SVPWM) method based on phase- shifted carrier, a technique that effectively addresses the flying capacitor voltage unbalance issue. Subsequent to the theoretical underpinnings, a simulation verification procedure was executed using Matlab/Simulink. The outcomes demonstrate that the proposed converter substantially enhances the voltage transfer ratio and attains a three- level output when contrasted with the conventional topology.
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  Robust and Flexible Regulation of Multi-Energy Coupling Systems with Consideration of Wind and Solar Uncertainty

  PAN Chao, LAN Bing, LI Hao

  2025, 45(3): 90-99. https://doi.org/10.19718/j.issn.1005-2992.2025-03-0090-10

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  To mitigate the impact of renewable energy fluctuations on the power grid and achieve a balance between flexibility and toughness in the multi- energy coupling system, a robust and flexible regulation strategy for the multi- energy coupling system considering wind and solar uncertainty is proposed. The strategy involves tapping into the flexibility resources of sources, storage, and loads, determining the day- ahead plan based on the linkage of these flexible resources, and conducting robust intra- day regulation considering wind and solar fluctuations. Finally, a simulation analysis is conducted on a regional system in Northeast China, comprehensively evaluating the effectiveness of the operation plan from the economic cost, peak shaving and valley filling, wind and solar absorption and low carbon emissions. The results show that the robust and flexible regulation strategy for the multi- energy coupling system considering wind and solar uncertainty can effectively enhance its flexibility and toughness. When the wind and solar conservation parameter is 10/5 and the wind and solar uncertainty parameter is?σw,t/σv,tσw,t?/σv,t??, the wind and solar absorption rate is increased by 1.57%, the economic cost is saved by 53.90%, the peak shaving and valley filling is reduced by 0.36%, and the carbon emission of low- carbon units is reduced by 15.57%.
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  Researchon the Coordinated Control Strategy of AGC for Wind and Solar Hybrid Energy Stations Based on Photovoltaic Compensation

  XIA Minghui, HAN Wei, SHE Chao, ZHAO Xinyi, LIAN Yucheng, LIN Zhongwei, SONG Yifan, ZHOU Jiawei

  2025, 45(3): 100-109. https://doi.org/10.19718/j.issn.1005- 2992.2025- 03- 0100- 10

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  To address the issues of large active power fluctuations and low tracking accuracy in traditional wind and solar hybrid energy stations, leveraging the fast response speed and low adjustment cost of photovoltaic (PV) systems, this paper proposes an optimized control strategy based on real- time PV compensation. Firstly, the maximum achievable active power of the station is calculated. An Adaptive Exponential Moving Average (AEMA) algorithm is employed to process the theoretical power, enhancing the confidence level of the maximum achievable active power and reducing the fluctuation in the station's active power. Secondly, optimize the instruction computing module. By controlling the active power of the PV subsystem, and based on the time- misalignment and stepwise adjustment of wind and PV commands, the power deviation required for the tracking and scheduling commands of the wind and solar hybrid energy station is compensated in real- time. Finally, The strategy was tested on- site at wind and solar hybrid power stations. The results show that the proposed control strategy improves the station's regulation accuracy and reduces active power fluctuations compared to conventional strategies, and has broad application prospects.
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  Power Margin Adjustment of Wind-light-fire-ammonia Combined System Considering Waste Heat Recovery of Ammonia Production Bi-level Optimal Scheduling

  ZHANG Hong, ZHANG Lianshuai, LI Yazhou, ZHANG Zexi, LU Chunxiao, XING Dacheng

  2025, 45(3): 110-120. https://doi.org/10.19718/j.issn. 1005-2992.2025-03-0110-09

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  With the full integration of wind and solar renewable energy,the increase of the total amount of wind and solar energy and the problem of insufficient system power regulation margin are becoming more and more serious.In order to realize the economic utilization of renewable energy and the stable operation of energy system,it is urgent to solve these problems,this paper proposes a bi- level optimal scheduling strategy for power margin adjustment of wind- solar- thermal- ammonia combined system considering ammonia waste heat recovery. Firstly,the overall power regulation margin model of thermal power unit- ammonia energy system and its waste heat recovery is established. Then,considering the influence of ambient temperature on the waste heat recovery efficiency of ammonia energy system,a bi- level optimal scheduling model is constructed with the maximum power regulation margin of wind- solar- fire- ammonia combined system as the upper objective and the minimum total cost as the lower objective.Finally,the simulation results show that the proposed optimal scheduling method can improve the power regulation margin of the combined system and promote the consumption of renewable energy.