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Deep Learning-Based Secure Transmission Strategy with Sensor-Transmission-Computing Linkage for power Internet of Things

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Computers, Materials & Continua 2024年第3期78卷 3267-3282页

作者： Bin Li Linghui Kong Xiangyi Zhang Bochuo Kou Hui Yu Bowen Liu state grid Beijing Urban District power supply company Beijing100034China

The automatic collection of power grid situation information, along with real-time multimedia interaction between the front and back ends during the accident handling process, has generated a massive amount of power grid data. While wireless communication offers a convenient channel for grid terminal access and data transmission, it is important to note that the bandwidth of wireless communication is limited. Additionally, the broadcast nature of wireless transmission raises concerns about the potential for unauthorized eavesdropping during data transmission. To address these challenges and achieve reliable, secure, and real-time transmission of power grid data, an intelligent security transmission strategy with sensor-transmission-computing linkage is proposed in this paper. The primary objective of this strategy is to maximize the confidentiality capacity of the system. To tackle this, an optimization problem is formulated, taking into consideration interruption probability and interception probability as constraints. To efficiently solve this optimization problem, a low-complexity algorithm rooted in deep reinforcement learning is designed, which aims to derive a suboptimal solution for the problem at hand. Ultimately, through simulation results, the validity of the proposed strategy in guaranteed communication security, stability, and timeliness is substantiated. The results confirm that the proposed intelligent security transmission strategy significantly contributes to the safeguarding of communication integrity, system stability, and timely data delivery.

关键词： Secure transmission deep learning power Internet of Things sensor-transmission-computing

A Simple and Effective Surface Defect Detection Method of power Line Insulators for Difficult Small Objects

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Computers, Materials & Continua 2024年第4期79卷 373-390页

作者： Xiao Lu Chengling Jiang Zhoujun Ma Haitao Li Yuexin Liu state grid Jiangsu Electric power Co. Ltd.Nanjing210024China state grid Changzhou power supply company Changzhou213003China

Insulator defect detection plays a vital role in maintaining the secure operation of power systems.To address the issues of the difficulty of detecting small objects and missing objects due to the small scale,variable scale,and fuzzy edge morphology of insulator defects,we construct an insulator dataset with 1600 samples containing flashovers and breakages.Then a simple and effective surface defect detection method of power line insulators for difficult small objects is proposed.Firstly,a high-resolution featuremap is introduced and a small object prediction layer is added so that the model can detect tiny objects.Secondly,a simplified adaptive spatial feature fusion(SASFF)module is introduced to perform cross-scale spatial fusion to improve adaptability to variable multi-scale features.Finally,we propose an enhanced deformable attention mechanism(EDAM)module.By integrating a gating activation function,the model is further inspired to learn a small number of critical sampling points near reference points.And the module can improve the perception of object morphology.The experimental results indicate that concerning the dataset of flashover and breakage defects,this method improves the performance of YOLOv5,YOLOv7,and YOLOv8.In practical application,it can simply and effectively improve the precision of power line insulator defect detection and reduce missing detection for difficult small objects.

关键词： Insulator defect detection small object power line deformable attention mechanism

Capacitor Voltage Imbalance Mechanism and Balancing Control of MMC When Riding Through PTG Fault

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CSEE Journal of power and Energy Systems 2024年第2期10卷 778-785页

作者： Zhen He Maozeng Lu Lijun Hang Pingliang Zeng Yanhua Liu Hangzhou Dianzi University Hangzhou 310018China Shandong University of Technology Zibo 255000China state grid Hangzhou power supply company State GridHangzhou 310000China

Modular multilevel converter (MMC) based fault ride through (FRT) control is a promising solution to deal with the pole-to-ground (PTG) fault in high voltage direct current (HVDC) system. However, when MMC switches to the FRT control, capacitor voltage imbalance between upper and lower arms will occur, resulting in the deterioration of FRT performance. This letter provides a comprehensive analysis for the imbalance issue from the perspective of fundamental frequency circulating current (FFCC). It is found the imbalance during FRT stage will not expand continuously, but converge to a certain value gradually. The specific imbalance degree is closely associated with the amplitude of FFCC. In order to solve the imbalance issue, an open-loop balancing control is proposed. By introducing a fundamental frequency feedforward item to the inherent circulating current control, the proposed method can not only balance the capacitor voltages, but also minimize the amplitude of FFCC, and consequently the power loss of MMC during FRT process can be reduced. Finally, simulation results of PSCAD/ EMTDC verify the validity of theoretical analysis.

关键词： Balancing control capacitor voltage imbalance FFCC FRT control HVDC system PTG fault

Research on Transmission Line Tower Tilting and Foundation state Monitoring Technology Based onMulti-Sensor Cooperative Detection and Correction

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Energy Engineering 2024年第1期121卷 169-185页

作者： Guangxin Zhang Minghui Liu Shichao Cheng Minzhen Wang Changshun Zhao Hongdan Zhao Gaiming Zhong College of Science and Technology(CST) Ningbo UniversityNingbo315000China Dadong power supply company State Grid Liaoning Electric Power Co.Ltd.Dandong118000China Dalian power supply company State Grid Liaoning Electric Power Co.Ltd.Dalian116000China Yanbian power supply company State Grid Jilin Electric Power Co.Ltd.Yanji133000China Liaoyuan power supply company State Grid Jilin Electric Power Co.Ltd.Liaoyuan136200China

The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the building to collapse.Many small changes caused the tower’s collapse,but the early staff often could not intuitively notice the changes in the tower’s state.In the current tower online monitoring system,terminal equipment often needs to replace batteries frequently due to premature exhaustion of power.According to the need for real-time measurement of power line tower,this research designed a real-time monitoring device monitoring the transmission tower attitude tilting and foundation state based on the inertial sensor,the acceleration of 3 axis inertial sensor and angular velocity raw data to pole average filtering pre-processing,and then through the complementary filtering algorithm for comprehensive calculation of tilt angle,the system meets the demand for inclined online monitoring of power line poles and towers regarding measurement accuracy,with low cost and power consumption.The optimization multi-sensor cooperative detection and correction measured tilt angle result relative accuracy can reach 1.03%,which has specific promotion and application value since the system has the advantages of unattended and efficient calculation.

关键词： Transmission line tower tilting multi-sensor foundation state monitoring collaborative detection

Study on the influence of mechanism dispersion on transient recovery voltage distribution of modular DC vacuum circuit breakers

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High Voltage 2024年第2期9卷 346-355页

作者： Chongyang Huang Yongshuai Yin Shuxin Liu Hanwen Du Zengyu Shan Yundong Cao Shurui Yang Key Laboratory of Special Electric Machines and High Voltage Apparatus in the Ministry of Education Shenyang University of TechnologyShenyangChina Shenyang power supply company of state grid Liaoning Electric power Co. LtdShenyangChina Chifeng power supply company of state grid Mongolia Electric power Co. LtdChifengChina

A simulation analysis and an experiment are carried out to investigate how the gap difference between the breaks of a direct current vacuum circuit breakers with multi-breaks(MB-DC VCB)caused by the mechanism dispersion of the breaker influences the distribution of TRV among the breaks.An interruption model of MB-DC VCB,combining the continuous transition model,is established to analyse the rising rate of transient recovery voltage and the dielectric strength recovery speed of the breaks for MB-DC VCB under different gap difference conditions.Based on the experimental platform of dual break DC vacuum circuit breaker breaking,the correctness of the simulation model is verified on a DC VCB with the double-breaks interruption experimental platform.Moreover,a model is applied to the non-synchronous interruption simulation of a DC VCB with three-breaks.The relationship between the TRVs of the breaks under different gap difference conditions is analysed using the comparative analysis method,obtaining the maximum gap difference at the moment of breaking failure.The results of this study show that large-gap breaks have a higher TRV than small-gap breaks(the fracture of the action delay module),with double fractures reaching 1.4 times and triple fractures reaching a maximum of 1.52 times;the ability of small-gap breaks to withstand TRV is weak,giving rise to re-breakdown or even interruption failure;as the number of fractures increases,the maximum gap difference also increases.Improving the synchronous interruption ability of the MB-DC VCB is conducive to improving the interruption performance and interruption success rate of this type of a circuit breaker.

关键词： TRV transient distribution

A Novel Defender-Attacker-Defender Model for Resilient Distributed Generator Planning with Network Reconfiguration and Demand Response

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Energy Engineering 2024年第5期121卷 1223-1243页

作者： Wenlu Ji Teng Tu Nan Ma Nanjing power supply company State Grid Jiangsu Electric Power Co.Ltd.Nanjing210019China

To improve the resilience of a distribution system against extreme weather,a fuel-based distributed generator(DG)allocation model is proposed in this study.In this model,the DGs are placed at the planning stage.When an extreme event occurs,the controllable generators form temporary microgrids(MGs)to restore the load maximally.Simultaneously,a demand response program(DRP)mitigates the imbalance between the power supply and demand during extreme events.To cope with the fault uncertainty,a robust optimization(RO)method is applied to reduce the long-term investment and short-term operation costs.The optimization is formulated as a tri-level defenderattacker-defender(DAD)framework.At the first level,decision-makers work out the DG allocation scheme;at the second level,the attacker finds the optimal attack strategy with maximum damage;and at the third level,restoration measures,namely distribution network reconfiguration(DNR)and demand response are performed.The problem is solved by the nested column and constraint generation(NC&CG)method and the model is validated using an IEEE 33-node system.Case studies validate the effectiveness and superiority of the proposed model according to the enhanced resilience and reduced cost.

关键词： Distribution system resilience defender-attacker-defender distributed generator demand response microgrids formation

Defect Detection in c-Si Photovoltaic Modules via Transient Thermography and Deconvolution Optimization

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Chinese Journal of Electrical Engineering 2024年第1期10卷 3-11页

作者： Zekai Shen Hanqi Dai Hongwei Mei Yanxin Tu Liming Wang state grid Hangzhou power supply company State Grid Zhejiang Electric Power Co.Ltd.Hangzhou 310000China Huairou power supply Branch State Grid Beijing Electric Power Co.Ltd.Beijing 101400China Tsinghua Shenzhen International Graduate School Tsinghua UniversityShenzhen 518055China

Defects may occur in photovoltaic(PV)modules during production and long-term use,thereby threatening the safe operation of PV power stations.Transient thermography is a promising defect detection technology;however,its detection is limited by transverse thermal diffusion.This phenomenon is particularly noteworthy in the panel glasses of PV modules.A dynamic thermography testing method via transient thermography and Wiener filtering deconvolution optimization is proposed.Based on the time-varying characteristics of the point spread function,the selection rules of the first-order difference image for deconvolution are given.Samples with a broken grid and artificial cracks were tested to validate the performance of the optimization method.Compared with the feature images generated by traditional methods,the proposed method significantly improved the visual quality.Quantitative defect size detection can be realized by combining the deconvolution optimization method with adaptive threshold segmentation.For the same batch of PV products,the detection error could be controlled to within 10%.

关键词： Photovoltaic module transient thermography point spread function deconvolution optimization quantitative detection

Stress Concentration Effect in Interface Between Conductor and Epoxy Resin in Coaxial Components of power Equipment

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CSEE Journal of power and Energy Systems 2024年第1期10卷 412-420页

作者： Chuang Wang Kang Lei Qing Sun Hui Li Jiawei Zhang Lang Zhao Zongren Peng School of Electrical Engineering Xi’an University of TechnologyXi’an 710054China Xi’an power supply company State Grid Shaanxi Electric Power CompanyXi’an 710032China state Key Laboratory of Electrical Insulation and power Equipment Xi’an Jiaotong UniversityXi’an 710049China

The spacer used in gas insulated switchgear(GIS)plays a vital role in its safe operation.The mismatch of mechanical properties between conductor and insulating material in spacers results in stress concentration at the interface between them.During a hydrostatic test,mechanical damages are often initiated from the interface.In this paper,the stress between aluminum conductors and epoxy resin is studied by using a simplified coaxial structure specimen.The measurement system and finite element simulation are used to explore the generation of stress and strain during curing and shrinkage.The real-time measurement of strain at the interface shows that the residual strain in the entire process is primarily generated during the cooling stage.Consequently,the temperature and stress/strain distribution at the interface during the cooling stage are further studied,and combined with experiments and simulations.The consistency between the finite element simulation and the experimental measurement results verifies the validity of the simulation method used.The results show that the maximum of the first principal stress generated during the cooling stage of the production process is concentrated on the upper and lower edges of the interface which is critical to the impact of the production quality of the spacer.

关键词： Epoxy resin GIS interface stress/strain distribution

Flexible Load Participation in Peaking Shaving and Valley Filling Based on Dynamic Price Incentives

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Energy Engineering 2024年第2期121卷 523-540页

作者： Lifeng Wang Jing Yu Wenlu Ji Nanjing power supply company Nanjing210019China state grid Jiangsu Electric power Co. Ltd.Nanjing211103China

Considering the widening of the peak-valley difference in the power grid and the difficulty of the existing fixed time-of-use electricity price mechanism in meeting the energy demand of heterogeneous users at various moments or motivating users,the design of a reasonable dynamic pricing mechanism to actively engage users in demand response becomes imperative for power grid companies.For this purpose,a power grid-flexible load bilevel model is constructed based on dynamic pricing,where the leader is the dispatching center and the lower-level flexible load acts as the follower.Initially,an upper-level day-ahead dispatching model for the power grid is established,considering the lowest power grid dispatching cost as the objective function and incorporating the power grid-side constraints.Then,the lower level comprehensively considers the load characteristics of industrial load,energy storage,and data centers,and then establishes a lower-level flexible load operation model with the lowest user power-consuming cost as the objective function.Finally,the proposed method is validated using the IEEE-118 system,and the findings indicate that the dynamic pricing mechanism for peaking shaving and valley filling can effectively guide users to respond actively,thereby reducing the peak-valley difference and decreasing users’purchasing costs.

关键词： Demand response fixed time-of-use electricity price mechanism dynamic price incentives mechanism bi-level model flexible load