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AC Surface Flashover Characteristics at the Clear Edge of Metallized Polypropylene Film Capacitors

IEEE Transactions on Dielectrics and Electrical Insulation 2025年第3期32卷 1305-1313页

作者： Wang, Zijian Lei, Yiming Yan, Fei Yang, Lin Wang, Zichen Ma, Yanfeng North China Electric Power University Hebei Key Laboratory of Distributed Energy Storage and Micro-Grid Baoding071003 China

Surface flashover significantly affects the insulation performance of metallized film capacitors, and the clear edge is the main area where the surface flashover occurs. An experimental platform is built to study AC surface flashover at the clear edge of metallized polypropylene film capacitors. The effects of interlayer pressure, experiment temperature, clear edge width, square resistanceabsolute humidity and voltage frequency on the AC surface flashover of metallized films are investigated. The results indicate that, the surface flashover voltage and field strength increase with the increase of interlayer pressure in the range of 100 kPa to 800 kPa, and decrease with the increase of experiment temperature in the range of 30 °C to 90 °C;the flashover field strength decreases by 44% and gradually tends to be stable as the clear edge width varies from 0.5 mm to 2.5 mm;the surface flashover voltage and field strength increase by 78% as the square resistance increases from 7.5 Ω/ to 50 Ω/ the surface flashover voltage increases with the increase of absolute humidity in the range of 4 g/m3 to 16 g/m3;the surface flashover voltage and field strength decrease by 4% with the increase of voltage frequency in the range of 50 Hz to 400 Hz. In the design and manufacture of metallized film capacitors, the interlayer pressure of outer films should be appropriately increased;the design of the clear edge width of metallized film capacitors with different square resistance, operating temperatures and voltage frequencies can be selected according to the experimental results of this article. Since the moisture will be removed by heating and vacuumizing in the capacitor manufacturing process, the design of the clear edge width could refer to the experimental results under low humidity. © 2025 IEEE.

关键词： Plastic films

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Improvement Effect of Delay Compensation on High-frequency Resonance Characteristics of MMC-HVDC 9

Improvement Effect of Delay Compensation on High-frequency R...

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9th Asia Conference on power and Electrical Engineering, ACPEE 2024

作者： Zhao, Xiaobin Qin, Hui Feng, Junjie Pan, Zhen Xin, Qingming Yu, Ming Zou, Changyue Huang, Biyue State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid Guang Zhou China Guangxi Power Grid Co. Ltd China Southern Power Grid Co. Ltd. Nanning China

ISBN: (纸本)9798350309638

The control delay is a crucial factor that induces negative damping in the impedance of modular multilevel converter based-high voltage direct current (MMC-HVDC) system at high-frequency range, which potentially lead to high-frequency resonance. Delay compensation is an effective approach to mitigate the impact of control delay. In this paper, the control structure and composition of delay time in MMC-HVDC are first introduced, and the influence of control delay on the impedance characteristics of MMC is analyzed. A method for delay compensation in MMC-HVDC control systems is then proposed. An equivalent impedance model of MMC-HVDC system with delay compensation is established by modifying the reference phase of dq/abc axis transformation. The impact of delay compensation on the impedance characteristics is analyzed. The improvement effect of delay compensation on MMC impedance is influenced by the proportional coefficient of the PI controller in the inner current loop and the compensation time. Finally, the correctness of impedance model and resonance characteristics analysis is verified by impedance scanning and electromagnetic transient simulation. © 2024 IEEE.

关键词： Electromagnetic simulation

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Rapid Identification Method for Potential Risks of Single-phase Reclosing Failure 4

Rapid Identification Method for Potential Risks of Single-ph...

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4th International Conference on Intelligent power and Systems, ICIPS 2024

作者： Tu, Sijia Cai, Xipeng Su, Yinsheng Zhao, Ligang Fan, Lijuan Zhou, Baorong Huang, Guanbiao Zhen, Hongyue China Southern Power Grid Research Institute State Key Laboratory of HVDC Technology Guangzhou China China Southern Grid Power Dispatching Dept. Guangzhou China

ISBN: (纸本)9798331532765

To ensure safe power supply and stable operation of the power grid, single-phase reclosing technology is widely used in domestic and foreign power systems. Except for some power plants, there is no special control strategy or requirement for the single-phase reclosing timing. Multiple circuit breaker failure accidents caused by single-phase reclosing under permanent faults have occurred in the domestic power system, which caused the expandation of accidents and seriously affected the safe and stable operation of the power grid. To avoid the occurrence of such accidents, this article conducts research on a rapid identification method for the potential risk of single-phase reclosing failure. Starting from the mechanism of single-phase reclosing failure, through electro-magnetic transient simulation and actual fault recording analysis, revealing decisive influencing factors of single-phase reclosing failure. Derive the calculation formula for short-circuit current after single-phase reclosing, and propose a risk assessment index, which is risk level of single-phase reclosing failure RANK, for single-phase reclosing failure under the most serious operating conditions. This index describes the probability of circuit breaker failure caused by single-phase reclosing. Based on short-circuit current calculation program in DSP (Digital Simulating Platform), one-click-identification for single-phase reclosing failure risk module is developed. The calculation accuracy is verified by comparing with the results of electro-mechanical and electro-magnetic transient simulation. The module conducts calculation and analysis based on the real operating data of the power grid, providing guiding suggestions for relevant departments in power grid company, effectively supporting the key work of safety risk prevention and control in china's power grid. © 2024 IEEE.

关键词： Risk assessment

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FAULT TRAVELING WAVE CALCULATION FOR DC SYSTEM WITH OVERHEAD-CABLE HYBRID TRANSMISSION LINE

FAULT TRAVELING WAVE CALCULATION FOR DC SYSTEM WITH OVERHEAD...

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2024 china HVDC and power Electronics Annual Meeting of Chinese Society of Electrical Engineering, DCPE 2024

作者： Peng, Faxi Peng, Sui Li, Feng Zhong, Yilin Cao, Runbin Wang, Yanfeng State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid guangzhou China Guangdong Power Grid Co. Ltd Guangzhou China

ISBN: (纸本)9781837242689

Modular multilevel converter (MMC)-based DC systems are suitable for transmitting offshore wind power and usually adopt overhead-cable hybrid transmission lines. After a pole-to-pole DC fault occurs, the traveling wave propagates within the DC system, and the traveling wave processes on the pure overhead line and on the pure cable have been widely researched. However, hybrid transmission lines have different traveling wave characteristics and are less researched. In this paper, a calculation method for the first wave front of a traveling wave is proposed for a symmetrical monopole DC system. Firstly, frequency-dependent models of the overhead line and cable are established. The refraction characteristics at the connection point between the overhead line and the cable and at the connection point between the transmission line and the MMC are analyzed. Combining the traveling wave propagation process, the calculation method of the first wave front reaching the MMC is proposed, and the traveling wave characteristics when the fault occurs on the overhead line and on the cable are discussed. The calculation results are consistent with the simulation results obtained from PSCAD/EMTDC. Thus, the proposed calculation method is correct and accurate, which is useful for fault analysis and protection research on DC systems with hybrid transmission lines. © The Institution of Engineering & Technology 2024.

关键词： Overhead lines

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Multi-Lever EarlyWarning forWind and Photovoltaic power Ramp Events Based on Neural Network and Fuzzy Logic

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Energy Engineering 2024年第11期121卷 3133-3160页

作者： Huan Ma Linlin Ma Zengwei Wang Zhendong Li Yuanzhen Zhu Yutian Liu Power Grid Technology Center State Grid Shandong Electric Power Research InstituteJinan250003China Shandong Electric Power Dispatching and Control Center State Grid Shandong Electric Power CompanyJinan250012China Key Laboratory of Power System Intelligent Dispatch and Control of Ministry of Education Shandong UniversityJinan250061China

With the increasing penetration of renewable energy in power system,renewable energy power ramp events(REPREs),dominated by wind power and photovoltaic power,pose significant threats to the secure and stable operation of power *** paper presents an early warning method for REPREs based on long short-term memory(LSTM)network and fuzzy ***,the warning levels of REPREs are defined by assessing the control costs of various power control ***,the next 4-h power support capability of external grid is estimated by a tie line power predictionmodel,which is constructed based on the ***,considering the risk attitudes of dispatchers,fuzzy rules are employed to address the boundary value attribution of the early warning interval,improving the rationality of power ramp event early *** results demonstrate that the proposed method can generate reasonable early warning levels for REPREs,guiding decision-making for control strategy.

关键词： Early warning machine learning power system security renewable energy power ramp event smart grid

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Detection of Nonlinear Behavior Induced by Hard Limiting in Voltage Source Converters in Wind Farms Based on Higher-order Spectral Analysis

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Journal of Modern power Systems and Clean Energy 2024年第2期12卷 630-645页

作者： Zetian Zheng Shaowei Huang Qiangsheng Bu Chen Shen Jun Yan State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China State Grid Jiangsu Electric Power Co. Ltd.Research InstituteNanjingChina

In recent years, sub-synchronous oscillation accidents caused by wind power integration have received extensive attention. The recorded constant-amplitude waveforms can be induced by either linear or nonlinear oscillation mechanisms. Hence, the nonlinear behavior needs to be distinguished prior to choosing the analysis method. Since the 1960s, the higher-order statistics(HOS) theory has become a powerful tool for the detection of nonlinear behavior(DNB) in production quality control wherein it has mainly been applied to mechanical condition monitoring and fault diagnosis. This study focuses on the hard limiters of the voltage source converter(VSC) control systems in the wind farms and attempts to detect the nonlinear behavior caused by bi-or uni-lateral saturation hard limiting using the HOS analysis. First, the conventional describing function is extended to obtain the detailed frequency domain information on the bi-and uni-lateral saturation hard limiting. Furthermore, the bi-and tri-spectra are introduced as the HOS, which are extended into bi-and tri-coherence spectra to eliminate the effects of the linear parts on the harmonic characteristics of hard limiting in the VSC control system, respectively. The effectiveness of the HOS in the DNB and the classification of the hard-limiting types is proven, and its detailed derivation and estimation procedure is presented. Finally, the quadratic and cubic phase coupling in the signals is illustrated, and the performance of the proposed method is evaluated and discussed.

关键词： Bi-coherence spectrum detection of nonlinear behavior hard limiting higher-order statistics tri-coherence spectrum voltage source converter wind farms.

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A Study on Multi-Objective Cloud-Edge Collaborative Task Scheduling Method for Edge Networks 3

A Study on Multi-Objective Cloud-Edge Collaborative Task Sch...

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3rd International Conference on Cloud Computing, Big Data Application and Software Engineering, CBASE 2024

作者： Yu, Yun Lin, Kequan Huang, Xiang Wu, Wenpeng Zeng, Xichi China Southern Power Grid Company Limited Guangdong Guangzhou510623 China China Southern Power Grid Company Limited Southern Power Grid Digital Grid Research Institute Co.Ltd Guangdong Provincial Key Laboratory of Digital Grid Technology Guangdong Guangzhou510623 China

ISBN: (纸本)9798331506582

As the expansion of new services continues to grow, there may be a shortage of equipment computing, storage and communication resources. At the same time, tasks have the possibility of computation and transmission failure when device resources are limited. Therefore, this paper proposes a research on a multi-objective cloud-edge cooperative task scheduling method for edge networks. The method fully considers the multi-objective optimisation requirements such as task execution efficiency, delay, resource utilisation and energy consumption, and designs an adaptive scheduling strategy by constructing a dynamic model of tasks and resources. The strategy combines genetic algorithms and deep reinforcement learning techniques to achieve reasonable distribution and collaborative processing of tasks between cloud centres and edge nodes. On the basis of the service configuration mechanism, a processing model for microservices is established. By analysing the constraints in task scheduling, priority constraints, capacity constraints and execution time constraints are pointed out. And the scheduling scheme is selected for the task by a multi-criteria decision-making method based on fuzzy logic. The experimental results show that the proposed method has significant advantages in improving the task execution efficiency, reducing the delay and optimising the resource utilisation, which effectively meets the demand of multi-objective optimisation in edge networks, and provides new ideas and references for task scheduling in edge computing environments. © 2024 IEEE.

关键词： Energy utilization

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Operation Cost Optimization Method of Regional Integrated Energy System in Electricity Market Environment Considering Uncertainty

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Journal of Modern power Systems and Clean Energy 2023年第1期11卷 368-380页

作者： Peng Li Fan Zhang Xiyuan Ma Senjing Yao Yuhang Wu Ping Yang Zhuoli Zhao Loi Lei Lai Digital Grid Research Institute of China Southern Power Grid Guangzhou 510663China Guangdong Key Laboratory of Clean Energy Technology South China University of TechnologyGuangzhou 510640China Department of Electrical Engineering School of AutomationGuangdong University of TechnologyGuangzhou 510006China IEEE

In the electricity market environment,the regional integrated energy system(RIES)can reduce the total operation cost by participating in electricity market ***,the RIES will face the risk of load and electricity price uncertainties,which may make its operation cost higher than *** paper proposes a method to optimize the operation cost of the RIES in the electricity market environment considering ***,based on the operation cost structure of the RIES in the electricity market environment,the energy flow relationship of the RIES is analyzed,and the operation cost model of the RIES is ***,the electricity purchase costs of the RIES in the medium-and long-term electricity markets,the spot electricity market,and the retail electricity market are ***,considering the risk of load and electricity price uncertainties,the operation cost optimization model of the RIES is established based on conditional *** it is solved to obtain the operation cost optimization strategy of the *** results show that the proposed operation cost optimization method can reduce the operation cost of high electricity price scenario by optimizing the energy purchase and distribution strategy,constrain the risk of load and electricity price uncertainties,and help balance the risks and benefits.

关键词： Conditional value-at-risk electricity market uncertainty operation cost regional integrated energy system(RIES).

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Energy Scheduling of Wind-Solar Integrated Hydrogen Production System Based on Wind Solar power Prediction 11

Energy Scheduling of Wind-Solar Integrated Hydrogen Producti...

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11th china International Conference on Electricity Distribution, CICED 2024

作者： Luo, Chao Tu, Liang Cai, Haiqing Gu, Haohan Chen, Jiawei Wang, Pengfei Electric Power Research Institute China Southern Power Grid State Key Laboratory of Hvdc Guangzhou China School of Automation Chongqing University Chongqing China

ISBN: (纸本)9798350368345

Hydrogen production from renewable sources is an efficient way to promote renewable sources consumption. In order to suppress the impact of source uncertainty on system scheduling, and improve the system efficiency, a two-stage energy scheduling strategy consisting of two-stage rolling optimization scheduling for a wind-solar integrated hydrogen production system is proposed. In the day-ahead stage, a day-ahead optimization scheduling model is established with the objectives of system operating cost and hydrogen production revenue based on long-term power forecasting. In the intra-day stage, an intra-day rolling optimization scheduling strategy with a day-ahead cost function and energy storage SOC penalty as the basis is established based on short-term power forecasting. Case study verified that the impact of source uncertainty on system energy scheduling can be suppressed with the proposed scheduling strategy, thereby improving system hydrogen production revenue. © 2024 IEEE.

关键词： Windmill

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Neural Network Technology Applied in Fault Detection and Simulation of power Systems 8

Neural Network Technology Applied in Fault Detection and Sim...

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8th International Conference on Electrical, Mechanical and Computer Engineering, ICEMCE 2024

作者： Hong, Zeqi Huang, Libin Hu, Yufeng Guo, Haiping Lu, Yuanhong Hu, Binjiang Zhang, Jingyue Luo, Hui Electric Power Research Institute China Southern Power Grid State Key Laboratory of Hvdc Guangzhou China National Energy Power Grid Technology R and D Centre Guangzhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System Guangzhou China Institute China Southern Power Grid Csg Key Laboratory for Power System Simulation Electric Power Research Guangzhou China

ISBN: (纸本)9798331506230

With the escalating demand for power inspection and equipment maintenance, developing effective algorithms for power system fault detection is crucial for ensuring the safety and stability of power systems. This paper leveragesthe Trellis network, enhanced with an attention module, to significantly improve the Trellis network's capability in recognizing power fault images, thus better addressing fault identification tasks within power systems. Through testing on a self-constructed dataset and comparative experiments with models such as DCNN, RCNN, and DenseNet, the proposed attention mechanismenhanced Trellis network algorithm has demonstrated its effectiveness and superiority in fault detection. © 2024 IEEE.

关键词： power distribution faults

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