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Accumulation characteristics of precipitation static on rotating wind turbine blades and its influence on the lightning attachment characteristics

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High Voltage 2024年第6期9卷 1270-1279页

作者： Lingfeng Jiang Zhenglong Jiang Jiazheng Lu Dexiong Hu Pengkang Xie Xiaoqi Huang State Key Laboratory of Disaster Prevention&Reduction for Power Grid(Changsha University of Science&Technology) ChangshaChina State Key Laboratory of Disaster Prevention&Reduction for Power Grid(State Grid Hunan Electric Power Corporation Disaster Prevention and Reduction Center) ChangshaChina School of Electrical and Information Engineering Hunan UniversityChangshaChina State Grid Hunan Electric Power Company Limited Hydropower Company ChangshaChina

The linear velocity at the tip of large wind turbine blades can reach 100 m/s,generating static electricity through friction with airborne ***,the accumulation characteristics of precipitation static on the blade surface and its impact on the lightning attachment characteristics are rarely *** authors constructed a platform for measuring charges on rotating wind turbine blades and employed the electrostatic probe method to obtain the accumulation characteristics of surface charges under different environmental *** experimental results show that positive charges accumu-late on the blade surfaces,peaking at 0.69μC/m2 under experimental *** charge density is positively correlated with airborne particle concentration and blade rotation speed,while it is negatively correlated with relative air ***,the authors developed a model of the electric field distribution on wind turbine blades considering the effects of precipitation *** results indicate that the elec-trostatic field induced by precipitation static weakens the field strength in the vicinity of receptors,reaching a minimum of only 38%of the original strength,thereby increasing the probability of lightning protection *** findings provide an effective supple-ment to the lightning attachment mechanism of rotating wind turbine blades.

关键词： rotating blade charges

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Study on the Direct Current Temperature Rise Law of Contact Wire and Supporting Cable Under Icing Conditions 6

Study on the Direct Current Temperature Rise Law of Contact ...

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6th International Conference on Energy, power and grid, ICEPG 2024

作者： Li, Bo Huang, Linwei Luo, Jing Li, Ziang Zhou, Shiyang Fang, Zuo Hunan Disaster Prevention Technology Co. Ltd. State Key Laboratory of Disaster Prevention and Reduction for Power Grid Changsha China State grid Hunan Disaster prevention and reduction center State Key Laboratory of Disaster Prevention and Reduction for Power Grid Changsha China

ISBN: (纸本)9798350377798

In winter, the overhead contact line (OCL) of rail transit systems is highly susceptible to icing during periods without train traffic, leading to train suspensions and passenger delays. Currently, de-icing of overhead lines is mainly performed manually, as the current-based de-icing techniques used in power systems cannot be directly applied to rail transit OCLs. Therefore, this paper analyzes the temperature rise mechanism during the OCL de-icing process and establishes a thermal balance equation for OCL de-icing. After denoising with MATLAB, curve fitting and simulation are conducted. Finally, an artificial climate chamber is used to simulate the temperature rise test during the de-icing process, and the current-temperature rise curve obtained during the OCL de-icing process is validated. The study shows that the temperature rise process of the OCL and load-bearing cable during direct current (DC) de-icing is positively correlated with DC current and negatively correlated with ice thickness and external environmental conditions. Under the same current, the temperature rise of the rail transit OCL and load-bearing cable is smaller compared to power transmission lines, and the simulated temperature rise curve strongly correlates with the experimentally derived curve. The research results provide theoretical guidance for OCL de-icing. © 2024 IEEE.

关键词： Light rail transit

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Effect of Grain Size Disorder on the Performance of ZnO Varistors Based on Voronoi Network and Finite Element Simulation 11

Effect of Grain Size Disorder on the Performance of ZnO Vari...

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11th International Forum on Electrical Engineering and Automation, IFEEA 2024

作者： Fu, Zhiyao Liao, Zemin Jiang, Zhenglong Wang, Bowen Disaster Prevention and Reduction Center of State Grid Hunan Electric Power Co. State Key Laboratory of Disaster Prevention & Reduction for Power Grid Changsha China

ISBN: (纸本)9798331516611

The construction of a reasonable numerical simulation model is of great significance for understanding and predicting the current distribution inside the ZnO varistor ceramics, which can provide the theoretical basis and guidance for improving the through-current performance of ZnO varistors. In addition to the electric field effect, the ZnO varistors involve the multi-physical field coupling problems of thermal field and force field when they are subjected to current impulses. This paper establishes a finite element multi-physical field model of ZnO varistor by combining Voronoi network and finite element method, and analyzes the effects of grain size disorder on the current distribution of ZnO varistor in different current regions and the temperatures and stresses under 2ms square wave current. © 2024 IEEE.

关键词： Grain size and shape

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Distributed Photovoltaic Output Prediction Using Machine Learning and Numerical Model Combined Method 1

Distributed Photovoltaic Output Prediction Using Machine Lea...

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2024 1st International Conference on Smart grids and power Systems, ICSGPS 2024

作者： Wang, Lei Kang, Wenjun Feng, Tao Li, Li State Key Laboratory of Disaster Prevention & Reduction for Power Grid Changsha China

In recent years, distributed photostatic (PV) has developed rapidly. Accurate prediction of distributed PV output can improve the reliable, efficient and economical grid-connected operation of distributed PV, and enhance the reliability of power supply. In this study, we first collected the datasets of distributed PV output and centralized PV station output in Dongan County, Yongzhou City, Hunan Province. Then, we analyzed the relationship between distributed PV station output and centralized PV output under different weather conditions, and constructed the centralized PV output prediction curve by combining machine learning and numerical prediction model, and finally obtained the distributed PV output prediction of the whole county. The results show that the correlation coefficient changes between the output of distributed PV stations and that of centralized PV stations under different weather scenarios (sunny, cloudy, etc.), but they all show a good consistency (the correlation coefficient of more than 0.6 accounts for more than 95% of the PV stations), indicating that the output change of centralized PV stations in one county can be used to characterize the output change of distributed stations. The distributed PV output prediction model built by LSTM and numerical model combined method has achieved a prediction accuracy of 90.4% for a single station and 94.31% for the whole county within 24 hours, both of which are 4% 5% higher than the requirements of national standards. The model can be further extended to forecast the distributed PV output of the whole province. © 2024 Published under licence by IOP Publishing Ltd.

关键词： Numerical models

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Research on Lightning Protection Performance and Parameter Selection of Lightning Protection Insulator for ±500kV DC Transmission Line 8

Research on Lightning Protection Performance and Parameter S...

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8th International Conference on Smart grid and Smart Cities, ICSGSC 2024

作者： Shi, Xin Jiang, Zhenglong Fu, Zhiyao Xie, Pengkang Wang, Bowen Hu, Jianping State Grid Hunan electric Power State Key laboratory of Disaster Prevention and Reduction for Power Grid Changsha China

ISBN: (纸本)9798350377408

The lightning fault of the ± 500kV DC transmission line constitutes a significant proportion, and the situation regarding lightning protection is severe. Currently, there is limited research on the lightning characteristics of ± 500kV DC transmission lines after installing arresters or lightning protection insulators, as well as their performance with different parameters. This study takes the ± 500kV Jiangcheng DC transmission line as an example to calculate the maximum shielding failure current using the electrical geometry method. An electromagnetic transient simulation model of the transmission line is established to analyze and calculate the action characteristics of lightning protection insulators under shielding failure conditions. Additionally, this study calculates and analyzes the influence of ground inclination angle and parameter selection for lightning protection insulators on their shielding failure performance. The findings presented in this paper can serve as a reference for selecting appropriate parameters for lightning protection insulators. © 2024 IEEE.

关键词： Lightning arresters

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Security distance analysis of active distribution network considering energy hub demand response

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Global Energy Interconnection 2025年第1期8卷 160-173页

作者： Rui Ma Qi Zhou Shengyang Liu Qin Yan Mo Shi State Key Laboratory of Disaster Prevention&Reduction for Power Grid Changsha University of Science&TechnologyChangsha 410114PR China Electric Power Research Institute of Guangdong Power Grid Co. LtdGuangdong Provincial Key Laboratory of Electric Power Equipment ReliabilityGuangzhou 510080PR China

This study proposes a method for analyzing the security distance of an Active Distribution Network(ADN)by incorporating the demand response of an Energy Hub(EH).Taking into account the impact of stochastic wind-solar power and flexible loads on the EH,an interactive power model was developed to represent the EH’s operation under these ***,an ADN security distance model,integrating an EH with flexible loads,was constructed to evaluate the effect of flexible load variations on the ADN’s security *** considering scenarios such as air conditioning(AC)load reduction and base station(BS)load transfer,the security distances of phases A,B,and C increased by 17.1%,17.2%,and 17.7%,***,a multi-objective optimal power flow model was formulated and solved using the Forward-Backward power Flow Algorithm,the NSGA-II multi-objective optimization algo-rithm,and the maximum satisfaction *** simulation results of the IEEE33 node system example demonstrate that after opti-mization,the total energy cost for one day is reduced by 0.026%,and the total security distance limit of the ADN’s three phases is improved by 0.1 *** method effectively enhances the security distance,facilitates BS load transfer and AC load reduction,and contributes to the energy-saving,economical,and safe operation of the power system.

关键词： Active distribution network Energy hub Security distance Base station load Air-conditioning load

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Enhanced properties of stone coal-based composite phase change materials for thermal energy storage

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 206-215页

作者： Baoshan Xie Huan Ma Chuanchang Li Jian Chen Key Laboratory of Renewable Energy Electric-Technology of Hunan Province School of Energy and Power EngineeringChangsha University of Science and TechnologyChangsha 410114China State Key Laboratory of Disaster Prevention and Reduction for Power Grid Changsha University of Science and TechnologyChangsha 410114China

Phase change materials (PCMs) can be incorporated with low-cost minerals to synthesize composites for thermal energy storage in building *** coal (SC) after vanadium extraction treatment shows potential for secondary utilization in composite *** prepared SC-based composite PCMs with SC as a matrix,stearic acid (SA) as a PCM,and expanded graphite (EG) as an *** combined roasting and acid leaching treatment of raw SC was conducted to understand the effect of vanadium extraction on promoting loading *** showed that the combined treatment of roasting at 900℃ and leaching increased the SC loading of the composite by 6.2%by improving the specific surface *** loading capacity and thermal conductivity of the composite obviously increased by 127%and 48.19%,respectively,due to the contribution of 3wt% *** data were supported by the high load of 66.69%and thermal conductivity of 0.59 W·m^(-1)·K-1of the designed *** obtained composite exhibited a phase change temperature of 52.17℃,melting latent heat of 121.5 J·g^(-1),and good chemical *** SC-based composite has prospects in building applications exploiting the secondary utilization of minerals.

关键词： thermal energy storage phase change material stone coal vanadium extraction secondary utilization

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A Physical-Statistical Model for Rainstorm Inundation of Substation 1

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2nd International Conference on Internet of Things, Communication and Intelligent Technology, IoTCIT 2023

作者： Wang, Lei Feng, Tao Cai, Zelin Li, Li Xu, Xunjian State Key Laboratory of Disaster Prevention and Reduction for Power Grid Transmission and Distribution Equipment Changsha China

ISBN: (数字)9789819727575

ISBN: (纸本)9789819727568

disaster prediction can buy valuable time for power grid disaster prevention and reduction. In this study, we firstly propose a physical statistical method for substation inundation prediction, which can comprehensively consider geographic features, real-time water level height of substation, precipitation amount, substation water collection capacity and drainage capacity. Nine substations in Changsha City, Hunan Province, are then analyzed separately and inundation prediction models are established using the rainstorm and substation inundation process in May 2022. The accuracy of the models are finally verified by using the heavy rainfall process in July 2022. The results show that the model can reproduce the process of water level variation in the substation, with a height error of less than 5cm. Subsequently, those models can combine the refined precipitation prediction data to carry out real-time prediction of substation inundation risk and hopefully improve the substation rainstorm disaster resistance. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： disaster prevention

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Transmission Line Geological Hazard Detection Based on UAV LiDAR DEM and InSAR

Transmission Line Geological Hazard Detection Based on UAV L...

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2023 International Conference on Smart Electrical grid and Renewable Energy, SEGRE 2023

作者： Tang, Zhaohua Fang, Zhen Sun, Yicheng Ouyang, Yi Zhang, Huayu State Key Laboratory of Disaster Prevention and Reduction for Power Grid Changsha China

ISBN: (纸本)9798350323269

Geological hazards near transmission towers can easily lead to exposed and damaged tower foundations, and in severe cases, cause towers to tilt and collapse. In 2022, there will be 2,884 geological hazards in Hunan. The heavy rain in Hunan from July 6 to 9, 2019 caused landslides on 36 main network lines, and among them, landslides occurred near 4 towers of the ±500kV Jiangcheng line. Geological hazards have become one of the major hazards threat to the safe operation of the line. Effective detection can discover hidden dangers of geological hazards in advance, to reduce casualties and economic losses. This paper proposed a "satellite-air"geological hazard detection method, based on satellite Interferometric Synthetic Aperture Radar (InSAR) data and unmanned aerial vehicle (UAV) Light Detection and Ranging (LiDAR) data, the joint analysis of optical remote sensing images and multi-phase Digital Elevation Model (DEM) images, and obtains features such as DEM difference, slope, slope aspect and mountain shadows, combined with the occurrence conditions of various geological hazards, the transmission line geological hazards have been effectively monitored. The experimental results on the two phases of Loudi InSAR and LiDAR data showed that our proposed method can accurately detect landslides and other hidden dangers of geological hazards, and has achieved good final results. © 2023 IEEE.

关键词： Landslides

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An accurate fault location method for distribution network considering the cumulative deviation of wave speed 3

An accurate fault location method for distribution network c...

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3rd International Conference on Smart Energy and Electrical Engineering, SEEE 2024

作者： Liu, Beiyuan State Key Laboratory of Disaster Prevention & Reduction for Power Grid Changsha University of Science & Technology Changsha410114 China

In view of the low accuracy and poor stability of current distribution network traveling wave fault location methods due to wave speed errors, a new accurate distribution network fault location strategy and method is proposed, which especially considers traveling wave speed errors. Firstly, we quantitatively analyze the wave velocity error in fault calculation, and deeply discuss the causes and influencing factors of the wave velocity error in existing traveling wave location methods. Then, we study the catadioptric feature of fault waves in the feeder line, and based on this, we propose a traveling wave recognition technology based on projection intensity detection. On account of the catadioptric pattern of fault waves and the accumulation of wave velocity errors, an accurate fault location algorithm for the distribution system line is proposed. To verify the practicability of this positioning method in various fault scenarios, we built a distribution line topology model in a Matlab/Simulink environment and verified the positioning effect of this method in different fault locations and types through experiments. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Electric fault location

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