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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2023年第4期24卷 350-365页

作者： Mingchun LIN Guanqi WANG Jian ZHOU Wei ZHOU Ni AN Gang MA State Key Laboratory of Water Resources and Hydropower engineering Science Wuhan UniversityWuhan 430072China Institute of Water engineering Sciences Wuhan UniversityWuhan 430072China Power China Chengdu Engineering Co. Ltd.Chengdu 610072China power china Kunming engineering co. Ltd.Kunming 650051China

Granular geomaterials under different loading co.ditions manifest various behaviors,such as hysteresis.Understanding their hysteretic behavior and deformation characteristics is the basis for establishing a co.stitutive relation with excellent performance in deformation prediction.The deformation characteristics of crushable particle materials are analyzed through a series of cyclic loading tests co.ducted by numerical simulation.The hysteretic behavior is investigated from a particle scale.The increase in particles with co.tacts less than two may be responsible for the residual strain,and the particle breakage further promotes particle rearrangement and volume co.traction.Both the accumulation of plastic strain and the resilient modulus are found to be related to co.fining pressures,stress levels,cyclic loading amplitudes,and the number of cycles.The plastic strain accumulation can be written as a function of the number of cycles and an evolution function of resilient modulus is proposed.

关键词： Granular material Discrete element method(DEM) Plastic deformation Cyclic loading Hysteretic behavior

A Fast Approach for Predicting Aerodynamic Noise Sources of High-Speed Train Running in Tunnel

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co.puter Modeling in engineering & Sciences 2022年第3期130卷 1371-1386页

作者： Deng Qin Tian Li Honglin Wang Jizhong Yang Yao Jiang Jiye Zhang Haiquan Bi State Key Laboratory of Traction power Southwest Jiaotong UniversityChengdu610031China School of Mechanical engineering Southwest Jiaotong UniversityChengdu610031China china Railway Eryuan engineering Group co. Ltd.Chengdu610031China

The aerodynamic noise of high-speed trains passing through a tunnel has gradually beco.e an important issue.Numerical approaches for predicting the aerodynamic noise sources of high-speed trains running in tunnels are the key to alleviating aerodynamic noise issues.In this paper,two typical numerical methods are used to calculate the aerodynamic noise of high-speed trains.These are the static method co.bined with non-reflective boundary co.ditions and the dynamic mesh method co.bined with adaptive mesh.The fluctuating pressure,flow field and aerodynamic noise source are numerically simulated using the abovemethods.The results showthat the fluctuating pressure,flow field structure and noise source characteristics obtained using different methods,are basically co.sistent.co.pared to the dynamic mesh method,the pressure,vortex size and noise source radiation intensity,obtained by the static method,are larger.The differences are in the tail car and its wake.The two calculation methods show that the spectral characteristics of the surface noise source are co.sistent.The maximum difference in the sound pressure level is 1.9 dBA.The static method is more efficient and more suitable for engineering applications.

关键词： High-speed train tunnel numerical calculation method aerodynamic noise source flow field

Parameters Identification for Extended Debye Model of XLPE Cables Based on Sparsity-Promoting Dynamic Mode Deco.position Method

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Energy engineering 2023年第10期120卷 2433-2448页

作者： Weijun Wang Min Chen Hui Yin Yuan Li Guiyang power Supply Bureau Guizhou Power Grid Co.Ltd.Guiyang550004China co.lege of Electrical engineering Sichuan UniversityChengdu610065China

To identify the parameters of the extended Debye model of XLPE cables,and therefore evaluate the insulation performance of the samples,the sparsity-promoting dynamicmode deco.position(SPDMD)methodwas introduced,aswell the basics and processes of its applicationwere explained.The amplitude vector based on polarization current was first calculated.Based on the non-zero elements of the vector,the number of branches and parameters including the co.fficients and time co.stants of each branch of the extended Debye model were derived.Further research on parameter identification of XLPE cables at different aging stages based on the SPDMD method was carried out to verify the practicability of the method.co.pared with the traditional differential method,the simulation and experiment indicated that the SPDMD method can effectively avoid problems such as the relaxation peak being unobvious,and possessing more accuracy during the parameter identification.And due to the polarization current being less affected by the measurement noise than the depolarization current,the SPDMD identification results based on the polarization current spectral line proved to be better at reflecting the response characteristics of the dielectric.In addition,the time domain polarization current test results can be co.verted into the frequency domain,and then used to obtain the dielectric loss factor spectrum of the insulation.The integral of the dielectric loss factor on a frequency domain can effectively evaluate the insulation co.dition of the XLPE cable.

关键词： Cable insulation dielectric response sparsity-promoting dynamic mode deco.position parameter identification

Data-driven Inverter-based Volt/VAr co.trol for Partially Observable Distribution Networks

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CSEE Journal of power and Energy Systems 2023年第2期9卷 548-560页

作者： Tong Xu Wenchuan Wu Yiwen Hong Junjie Yu Fazhong Zhang Southwest Electric power Design Institute co. Ltd.of China Power Engineering Consulting GroupChengduSichuan 610021China Tsinghua University Beijing 100084China Department of Electrical engineering State Key Laboratory of Power SystemsTsinghua UniversityBeijing 100084China Guangdong power Grid Zhongshan power Supply Bureau Zhongshan 528400China

For active distribution networks(ADNs)integrated with massive inverter-based energy resources,it is impractical to maintain the accurate model and deploy measurements at all nodes due to the large-scale of ADNs.Thus,current models of ADNs usually involve significant errors or even unknown occurances.Moreover,ADNs are usually partially observable since only a few measurements are available at pilot nodes or nodes with significant users.To provide a practical Volt/Var co.trol(VVC)strategy for such networks,a data-driven VVC method is proposed in this paper.First,the system response policy,approximating the relationship between the co.trol variables and states of monitoring nodes,is estimated by a recursive regression closed-form solution.Then,based on real-time measurements and the newly updated system response policy,a VVC strategy with co.vergence guarantee is realized.Since the recursive regression solution is embedded in the co.trol stage,a data-driven closedloop VVC framework is established.The effectiveness of the proposed method is validated in an unbalanced distribution system co.sidering nonlinear loads,where not only the rapid and self-adaptive voltage regulation is realized,but also systemwide optimization is achieved.

关键词： Data-driven distribution networks partial observation Volt/VAr co.trol

深部岩体爆破爆炸地震波辐射模式与能量特性数值模拟研究

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Journal of Central South University 2022年第2期29卷 645-662页

作者：杨建华吴泽南孙文彬姚池王秋慧 School of Civil engineering and Architecture Nanchang UniversityNanchang 330031China power china Jiangxi Electric power engineering co. Ltd.Nanchang 330096China

对于深部岩体爆破,普遍认为地应力的存在将改变爆生裂纹的传播过程并最终影响岩体爆破开裂区的分布,但对于地应力作用下岩体爆破开裂区形态改变对爆炸地震波辐射模式的影响,目前还鲜有研究报道。本文采用SPH-FEM耦合数值模拟方法,研究... 详细信息

对于深部岩体爆破,普遍认为地应力的存在将改变爆生裂纹的传播过程并最终影响岩体爆破开裂区的分布,但对于地应力作用下岩体爆破开裂区形态改变对爆炸地震波辐射模式的影响,目前还鲜有研究报道。本文采用SPH-FEM耦合数值模拟方法,研究了地应力对岩体爆破开裂及爆炸地震波辐射模式和能量特性的影响。结果表明,在地应力作用下岩体爆破开裂区形态改变对爆炸地震波能量及组成成分具有显著的影响;随着地应力水平的提高,岩体爆破开裂区范围缩小,更多的爆炸能转化为地震波能量,地应力作用下爆破开裂区(即爆炸地震波产生区)范围缩小导致地震波的频率升高;在非静水地应力条件下,沿最小主应力方向传播的爆生裂纹更易受到地应力的抑制,因此沿该方向传播的地震波的能量密度更高;在非静水地应力条件下各向异性的岩体爆破开裂模式导致岩体应变能非对称地快速释放,从而在岩体中诱发剪切波。

关键词：爆破地应力地震波岩体开裂 SPH-FEM

Microanalysis of supersaturated gas release based on wall-attached bubbles

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Water Science and engineering 2021年第1期14卷 80-86页

作者： Lu Lin Ran Li Jing-jie Feng Ying-han Huang Xiao-dong Yong Yang-ming Ou You-quan Yuan State Key Laboratory of Hydraulics and Mountain River engineering Sichuan UniversityChengdu 610065China power china Zhongnan engineering co.poration Limited Changsha 410014China Sichuan Qingyuan engineering co.sulting co. Ltd.Chengdu 610072China co.lege of Architecture and Civil engineering Chengdu UniversityChengdu 610106China

Supersaturation of dissolved gases in natural water,due to spillage from high dams and other factors,may cause fish mortality.In previous experiments,the dissipation co.fficient has been used to denote the degassing process of total dissolved gas(TDG)saturation.These experiments mainly analyzed supersaturated TDG dissipation from a macrosco.ic view.To precisely clarify the mechanism of supersaturated TDG release,this study investigated bubble adsorption at a wall surface from a microsco.ic view.The experiment was co.ducted in a Plexiglas-wall co.tainer filled with supersaturated TDG water.A model that calculates the adsorption flux of supersaturated TDG by a solid wall,and helps describe co.struction for a co.tact angle at a three-phase intersection,was developed acco.ding to Young's equation.This model was used to investigate the formation process of bubbles adsorbed on a solid polymethyl methacrylate(PMMA)surface in supersaturated TDG water.The adsorption effect of a solid wall on TDG release was analyzed based on the experimental data.The modeling results were co.pared with observations under different wall area co.ditions,and it was found that TDG release tended to increase with wall area.This study helps improve our understanding of the mechanisms of supersaturated TDG release and provides an important theoretical method for accurate calculation of the release process.The adsorption flux model of the solid wall provides mitigation measures to co.bat the adverse effects of TDG supersaturation,which will be beneficial to the protection of aquatic organisms in hydropower-regulated rivers.

关键词： Supersaturation Total dissolved gas Wall-attached bubbles Release Calculation model

Stochastic Accelerated Alternating Direction Method of Multipliers for Hedging co.munication Noise in co.bined Heat and power Dispatch

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CSEE Journal of power and Energy Systems 2023年第2期9卷 696-706页

作者： Zhigang Li Xinyu Liang Fan Hu Wen Xiong Renbo Wu J.H.Zheng Q.H.Wu School of Electric power engineering South China University of TechnologyGuangzhou 510641China Guangzhou power Supply Bureau Guangdong Power Grid Co.LtdGuangzhouChina

co.bined heat and power dispatch(CHPD)opens a new window for increasing operational flexibility and reducing wind power curtailment.Electric power and district heating systems are independently co.trolled by different system operators;therefore,a decentralized solution paradigm is necessary for CHPD,in which only minor boundary information is required to be exchanged via a co.munication network.However,a nonideal co.munication environment with noise co.ld lead to divergence or inco.rect solutions of decentralized algorithms.To bridge this gap,this paper proposes a stochastic accelerated alternating direction method of multipliers(SA-ADMM)for hedging co.munication noise in CHPD.This algorithm provides a general framework to address more types of co.straint sets and separable objective functions than the existing stochastic ADMM.Different from the single noise sources co.sidered in the existing stochastic approximation methods,co.munication noise from multiple sources is addressed in both the local calculation and the variable update stages.Case studies of two test systems validate the effectiveness and robustness of the proposed SAADMM.

关键词： Alternating direction method of multipliers co.bined heat and power dispatch co.munication noise decentralized optimization

全尺寸交流500 kV输电杆塔复合横担的雷电闪络特性

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engineering 2023年第4期23卷 130-137,M0006页

作者：王乾梁曦东沈余峰刘书明左周高岩峰 State Lab of power System Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Shandong Electrical engineering and Equipment Group co. Ltd.Jinan 250024China North china Electric power Research Institute co. Ltd.Electric Power Research Institute of State Grid Jibei Electric Power Co.Ltd.Beijing 100045China

架空输电线路(OTL)一直以来都是电力传输的主要方式。随着输电电压和输电容量的迅速提高,输电杆塔的尺寸也随之增加,造成土地资源的大量占用。考虑到线路复合绝缘子的优异性能,复合横担有望成为这一问题的解决方案。在本文中,作者制备... 详细信息

架空输电线路(OTL)一直以来都是电力传输的主要方式。随着输电电压和输电容量的迅速提高,输电杆塔的尺寸也随之增加,造成土地资源的大量占用。考虑到线路复合绝缘子的优异性能,复合横担有望成为这一问题的解决方案。在本文中,作者制备了一个安装有复合横担的全尺寸交流(AC)500 kV输电杆塔,并施加了不同极性的雷电过电压。借助高速相机记录了流注-先导放电的过程,确认了闪络的主要路径。通过测量闪络电压并根据空气密度和湿度对结果进行修正,证实了放电的极性效应。继而,根据杆塔结构和闪络特性计算了杆塔的耐雷水平。基于全尺寸试验的结果与分析,确认了复合横担的可行性,并提出了结构优化方案。

关键词： co.posite cross arms Transmission tower Lightning flashover Streamer discharge Lightning withstand

NFHP-RN:AMethod of Few-Shot Network Attack Detection Based on the Network Flow Holographic Picture-ResNet

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co.puter Modeling in engineering & Sciences 2024年第7期140卷 929-955页

作者： Tao Yi Xingshu Chen Mingdong Yang Qindong Li Yi Zhu School of Cyber Science and engineering Sichuan UniversityChengdu610065China CyberScience Research Institute Sichuan UniversityChengdu610065China chengdu Fengwei Technology co. Ltd.Chengdu610041China

Due to the rapid evolution of Advanced Persistent Threats(APTs)attacks,the emergence of new and rare attack samples,and even those never seen before,make it challenging for traditional rule-based detection methods to extract universal rules for effective detection.With the progress in techniques such as transfer learning and meta-learning,few-shot network attack detection has progressed.However,challenges in few-shot network attack detection arise from the inability of time sequence flow features to adapt to the fixed length input requirement of deep learning,difficulties in capturing rich information from original flow in the case of insufficient samples,and the challenge of high-level abstract representation.To address these challenges,a few-shot network attack detection based on NFHP(Network Flow Holographic Picture)-RN(ResNet)is proposed.Specifically,leveraging inherent properties of images such as translation invariance,rotation invariance,scale invariance,and illumination invariance,network attack traffic features and co.textual relationships are intuitively represented in NFHP.In addition,an improved RN network model is employed for high-level abstract feature extraction,ensuring that the extracted high-level abstract features maintain the detailed characteristics of the original traffic behavior,regardless of changes in background traffic.Finally,a meta-learning model based on the self-attention mechanism is co.structed,achieving the detection of novel APT few-shot network attacks through the empirical generalization of high-level abstract feature representations of known-class network attack behaviors.Experimental results demonstrate that the proposed method can learn high-level abstract features of network attacks across different traffic detail granularities.co.paredwith state-of-the-artmethods,it achieves favorable accuracy,precision,recall,and F1 sco.es for the identification of unknown-class network attacks through cross-validation onmultiple datasets.

关键词： APT attacks spatial pyramid pooling NFHP(network flow holo-graphic picture) ResNet self-attention mechanism meta-learning

Aerodynamic Design of a Subsonic Evacuated Tube Train System

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Fluid Dynamics & Materials Processing 2020年第1期16卷 121-130页

作者： Tian Li Xiaohan Zhang Yao Jiang Weihua Zhang State Key Laboratory of Traction power Southwest Jiaotong UniversityChengdu610031China china Railway Eryuan engineering Group co. Ltd.Chengdu610031China

The so-called Evacuated Tube Train(ETT)is currently being proposed as a high-speed transportation system potentially co.petitive with airplane transportation.Aerodynamic resistance is one of the most crucial factors for the successful design of an ETT.In the present work,a three-dimensional co.cept ETT model has been elaborated.The aerodynamic characteristics of the subsonic ETT have been numerically simulated under different co.ditions.The train’s running speed varies from 600 km/h up to 1200 km/h,and the blockage ratio is in the range between 0.1 and 0.3.As the blocking ratio and running speed increase,the resistance of the head car increases greatly,while the resistance of the middle car changes slightly.The aerodynamic resistance of the tail car is affected by the shock wave emerging in the wake flow.Two different design criteria for the maximum allowed aerodynamic resistance are proposed for aerodynamic parameter matching.With an increase in the blockage ratio and running speed,the atmospheric pressure in the tube should be decreased to achieve a balance.

关键词： Evacuated tube train aerodynamic resistance blockage ratio shock wave