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CSEE Journal of power and Energy Systems 2022年第3期8卷 710-720页

作者： Lin Yu Huadong Sun Shiyun Xu Bing Zhao Jian Zhang state Key Laboratory of power grid Safety and Energy Conservation China Electric Power Research InstituteBeijing100192China

The power system is experiencing a higher penetration of renewable energy generations(REGs).The short circuit ratio(SCR)and the grid impedance ratio(GIR)are two indices to quantify the system strength of the power system with *** this paper,the critical short circuit ratio(CSCR)is defined as the corresponding SCR when the system voltage is in the critical stable *** static voltage stability analysis,the mathematical expression of the CSCR considering the impact of GIR is *** maximum value of CSCR is adopted as the critical value to distinguish the weak power *** on the static equivalent circuit analysis,it is proved that the CSCR is still effective to evaluate critical system strength considering the interactive impact among ***,we find that the GIR can be neglected and the SCR can be used individually to evaluate the system strength when SCR>2 or GIR>*** correctness and rationality of the CSCR and its critical value are validated on ADPSS.

关键词： Critical short circuit ratio critical value grid impedance ratio maximum power transfer theorem static equivalent circuit analysis

Low frequency oscillation characteristics of East China power grid after commissioning of Huai-Hu ultra-high voltage alternating current project

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Journal of Modern power Systems and Clean Energy 2015年第3期3卷 332-340页

作者： Chao WANG Yang LV Hongyang HUANG Jing ZHANG Jihong LI Yingyi LI Weizhen SUN Yong CHANG state grid Zhejiang electric power company Hangzhou 310007China state grid Jilin electric power company Changchun 130000China state grid Operation company Beijing 100052China

The low frequency oscillation characteristics of East China power grid after commissioning of the first ultra-high voltage alternating current(UHVAC)project-the Huai-Hu UHVAC project are *** low frequency oscillation cases occurred in East China power grid in the past few years are reviewed and *** on the analysis of the different typical operation modes,the main low frequency oscillation modes in East China power grid in the early stages of development of ultra-high voltage(UHV)are summarized,and the impacts of the significant power grid maintenance on low frequency oscillation characteristics are ***,the oscillation mode of UHV generators to East China power grid is researched,and the importance of the power system stabilizator(PSS)is ***,the comparative analysis between the time domain and the frequency domain is carried out,and the influences of the governing system on low frequency oscillation characteristics are ***,both the focus and the direction of low frequency oscillation research are presented.

关键词： Ultra-high voltage(UHV) Low frequency oscillation Forced oscillation power system stabilizator(PSS) Governing system

Three-phase fault direction identification method for outgoing transmission line of DFIG-based wind farms

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Journal of Modern power Systems and Clean Energy 2019年第5期7卷 1155-1164页

作者： Zhanfeng FAN Guobing SONG Xiaoning KANG Jisi TANG Xiaobo WANG Xi’an Jiaotong University Xi’anChina state grid beijing electric power company BeijingChina state grid Shanxi Maintenance company TaiyuanChina

Doubly-fed induction generator(DFIG)-based wind farm has the characteristic of transient fault with low voltage ride through(LVRT)capability.A new three-phase fault direction identification method for the outgoing transmission line of the wind farm is *** ability of the new directional relay to differentiate between a three-phase fault in one direction or the other is obtained by using the increment of phase angle difference between the memory voltage signal and the fault current signal within a certain time,and using the amplitude variation of the fault *** can be inferred that the fault current is supplied by the wind farm whether the phase angle differs or the current amplitude varies *** fault locations at the outgoing transmission line have been simulated by PSCAD/EMTDC to evaluate the reliability and sensitivity of the proposed *** show that the new directional relay is of faster response when a three-phase fault occurs at the outgoing transmission line of a DFIG-based wind farm.

关键词： Wind farm Doubly-fed induction generator(DFIG) Directional relay Outgoing transmission line

Operating system network security enhancement scheme based on trusted storage

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Intelligent and Converged Networks 2023年第2期4卷 127-141页

作者： Longyun Qi Xiaoliang Lv Lianwen Sun Tianle Yao Jianye Yu Lei Wang state grid electric power Research Institute Nanjing 210003China state grid beijing electric power company Beijing 100031China

Data storage security has become the core of many network security *** order to achieve trusted storage and trusted measurement of network community data,this paper proposes a secure storage model based on trust extension for existing trusted storage *** the process of document encryption,the key information is encrypted as well as decentralized stored by optimizing the ciphertext inverted index structure and update policy to ensure the security of index *** the process of user access control mechanism,SAML and XACML are used in combination with role-based access control in order to achieve flexible and efficient authorization and access *** the process of result query,ontology technology is introduced to better express the user’s query intention and improve the query accuracy.A large number of experiments demonstrate the effectiveness and feasibility of the scheme.

关键词： trusted storage trust extension trusted platform model(TPM) access control

Space Charge Transient Kinetic Characteristics in DC Air Corona Discharge at Atmospheric Pressure

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Plasma Science and Technology 2014年第8期16卷 749-757页

作者：刘兴华咸日常孙学峰王涛吕学宾陈素红杨帆 state grid Zibo power Supply company state grid Shandong electric power company state grid Shandong electric power Research Institute state Key Laboratory of power Transmission Equipment & System Security and New Technology Chongqing University

Investigating the corona mechanism plays a key role in enhancing the performance of electrical insulation systems. Numerical simulation offers a better understanding of the physical characteristics of air corona discharges. Using a two-dimensional axisymmetrical kinetics model, into which the photoionization effect is incorporated, the DC air corona discharge at atmosphere pressure is studied. The plasma model is based on a self-consistent, multi-component, and con- tinuum description of the air discharge, which is comprised of 12 species and 22 reactions. The discharge voltage-current characteristic predicted by the model is found to be in quite good agree- ment with experimental measurements. The behavior of the electronic avalanche progress is Mso described. 0＋ and N＋ are the dominant positive ions, and the values of 0- and 02 densities are much smaller than that of the electron. The electron and positive ion have a low-density thin layer near the anode, which is a result of the surface reaction and absorption effect of the electrode. As time progresses, the electric field increases and extends along the cathode surface, whereas the cathode fall shrinks after the corona discharge hits the cathode; thus, in the cathode sheath, the electron temperature increases and the position of its peak approaches to the cathode. The present computational model contributes to the understanding of this physical mechanism, and suggests ways to improve the electrical insulation system.

关键词： air corona discharge atmospheric pressure numerical simulation mechanism

Generation dispatch method based on maximum entropy principle for power systems with high penetration of wind power

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Journal of Modern power Systems and Clean Energy 2018年第6期6卷 1213-1222页

作者： Qiaoyan BIAN Yutao QIU Wenlian WU Huanhai XIN Xuhua FU Hangzhou power Supply company of state grid Zhejiang electric power company state grid Zhejiang electric power company College of electrical Engineering Zhejiang University Zhejiang power Economic Research Institute of state grid

This paper proposes a generation dispatch model based on the maximum entropy principle. The objective is to find an optimal generation dispatch strategy that minimizes the generation cost and satisfies the security constraints of power systems, while taking into account the uncertainty of wind power. Since in many situations, only partial information of the probabilistic variables can be obtained, the maximum entropy principle is introduced to find the most likely realized probability distributions of the power flow, thus providing an accurate probabilistic circumstance to solve the generation dispatch model. The proposed method is tested on the IEEE 39-bus system, and is compared with the methodologies based on Monte Carlo simulation and Gram-Charlier expansions.

关键词： Generation dispatch Strategy Maximum entropy Probability distribution Cumulant

Mathematical methods for main tenance and operation cost prediction based on transfer learning in state grid

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Applied Mathematics(A Journal of Chinese Universities) 2022年第4期37卷 598-614页

作者： GUO Yun-peng WANG Dong-fa ZHENG Ying DING Wei-bin state grid Zhejiang electric power company Jinhua power Supply company Jinhua 321000China state grid Zhejiang electric power company Hangzhou 310018China

The electric power enterprise is an important basic energy industry for national development,and it is also the first basic industry of the national *** the continuous expansion of state grid,the progressively complex operating conditions,and the increasing scope and frequency of data collection,how to make reasonable use of electrical big data,improve utilization,and provide a theoretical basis for the reliability of state grid operation,has become a new research hot *** electrical data has the characteristics of large volume,multiple types,low-value density,and fast processing speed,it is a challenge to mine and analyze it deeply,extract valuable information efficiently,and serve for the actual *** to the features of these data,this paper uses artificial intelligence methods such as time series and support vector regression to establish a data mining network model for standard cost prediction through transfer *** experimental results show that the model in this paper obtains better prediction results on a small sample data set,which verifies the feasibility of the deep transfer *** with activity-based costing and the traditional prediction method,the average absolute error of the proposed method is reduced by 10%,which is effective and superior.

关键词： transfer learning LSTM support vector regression activity based costing state grid

Model predictive control and improved low-pass filtering strategies based on wind power fluctuation mitigation

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Journal of Modern power Systems and Clean Energy 2019年第3期7卷 512-524页

作者： Yushu SUN Xisheng TANG Xiaozhe SUN Dongqiang JIA Zhihuang CAO Jing PAN Bin XU Institute of electrical Engineering Chinese Academy of SciencesBeijing 100190China Sinopec Oilfield Service Shengli Corporation Tarim Branch company Korla 841000China state grid beijing electric power company electric power Research Institute Beijing 100075China state grid Anhui electric power company Hefei 230000China

The rapid development of renewable energy sources such as wind power has brought great challenges to the power grid. Wind power penetration can be improved by using hybrid energy storage(ES) to mitigate wind power fluctuation. We studied the strategy of smoothing wind power fluctuation and the strategy of hybrid ES power distribution. Firstly, an effective control strategy can be extracted by comparing constant-time low-pass filtering(CLF), variable-time low-pass filtering(VLF), wavelet packet decomposition(WPD), empirical mode decomposition(EMD) and model predictive control algorithms with fluctuation rate constraints of the identical grid-connected wind power. Moreover, the mean frequency of ES as the cutoff frequency can be acquired by the Hilbert Huang transform(HHT), and the time constant of filtering algorithm can be obtained. Then, an improved low-pass filtering algorithm(ILFA) is proposed to achieve the power allocation between lithium battery(LB) and supercapacitor(SC), which can overcome the over-charge and over-discharge of ES in the traditional low-pass filtering algorithm(TLFA). In addition, the optimized LB and SC power are further obtained based on the SC priority control strategy combined with the fuzzy control(FC) method. Finally, simulation results show that wind power fluctuation can be effectively suppressed by LB and SC based on the proposed control strategies, which is beneficial to the development of wind and storage system.

关键词： Wind power fluctuation mitigation Control strategies Model predictive control algorithm Hybrid energy storage(ES) Improved low-pass filtering algorithm(ILFA) Fuzzy control(FC) Strategy

Subsynchronous resonance and its mitigation for power system with unified power flow controller

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Journal of Modern power Systems and Clean Energy 2018年第1期6卷 181-189页

作者： Xinyao ZHU Meng JIN Xiangping KONG Jingbo ZHAO Jiankun LIU Qian ZHOU state grid Jiangsu electric power Research Institute state grid Jiangsu electric power Maintenance Branch company

Control strategy of unified power flow controller(UPFC)utilizing dq decoupling control is deduced in this paper,which can closely follow the control orders of the active and reactive *** subsynchronous resonance(SSR)characteristics of a series compensated system equipped with UPFC are studied,and the results reveal that SSR characteristics of the system may vary significantly with UPFC in service or ***,supplementary subsynchronous damping controller(SSDC)for UPFC is proposed and investigated,and the effectiveness of the proposed SSDC is verified by damping torque analysis and time domain simulations.

关键词： Unified power flow controller(UPFC) Series capacitor compensation Subsynchronous resonance(SSR) Supplementary subsynchronous damping controller(SSDC) Damping torque analysis

Infuences of Different Admixtures on the Drying Shrinkage Characteristics of Metakaolin-based Geopolymer Mortar

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Journal of Wuhan University of Technology(Materials Science) 2024年第6期39卷 1425-1433页

作者： ZHI Jing ZHANG Chengyang WANG Yunwen WEI Libao ZHANG Pan state grid Gansu electric power company Wuwei power Supply company Wuwei 733000China state grid Gansu electric power company Baiyin power Supply company Baiyin 730900China

To investigate the influences of different admixtures on the drying shrinkage of polymer mortar in a metakaolin base,the experiments of VAE(vinyl acetate ethylene copolymer),APAM(anionic polyacrylamide)and CPAM(cationic polyacrylamide)on the drying shrinkage properties of geopolymer mortar were designed under normal temperature curing *** SP-175 mortar shrinkage dilatometer was introduced to measure the dry shrinkage of geopolymer ***,the drying shrinkage properties of geopolymer mortar are exhibited by the parameters of water loss rate,drying shrinkage rate,drying shrinkage strain and drying shrinkage *** experimental data are further fitted to obtain the prediction model of dry shrinkage of geopolymer mortar,which can better reflect the relationship between dry shrinkage rate and ***,the experimental results demonstrate that the dry shrinkage of geopolymer mortar can be significantly increased by adding 4%VAE admixture,meanwhile under the condition that the polymer film formed by VAE reaction can strengthen and toughen the mortar.2.5%APAM admixture and 1.5%CPAM admixture can enhance the dry shrinkage performance of geopolymer mortar in a certain range.

关键词： metakaolin base polymer mortar dry shrinkage property admixture dry shrinkage prediction model