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High Voltage 2023年第5期8卷 967-976页

作者： Yanpeng Hao Peng Zhao Baojun Hui Yanting Cheng Wenbo Zhu Mingli Fu Xiaodong Li School of electric power Engineering South China University of TechnologyGuangzhouChina china Southern power Grid electric power research institute Co.Ltd GuangzhouChina

The buffer layer defects of high‐voltage crosslinked polyethylene(XLPE)cable occur frequently,which makes the detection method become the focus to be ***,the broadband impedance detection technology for the buffer layer defects of high‐voltage XLPE cables with corrugated aluminium sheath is *** are nine cable samples,including new and defective *** of the defective cables are artificial,and the other is retired *** influence of wiring mode,the circumferential relative position of electrodes,cable length,artificial white powder,artificial damp,and retired defective cables on the impedance spectrum is *** is found that the wiring mode of the insulation shield/aluminium sheath at the end of the cable can effectively detect the buffer layer *** the broadband impedance amplitude spectrum of the buffer layer in defective cable,measuring at various circumferential relative positions,is obviously *** there are white powders,air gaps,or ablation in the buffer layer,the broadband impedance spectrum(BIS)will increase by several *** the buffer layer is damped,the BIS will *** research here provides theoretical support and technical methods for the buffer layer defects of XLPE cable with corrugated aluminium sheath.

关键词： impedance spectrum layer

Sequential auto-reclosing strategy for hybrid HVDC breakers in VSC-based DC grids

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Journal of Modern power Systems and Clean Energy 2019年第3期7卷 633-643页

作者： Xiangyu PEI Guangfu TANG Shengmei ZHANG china electric power research institute Beijing100192China Global Energy Interconnection research institute Co.Ltd. Beijing102209China north china electric power university Beijing102206China

The use of overhead lines for power transmission in the future high-voltage and large-capacity voltagesource converter(VSC)-based direct current(DC) grid will significantly increase the probability of temporary *** eliminate potential adverse impacts such as erroneous protection, line-insulation failure, and even damage to power electronic devices resulting from a DC breaker reclosing operation with the traditional sequential autoreclosing strategy, a new sequential auto-reclosing strat-egy for hybrid HVDC breakers(HHBs) in VSC-based DC grids is proposed. This strategy is based on the step-by-step operation of the transfer branch in the HHB. As a result,du/dt resulting from the HHB reclosing operation is greatly reduced, and therefore those potential negative impacts can be eliminated. Several other advantages are also *** feasibility and validity of the proposed strategy are verified in a four-terminal annular VSC-based DC grid electromagnetic transient model.

关键词： Overhead line Voltage-sourced converter(VSC)-based direct current grid Temporary fault Hybrid HVDC breaker(HHB) Auto-reclosing strategy

Adsorption of boron and its relationship with morphologies of TiC

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Rare Metals 2016年第9期35卷 705-710页

作者： Hai-Min Ding Xiao-Liang Fan Xin-Chun Zhang Ze-You Zheng School of Energy power and Mechanical Engineering North China Electric Power University

First-principle calculations were performed to study the adsorption of boron and its relationship with the morphologies of Ti *** is found that although the adsorption of boron on all the low-index Ti C crystal planes is thermally favorable,it will be adsorbed more easily by C-terminated {111} and {011} planes,while less possible to be adsorbed by {001}.The study of the formation of B–B clusters indicates that the distribution of boron adatoms on C-terminated（111） and {011} planes will be more uniform,and the diffusion of the adatom further confirms the above *** to the geometry relationship and growth rate of different crystal planes,it is deduced that the adsorption of boron on Ti C will seriously impede the growth of {111} and {011} planes,which can make Ti C grow into hexagonal platelets.

关键词： Ti C Adsorption Surfaces and interfaces First-principle calculations

A Passive Anti-icing Strategy Based on a Superhydrophobic Mesh with Extremely Low Ice Adhesion Strength

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Journal of Bionic Engineering 2021年第1期18卷 55-64页

作者： Peng Wang Ziqiang Li Qing Xie wei Duan Xinchun Zhang Huilong Han School of Energy Power and Mechanical EngineeringNorth China Electric Power UniversityBaoding 071000China Hebei Key Laboratory of electric Machinery Health Maintenance&Failure Prevention North China Electric Power UniversityBaoding 071003China School of electrical and Electronic Engineering North China Electric Power UniversityBaoding 071003China

Although superhydrophobic materials have attracted much research interest in anti-icing,some controversy still *** this research,we report a cost-effective method used to verify the contribution of area fraction to ice adhesion *** tried to partially-embed siliea nanopnarticles into microscale fabrics of a commercial polyamide ***,the area fraction could be determined by altering the mesh ***,the ice adhesion strength decreases as the area fraction *** ice adhesion strength of~1.9 kPa and a delayed freezing time of~1048 s can be *** attribute the low ice adhesion strength to the combination of superhydro-phobicity and stress *** superhydrophobicity prohibits the water from penetrating into the voids of the meshes,and the small actual contact area leads to stress concentration which promotes interfacial crack ***,our superhydrophobic mesh simultaneously exhibis a micro-nano hierarchical structure and a partally-cmbedded ***,the as-prepared superhydrophobic mesh retained the ieephobicity after 20 icingldeicing cycles,and maintained its superhydrophobicity even afier 60 sandpaper-abrasion cycles and a 220"C thermal treatment.

关键词： bionic superhydrophobic anti-icing mechanical robustness hierarchical structure partially-embedded structure

Correlation between electronic structure and energy band in Eu-doped CuInTe_2 semiconductor compound with chalcopyrite structure

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Chinese Physics B 2017年第10期26卷 157-164页

作者：王泰郭永权李帅 School of Energy power and Mechanical Engineering North China Electric Power University

The Eu-doped Cu（In, Eu）Te2 semiconductors with chalcopyrite structures are promising materials for their applications in the absorption layer for thin-film solar cells due to their wider band-gaps and better optical properties than those of CuInTe2. In this paper, the Eu-doped CuInTe2 （CuIn1-xEuxTe2, x = 0, 0.1, 0.2, 0.3） are studied systemically based on the empirical electron theory （EET）. The studies cover crystal structures, bonding regularities, cohesive energies, energy levels, and valence electron structures. The theoretical values fit the experimental results very well. The physical mechanism of a broadened band-gap induced by Eu doping into CuInTe2 is the transitions between different hybridization energy levels induced by electron hopping between s and d orbitals and the transformations from the lattice electrons to valence electrons for Cu and In ions. The research results reveal that the photovoltaic effect induces the increase of lattice electrons of In and causes the electric resistivity to decrease. The Eu doping into CuInTe2 mainly influences the transition between different hybridization energy levels for Cu atoms, which shows that the 3d electron numbers of Cu atoms change before and after Eu doping. In single phase CuIn1-xEuxTe2, the number of valence electrons changes regularly with increasing Eu content, and the calculated band gap Eg also increases, which implies that the optical properties of Eu-doped CuIn1-xEuxTe2 are improved.

关键词： CuIn1-xEuxYe2 EET solar cells valence electronic structures band gap

Experimental Study on the Condensation of a Thermosyphon by electrical Capacitance Tomography

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Journal of Thermal Science 2016年第2期25卷 171-177页

作者： HAN Zhenxing MU Huaiping LEI Jing ZHANG Jingyin LI Zhihong LIU Shi School of Energy Power and Mechanical Engineering North China Electric Power University

The study on the condensation and the two-phase flow pattern in the condensation section is important to understand the operating mechanisms in a thermosyphon. In this paper, a new electric capacitance tomography(ECT) sensor was designed for the visualization measurement in a liquid by removing the shielding case and sealing with insulating hydrophobic material. It was successfully used to measure the condensation process in a thermosyphon under different operating temperatures. The thermosyphon was made of silica glass, and alcohol was used as a working fluid. The alcohol vapor was cooled to condense through the heat convection with the cooling water. The operating temperature was controlled by a heater with different power outputs. The experimental results show that the alcohol vapor condensed in stripes and unevenly on the wall surface at a low operating temperature. The liquid bridge will be formed periodically at the operating temperature of 90?C, and the time interval between two liquid bridges will be shorter with the increase of the operating temperature. At 117?C or even higher operating temperatures, the complete liquid bridge cannot be formed sometimes due to the difference of the growth rate of the surface wave around the circumference.

关键词： Thermosyphon Condensation ECT Visualization

research on Two-stage Voltage and Reactive power Optimization Coordinated Control Method Considering Flexible On-load Tap Changer

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Dianwang Jishu/power System Technology 2025年第1期49卷 272-283页

作者： Li, Jiaming Huo, Qunhai Yin, Jingyuan Lu, Hao Zhou, Jing Zhu, Meisheng He, Wei Dong, Hongwei institute of electrical Engineering Chinese Academy of Sciences Haidian District Beijing 100192 China School of Electronic Electrical and Communication Engineering University of Chinese Academy of Sciences Shijingshan District Beijing 100049 China Shanghai Jiguang Polytechnic College Baoshan District Shanghai 201901 China Three Gorges electric power Co. Ltd. Hubei Province Wuhan 430000 China

With the large-scale integration of distributed photovoltaic (DPV) in the distribution network, voltage exceeding limits and fluctuations are becoming increasingly severe. The voltage and reactive power optimization and coordination control method considering new power quality management devices needs to be further improved to adapt to the new changes in the power grid. This article considers the power quality regulation effect of the new flexible on-load tap changer (OLTC) and proposes a two-stage voltage and reactive power optimization coordinated control method. The first stage is the day before hour level scheduling stage. Based on distributed photovoltaic and load prediction data, the active output results of DPV and the switching results of flexible OLTC taps and capacitor banks are obtained through power flow calculation and iterative optimization. The second stage is the minute-level reactive power optimization stage. Based on the first stage, considering the reactive power output characteristics of flexible OLTC and DPV, adjusting the reactive power output of the equipment while correcting the capacitor bank switching combination in the first stage, further reducing the maximum voltage deviation of each node and making the distribution network voltage distribution more reasonable. An IEEE33 node distribution system simulation model is built in the paper. The proposed two-stage voltage and reactive power optimization coordination control method considering flexible OLTC can improve the DPV absorption level by 9.29% based on the conventional economic optimal goal of 88.07%, while meeting the requirement that the voltage deviation of the entire node is less than 0.1pu During the entire period, the overall economic efficiency improved by 7.8%. The results demonstrate the rationality and effectiveness of the proposed method. © 2025 power System Technology Press. All rights reserved.

关键词： Quality management

Performance Assessment of Air-Cooled Steam Condenser with Guide Vane Cascade

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Journal of Thermal Science 2019年第5期28卷 993-1003页

作者： ZHANG Xuelei LI Yunpeng CHEN Haiping School of Energy Power and Mechanical Engineering North China Electric Power University

Ambient wind has an unfavourable impact on air-cooled steam condenser(ACSC) performance. A new measure to improve ACSC performance is proposed by setting a diffusion type guide vane cascade beneath the ACSC platform. The numerical models are developed to illustrate the effects of diffusion type guide vane cascade on ACSC performance. The simulation results show that this vane cascade can cause the increases in coolant flows across almost all fans due to its diffusion function and lower flow resistance. Meanwhile, the guide vane cascade also decreases the fan inlet temperatures because of the uniform flow field around the condenser cells. Comparing with the case without guide device, the overall heat transfer efficiency is increased by 11.2% for guide vane cascade case under the condition of 9 m/s. The heat transfer efficiency firstly enhances and then decreases with decreasing stagger angle of guide vane under a certain wind speed. The optimum stagger angle corresponding to the maximum heat transfer efficiency is about 65.5°. The heat transfer efficiency always enhances as increasing vane cascade height, and a vane cascade with 20 m to 30 m height may be suitable to the ACSC as considering the cost.

关键词： air-cooled steam condenser ambient wind guide vane cascade heat transfer

Dynamic Capture Method for Out-of-step Center of power Grid Based on Measurement Information

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CSEE Journal of power and Energy Systems 2021年第6期7卷 1256-1266页

作者： Zonghan Li Dongxia Zhang Daowei Liu Shaobo Yang Gaoshang Zhao china electric power research institute Beijing 100192China the School of electrical Engineering Northeast Electric Power UniversityJilin Province 132012China

This paper dynamically captures the out-of-step center for a bulk power system based on measurement ***,the position characteristics of the out-of-step center are discussed from the perspective of triangular geometry under different potential and uniform impedance distributions based on a two-machine *** correlation between the out-of-step center and the oscillation center is ***,combined with analytical geometry,it is inferred that the distribution characteristics of the out-of-step center voltage vector ends are a circle or a straight line,and the position of the out-of-step center corresponds to the intersection between the voltage drop of the line and the distribution characteristics;then,the accurate location of the out-of-step center and the determination of the appearance moment is ***,a dynamic equivalence method for a power grid is proposed based on the electrical parameters of the transmission line,and an alternative iterative correction of equivalent parameters is carried out by trajectory sensitivity,which provides a new way for capturing the out-ofstep center dynamically in a multimachine *** proposed method is validated using a three-machine system,the IEEE-39 system and the northwest china power Grid,and shows potential for online applications.

关键词： Dynamic equivalence geometric characteristics accurate location out-of-step center

Wind power forecasting error-based dispatch method for wind farm cluster

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Journal of Modern power Systems and Clean Energy 2013年第1期1卷 65-72页

作者： Ning CHEN Qi WANG Liangzhong YAO Lingzhi ZHU Yi TANG Fubao WU Mei CHEN Ningbo WANG china electric power research institute Nanjing 210003China Southeast university Nanjing 210096China china electric power research institute Beijing 100192China Gansu electric power Company Lanzhou 730050China

With the technical development of wind power forecasting,making wind power generation schedule in power systems become an inevitable *** paper proposes a new dispatch method for wind farm(WF)cluster by considering wind power forecasting errors.A probability distribution model of wind power forecasting errors and a mathematic expectation of the power shortage caused by forecasting errors are ***,the total mathematic expectation of power shortage from all WFs is *** study with respect to power dispatch in a WF cluster is conducted using forecasting and actual wind power data within 30 days from sites located at Gansu *** with the variable proportion method,the power shortage of the WF cluster caused by wind power forecasting errors is *** with the increment of wind power integrated into power systems,the method positively influences future wind power operation.

关键词： Wind power Dispatch Forecasting error Probabilistic distribution