检索结果-内蒙古大学图书馆

Photodetector array for measuring the spatial-temporal distribution characteristics of electric field in oil-pressboard insulation based on the Kerr electro-optic effect

引用

High Voltage 2025年第1期10卷 95-105页

作者： Chunjia Gao Bo Qi Chengrong Li Yukung Zheng State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

Accurate measurement and effective analysis of the space electric field and charge characteristics within the oil-pressboard insulation structure of converter transformer are essential for achieving precise insulation structure ***,most electric field measurement methods relying on the Kerr electro-optical effect are limited to single-point *** the complexity of converter transformer insulation struc-tures,including their large scale and the use of various materials,existing technologies and findings struggle to provide comprehensive electric field observations within the oil-pressboard *** leveraging the Kerr electro-optic effect,a high-precision 32-unit photodetector array has been developed to achieve regional measurements of spatial-temporal electric field in oil-pressboard *** array boasts a measure-ment spatial resolution of 1.4 mm^(2)and a sensitivity of 0.15 kV/mm,ensuring mea-surement accuracy exceeding 96.50%.Through practical measurements of the spatial electric field distribution within the oil-pressboard insulation under direct current voltage,the non-uniform distribution of the electric field is effectively captured in ***,the maximum deviation in field strength at different positions within the transformer oil can reach 18.5%.Moreover,as the applied voltage increases,the un-evenness coefficient of the field strength gradually rises,peaking at 1.19,which signifies a progressive expansion in the area affected by electric field *** conducting tests to assess the dispersion of volume resistivity in samples from various positions within large sheets of pressboard,the variation in volume resistivity of materials is posited as one of the contributing factors to the non-uniform distribution of electric field within the *** detailed accomplishments aim to provide essential technical and theoretical support for optimising insulation structure design of converter transformers.

关键词： insulation distribution field

来源：评论

学校读者我要写书评

暂无评论

Parallel multi-rate simulation scheme for modular multilevel converter-based high-voltage direct current with accurate simulation of high-frequency characteristics and field programmable gate array-based implementation

引用

High Voltage 2025年第1期10卷 17-31页

作者： Chongru Liu Yanqi Hou Haoyun Dong Yipeng Lv Xinyan Wang Chenbo Su State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

The real-time simulation of the modular multilevel converter-based high-voltage direct current(MMC-HVDC)transmission system has become a popular research ***,in order to meet the real-time performance,the real-time simulation tech-nology will cause additional simulation errors for MMC-HVDC,especially on its fre-quency ***,a parallel multi-rate simulation scheme for MMC-HVDC is developed in this work to ensure accurate simulation of high-frequency ***,a non-error method based on converter transformer decoupling is proposed to decouple the converter and alternating current system;direct current transmission line decoupling and arm decoupling methods are used to achieve decoupling among and within converters.A multi-rate data synchronous mechanism is established by considering the differences among high-frequency characteristics caused by delayed data ***,the computing architectures of the primary system solver and modular multilevel converter controller are designed based on a field programmable gate array(FPGA).The real-time simulation platform for a four-terminal true bipolar MMC-HVDC is constructed based on the FPGA ***,the factors in multi-rate simulation affecting the simulation accuracy of high-frequency characteristics are *** simulator is shown to be accurate in steady and dynamic *** authors also verify its applicability for further research on high-frequency resonance based on control experiments.

关键词： interaction characteristics scheme

来源：评论

学校读者我要写书评

暂无评论

Unifying Fixed Time and Prescribed Time Control for Strict-Feedback Nonlinear systems

引用

IEEE/CAA Journal of Automatica Sinica 2025年第2期12卷 347-355页

作者： Xiang Chen Yujuan Wang Yongduan Song the State Key Laboratory of Power Transmission Equipment & System Security and New Technology and School of Automation Chongqing University IEEE

This paper investigates the prescribed-time tracking control problem for a class of multi-input multi-output(MIMO)nonlinear strict-feedback systems subject to non-vanishing uncertainties. The inherent unmatched and non-vanishing uncertainties make the prescribed-time control problem become much more nontrivial. The solution to address the challenges mentioned above involves incorporating a prescribed-time filter, as opposed to a finite-time filter, and formulating a prescribed-time Lyapunov stability lemma(Lemma 5). The prescribed-time Lyapunov stability lemma is based on time axis shifting time-varying yet bounded gain, which establishes a novel link between the fixed-time and prescribed-time control method. This allows the restriction condition that the time-varying gain function must satisfy as imposed in most exist prescribed-time control works to be removed. Under the proposed control method, the desire trajectory is ensured to closely track the output of the system in prescribed time. The effectiveness of the theoretical results are verified through numerical simulation.

关键词： Prescribed-time control prescribed-time filter robust control state feedback strict-feedback systems

来源：评论

学校读者我要写书评

暂无评论

Modified Dynamic Model and Small-signal Stability Analysis for LCC- HVDC systems

引用

CSEE Journal of power and Energy systems 2025年第2期11卷 750-759页

作者： Chunyi Guo Jiaqing Zhang Shuo Yang Huan Li Chuang Fu State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Electric Power Research Institute China Southern Power Grid State Key Laboratory of HVDCGuangzhouChina

Inaccuracy of modeling for line commutated converter based high voltage direct current (LCC-HVDC) systems will degrade the reliability of small-signal stability analysis results. Taking a practical project as the study system, this paper establishes a modified dynamic model by modifying the current switching function, firing angle calculation and DC voltage calculation. Then, the accuracy of the modified model is verified by a detailed electromagnetic transient (EMT) simulation. Finally, with the modified dynamic model, the impact of the control parameters and AC system strength on the small-signal stability of the overall system is investigated by adopting the eigen-analysis. The results clearly demonstrate that the modified model shows higher accuracy than the original model.

关键词： LCC-HVDC modified dynamic model practical project small-signal analysis

来源：评论

学校读者我要写书评

暂无评论

Cooperative Control of FFM-CSC Using Positive and Negative Trigger Angle for Offshore Wind power Transmission

引用

IEEE Transactions on power Delivery 2025年第3期40卷 1574-1586页

作者： Feng, Dingteng Xiong, Xiaoling Yao, Chenhao Zhou, Zihan Zhao, Chengyong State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources Beijing102206 China

The current source converter (CSC) is a competitive solution for offshore wind grid integration. The fundamental frequency modulation-based current source converter (FFM-CSC) effectively solves the shortcomings of pulse width modulation CSC (PWM-CSC), in which DC voltage ripple is drastic and electrical stresses are high. The independent control of offshore AC voltage and frequency requires two degrees of control freedom for the converter. Nevertheless, this is not possible for the FFM-CSC since it has single control degree of freedom. To solve this problem, a positive and negative trigger angle cooperative control method is developed for CSC-HVDC connected offshore wind farms. The positive and negative trigger angles of the high and low valves are adopted to stabilize the offshore AC grid and achieve independent control of voltage amplitude and frequency. Next, by exploring the monotonicity of the offshore voltage amplitude and frequency, the laws affecting the control objectives were analyzed. Then, the AC fault characteristics are analyzed, whilst the ride-through methods are investigated accordingly. Finally, experimental prototypes and simulation models are built to confirm the designed control strategy and fault ride-through mechanism. © 1986-2012 IEEE.

关键词： Voltage control Wind power generation Wind farms Reactive power Valves power system stability Filters Rectifiers Frequency modulation Frequency control

来源：评论

学校读者我要写书评

暂无评论

Model and Data Hybrid Driven Approach for Quantifying the Meteorology-Dependent Demand Flexibility of Building Thermal Loads

引用

CSEE Journal of power and Energy systems 2025年第1期11卷 394-405页

作者： Bo Hu Xin Cheng Changzheng Shao Tao Niu Chunyan Li Yue Sun Wei Huang Kaigui Xie State Key Laboratory of Power Transmission Equipment and System Security Chongqing UniversityChongqing400030China

Recently, the heat and electricity integrated energy system (HE-IES) has become a hot topic in both industry and academia. In the HE- IES, the potential flexibility of the buildings' thermal loads can be exploited to relax the heat power balance constraints and consequently allow a more flexible operation of the combined heat and power units. In this paper, model-driven and data-driven techniques are combined to quantify the demand flexibility of the buildings' thermal loads in a non-instructive way. First, the explicit analytical equivalent thermal parameter (ETP) model of the aggregated buildings is developed. The heat transfer coefficient (k) and thermal inertia coefficient (C) of the ETP model are designated to measure the potential demand flexibility. Second, the Particle Swarm Optimization optimized Radial Basis Function neural network (PSO-RBF) is used to identify the relationship between the values of k and C and the meteorological factors. To obtain the training data, an innovative two-stage regression method based on the adaptive temporal resolution is proposed to extract k and C values from the historical thermal load data. Finally, a flexible thermal load model is built based on the predictions of the meteorological factors, which can be conveniently incorporated into the online dispatch of the HE-IES. A comprehensive simulation environment is designed to verify the accuracy and availability of the proposed technique.

关键词： Flexibility of buildings'thermal loads heat and electricity integrated energy system meteorological factors model and data hybrid driven

来源：评论

学校读者我要写书评

暂无评论

Effects of Corona Discharge from the Grounding Tip on Charge Evolution of Wall Bushing

引用

IEEE Transactions on power Delivery 2025年第3期40卷 1682-1693页

作者： Bai, Zheng Zhou, Yuanxiang Zhang, Yunxiao Huang, Xin Xie, Xiongjie Liu, Taiwei Tsinghua University State Key Laboratory of Power System Operation and Control Department of Electrical Engineering Beijing100084 China Electric Power Research Institute State Key Laboratory of Power Grid Environmental Protection Wuhan430204 China

Manufacturers consider that the grounding tip near the wall bushing flange is a potentially important factor in several sheath perforation accidents. Taking a ±100 kV true type SF6 gas-insulated bushing as a typical wall bushing, this paper tests the impact of the nearby grounding tip on the charge accumulation. Based on the experiment results, we propose the three-dimensional nonlinear conduction model to unravel the charge accumulation process and the three-dimensional corona ion migration model to clarify the corona process. It is concluded that the consumption of gas ions leads to the nonlinear charge relaxation process. When the corona of grounding tip incepts, numerous ions are generated, forming an "overcharge" phenomenon. The electric field at the insulator-sheds interface and the SF6-insulator interface increases compared to the normal condition, with non-uniform distribution along the circumferential direction. Material inhomogeneity amplifies electric field distortion and creates insulation weaknesses, making insulation aging more likely and potentially leading to a slowly developing electrical tree breakdown process. The length of the needle tip affects the duration of the corona effect;an excessively long needle tip can cause a sustained corona discharge. This research provides a foundation for bushing accidents analysis and operation reliability improvement. © 1986-2012 IEEE.

关键词： Bushings

来源：评论

学校读者我要写书评

暂无评论

Quantitative analysis on the separated double schottky barrier for ZnO-based ceramic nanowire

引用

Ceramics International 2025年第10期51卷 13537-13544页

作者： Yang, Xiao Zhang, Han Qi, Bo Yu, Zexuan Li, Chuanyang Hu, Jun He, Jinliang State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power University Beijing102206 China State Key Laboratory of Power Systems Department of Electrical Engineering Tsinghua University Beijing100084 China

ZnO based ceramic nanowires or whiskers have been reported to possess good nonlinear conducting property similar with ZnO ceramic varistor. The energy band structure and nonlinear conduction process of the ceramic nanowire are different from the traditional back-to-back double schottky barrier structure while a model description has been absent. This paper has taken ceramic nanowire based on ZnO coated with Bi, Co oxide as an instance and proposed a separated double schottky model to quantitatively characterizes the process of interface charges at the reverse and forward bias side which are separately modulated by the corresponding voltage bias and barrier height. Computation result based on the model agree well with the measured nonlinear conducting behavior of a single ZnO ceramic nanowire and its nonlinear mechanism has been analyzed. On this basis, quantitative correlation between the property of a single ZnO ceramic nanowire and the overall nonlinear conducting behavior of its composite has been established. © 2025

关键词： II-VI semiconductors

来源：评论

学校读者我要写书评

暂无评论

Robust Scheduling of Fast-charging EVs with Exogenous and Endogenous Uncertainties for Urban power Congestion Relief

引用

IEEE Transactions on Industry Applications 2025年第3期61卷 4530-4540页

作者： Wang, Zhe Hu, Huanyu Pan, Xi'an Zhang, Zhi Huang, Liyan Yan, Tingyu North China Electric Power University Department of State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources Beijing102206 China

As fast-charging electric vehicles (FCEVs) become one of the primary modes of urban transportation, the randomness and uncertainty of users' charging behaviors pose significant congestion risks to the grid's scheduling. In this paper, the urban power system guides FCEVs to orderly charge through appropriate pricing strategies. To do this, a novel demand response (DR) model is established to simulate the spatial flexibility of FCEVs under different charging prices. In order to realistically reflect the power deviations when FCEVs participate in DR, a hybrid exogenous and endogenous uncertainty set is proposed to capture the effects of environmental and user psychological factors. Furthermore, a two-stage robust model is developed to relieve congestion. Specifically, a bi-level model is employed to optimize locational marginal electricity prices, aiming to achieve collaboration between transmission and distribution networks in the first stage. The two-stage robust model is then transformed into a tractable form and solved using the modified parametric column-and-constraint generation (CCG) algorithm proposed in this paper. Numerical simulations verify the proposed model and algorithm's effectiveness and practicability using both modified IEEE standard test cases and real-world cases from Puyang's urban power system in China. © 1972-2012 IEEE.

关键词： power distribution networks

来源：评论

学校读者我要写书评

暂无评论

Introducing deep trap states for high dielectric strength of aramid-based composite films

引用

High Voltage 2025年第1期10卷 197-207页

作者： Wenqi Zhang Qibin Wang Guangyi Shen Sidi Fan Xiaozhou Fan Rui Yang Yunpeng Liu Xiang Yu Fangcheng Lv School of Electrical and Electronic Engineering North China Electric Power UniversityBeijingChina Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina

Aramid nanofiber(ANF)-based composites have drawn tremendous interest in high-voltage electrical systems due to their superior insulation strength,thermal stability,and mechanical ***,the filler agglomeration and interface compatibility have retarded further improvement of the dielectric ***,the nano-titanium dioxide(TiO_(2))particles treated by aminopropyl triethoxysilane(APTES)serve as the inorganic fillers,which are doped in the ANF to prepare the composite nano-paper via the blade coating *** electrostatic interaction between the ANF and fillers highly promotes their uniform *** to the pure ANF paper,the composite paper has a denser structure with reduced pores and defects,which significantly improves its dielectric performance with inhibited partial discharge *** a filler loading of 3 wt%(mass fraction),the breakdown strength is increased by 70.5%to a maximum value of 358.1 kV/mm,while the bulk conductivity is minimised to 5.2×10^(-17)S/m,representing an 88.1%*** analysing the energy band structure of each component,energy barriers at the interface for electrons(1.48 eV)and holes(0.40 eV)are *** values indicate deepened trap energy levels,which greatly strengthen the carrier trapping effect for improved dielectric performance.

关键词： composite dielectric strength

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：