电阻分压的10KV电子式电压互感器分析

基于电阻分压器的电子式电压互感器的原理、结构和输出信号等与传统的电压互感器有很大不同,其性能主要受电阻特性和杂散电容的影响。本文从等效电路的角度分析了电阻特性和杂散电容对电子式电压互感器测量准确度的影响;利用Ansoft软件包建立分压器的有限元模型对杂散电容进行了计算分析,并根据杂散电容分布对屏蔽罩进行了设计。在理论分析基础上,研制了一台电阻分压式的10KV电子式电压互感器,并进行了准确度测试。     

电容分压型电子式电压互感器传感特性研究

建立集中和分布参数模型,分析了杂散电容对电容分压型电子式电压互感器的影响,并以10 kV CEVT的基本特性为参数建模,利用MATLAB和MULTISIM仿真比较不同参数和有杂散电容影响下的传感特性。实验表明,二次分压电阻的取值越小,其带宽越大、传变特性越好。通过合理选择R,可以较好地修正CEVT的暂态特性。此外,存有杂散电容会使得二次端输出电压减小。     

杂散电容对EVT传感性能影响研究

电子式电压互感器的精度会受杂散电容的影响。通过对10 k V电子式电压互感器建立数学模型,分析杂散电容对其传感特性的影响,在IEC60044-7标准下进行仿真研究。结果表明杂散电容对REVT的影响使得互感器的可信带宽为100 k Hz,传感器模型在100 k Hz内的幅频特性呈跟随状态,其相频特性满足相位一致;在LEVT中对地杂散电容越大,误差就越大;CEVT二次分压电阻的取值越大,其传变特性越差、带宽变小。合理选择电阻值,可以修正CEVT的暂态特性。存在杂散电容会使得二次输出电压变小。     

阻容型分压器在脉冲电容器放电特性研究中的应用

该文设计了一种包括脉冲电阻分压器和高压云母电容器的阻容型分压器，用于脉冲电容器放电特性的实验研究。在脉冲电容器充电过程中，高压云母电容器承受高电压；在脉冲电容器放电过程中，脉冲电容器的瞬变电压在脉冲电阻分压器上产生输出电压。通过合理设计阻容分压器的电容、电阻值，可以准确测量脉冲电容器的充电电压和放电波形。该文用阻容型分压器分析了一种脉冲电容器的放电特性。     

电阻分压器电场计算及其结构参数的确定

研究一种电磁式电压互感器的替代装置——电阻分压器,并对其电场进行分析计算以确定其结构参数。本文中利用简单谐变场的有限元方法,计算了几种方案的电阻分压器电场,得到了场中各点复数形式的电位分布,通过比较其幅值误差、相角误差和最大场强值。优化出最佳方案,并分析了该方案幅值误差的频率特性。最后从电路的角度验证了设计计算的正确性。     

用于电池管理系统的高压多路选择器（英文）

提出了一种用于在电池管理系统(BMS)中传输和转换高共模电压的多路复用器.该多路复用器由高压开关和电平移位电路组成.在电平移位电路中,引入电阻分压器和金属层叉指电容两种结构,解决了普通电容器不能承受高电压的问题.提出了一种用于校准电容、电阻失配和参考电压偏差的校准方案.基于0.25μm1P4M 80 V BCD工艺完成该高压多路选择器设计,并用于一款电池监控芯片中.高压多路选择器版图提取的后仿真结果表明:采用电阻分压器方法,最大误差从11.2%降低到1.9%;采用叉指电容方法,最大误差从8.7%降低到2.7%.该高压多路复用器可以传输和转换0-70 V共模电压.     

CVT绝缘试验技术探讨

对CVT的电容分压器的电容及介损现场测量时,直接进行整体试验、正接法电磁单元的影响、自激法泄漏电阻和测量线接触不良所产生的误差的原因进行分析,同时对自激法试验电压的监测方法作了介绍,总结出减少测量误差和预防损坏CVT的测量方法.     

电容器的电压跃变能量转换

本文分析了电容器电压跃变时伴随的冲激电流的能量转换，并以脉冲补偿分压器为例进行了，指出在计算有电容电压跃变的能量损耗时，除计及集中参数的电阻元件的员耗而外，冲激电流在分布电阻及电磁辐射上的能耗不可忽略。     

电容器的电压跃变与能量转换

本文分析了电容器电压跃变时伴随的冲激电流的能量转换，并以脉冲补偿分压器为例进行了讨论，指出，在计算有电容电压跃变的能量损耗时，除计及集中参数的电阻元件的损耗而外，冲激电流在分布电阻及电磁辐射上的能耗不可忽略。     

露天矿直流供电系统杂散电流分析

通过建立露天煤矿电气化铁道简化的均匀分布参数模型，分析了直流杂散电流的分布规律和影响直流杂散电流的主要因素，并提出了抑制杂散电流应采取的有效措施。直流杂散电流的主要影响因素可分为电压因素和电阻因素两个方面。利用本方法分析露天矿杂散电流的分布规律，进而采取有效的抑制措施，减小杂散电流的危害，对保证安全生产具有积极作用。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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