Today , most applications of liquid crystal are depend on voltage - dependent birefringence effect . voltage - dependent birefringence of liquid crystal is widely used because of many merits . ( l ) its applicable spectral range is extraordinarily broad 液晶的电控双折射特性之所以应用广泛，主要是因为它有以下几个独特的优点： ( 1 )可应用光谱范围特别宽。
A protective method based on voltage - frequency - converter and additional dc measuring the insulation between monitor wire and ground lines of hv double screen cable is developed and realized by analog and digital circuits 通过分析6kv电缆绝缘监视保护的特点，提出了在高压电缆监视线与接地线之间附加直流电源并利用v / f转换实现监视保护的新方法，设计了相应的电路。
Schottky barrier diode is a kind of majority carrier device , using the contact barrier formed between metal and semiconductor to work . it has the advantages of low turn - on voltage and high response frequency , compared with pn junction diodes 肖特基二极管是利用金属与半导体之间接触势垒进行工作的一种多数载流子器件，与普通的pn结二极管相比，它具有正向导通电压低，响应速度快等优良特性。
Aiming at present problems , the author also studied the hysteresis control system based on voltage vector control and its corresponding scheme . in chapter one , the harmonic problems and the development of active power factor filter are discussed 又针对目前存在的问题，研究了基于电压矢量控制的滞环控制系统及方案，其基本内容如下：本文第一章阐述了谐波问题及其危害，回顾了有源电力滤波器的发展情况。
The conical insulator high 15 cm , the diameter of top is 5cm and that of the bottom is 35cm . the insulator is operated for more 300 times on voltage more 600kv , and maximum voltage is 750kv . the operated is stability and no surface flashover phenomenon is happened 锥形绝缘子高15cm ，锥底直径35cm ，锥顶直径5cm ，实验结果表明满足设计要求，在600kv以上工作300多次，最高电压达750kv ，运行稳定，未发生沿表面闪络现象。
The feasibility and effectiveness of the iddt testing are both validated by experiments . at last , transistor bridging faults are simulated based on iddq testing and gate bridging faults and stuck - at faults based on voltage testing through detaching a pattern pair into two independent patterns 最后，把一个输入向量对看成两个独立的向量，分别采用稳态电流测试方法和电压测试方法模拟桥接故障的晶体管级故障和桥接故障的门级故障及固定故障。
Many international companies have put their pfc chips on the markets , such as mc33262 , mc34262 , l6561 , l6562 , ml4812 etc . in this paper , we studied on critical current mode active power factor correction technology , and did a detailed analysis and design on voltage reference circuit and analog multiplier circuit 国际上已经出现了一些有源功率因数校正芯片,如onsemi公司的mc33262 、 mc34262 , st公司的l6561 、 l6562 , microlinear公司的ml4812等产品。本文研究了有源功率因数校正技术中的临界导通模式的基本原理,并对其中的电压基准源和模拟乘法器做了详细的分析和设计。
Through analyzing the mathematical model of two winding transformer , the effect after on - load tap changing on voltage and reactive power balance at each side , effect of shunt capacitor compensation on voltage and reactive power balance in substation the relation between transformer tap adjusting and shunt capacitor switching in practical grid operation were discussed 摘要通过对两卷变压器的数学模型进行分析，讨论了两卷变压器抽头调整后，变电站各侧电压及无功功率的变化；无功补偿对变电站各侧电压及无功功率的影响；实际电网生产运行中，无功补偿与变压器抽头的配合调整。
This thesis carries out studies around the impact of load characteristics on voltage stability - the key problem of power system voltage stability analysis . the impact of load characteristics on static voltage stability is analyzed with the methods based on v - p - and - v - q curves , and the dynamic voltage stability of different loads in the context of both small disturbances and large disturbances is studied with the method of time domain simulation 本文围绕电力系统电压稳定性分析中的关键问题-负荷特性对电压稳定性的影响这一问题展开研究,采用v - p , v - q曲线分析法分析了负荷特性对静态电压稳定性的影响,并采用时域仿真法研究了大扰动和小扰动下负荷的动态电压稳定性。
Firstly , the thesis briefly reviews the history of voltage and reactive power control technology , focusing on the defects of the equipment in use . then , with the theoretical analysis and the discussion on voltage and the characteristic of power system as well as the basic principle of voltage and reactive power control , the thesis makes a research on the character of voltage and reactive power control and interprets the controlling regularity of substation . in addition , with the consideration of the changes of transformer tips and the combined influence of capacity groups and reactive power and voltage , the thesis makes adjustment suggestion to the different operating - zones of voltage and reactive power 本文从降低网损和提高变电站自动化水平着眼，对变电站电压无功控制应用方面的问题进行了研究，本文首先简要回顾电压无功控制的发展概况，着重指出了现有电压无功控制装置的缺陷；通过理论分析，在讨论电力系统电压、无功调节特点以及电压无功总体控制原则的基础上讨论了变电站电压、无功控制特性以及控制原理，给出了变电站电压无功的控制规律；考虑了变压器分接头的变化及电容器组的投切对无功和电压的综合影响,针对电压、无功的各种运行控制区域给出了相应调节策略。
