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This dissertation gives a special research in microcomputer relay protection for power transformer of 110kV or below voltage ratings, which based on widely summarizing the theory of power system relay protection and its advanced trend. After analyzing the working character of the transformer in details and absorbing the advantages in other power transformer protection, a scheme which is fit to power transformer of 110kV or below voltage ratings is put forward.

本文在全面介绍和评述电力系统微机保护原理及其发展趋势的基础上，对电力系统中大量应用的110kV及以下各电压等级的变压器保护进行了专门研究，根据这一类电力变压器的运行特点，吸取以往各种保护方法的长处，提出了这类电力变压器保护方案。

PART 1 Electrical and Electronic Engineering Basics UNIT 1 A UNIT 2 A UNIT 3 A UNIT 4 A UNIT 5 A UNIT 6 A UNIT 7 A Electrical Networks ———————————— 3 B Three-phase Circuits The Operational Amplifier ——————————— 5 Logical Variables and Flip-flop —————————— 8 Power Semiconductor Devices —————————— 11 Types of DC Motors —————————————15 AC Machines ———————————————19 Electric Power System ————————————22 B Transistors B Binary Number System B Power Electronic Converters B Closed-loop Control of DC Drivers B Induction Motor Drive B Power System Automation PART 2 Control Theory UNIT 1 A B UNIT 2 A UNIT 3 A UNIT 4 A The World of Control ————————————27 Stability and the Time Response ————————— 30 The Root Locus ————————————— 32 The Transfer Function and the Laplace Transformation —————29 B Steady State————————————————— 31 B The Frequency Response Methods: Nyquist Diagrams ————— 33 The Frequency Response Methods: Bode Piots ————— 34 B Nonlinear Control System 37 UNIT 5 A Introduction to Modern Control Theory B B B PART 3 B B B State Equations Optimum Control Systems Artificial Neural Network Computer Control Technology 42 43 44 Fundamentals of Computer and Networks The Applications of Computers 46 40 38 UNIT 6 A Controllability, Observability, and Stability UNIT 7 A Conventional and Intelligent Control UNIT 1 A Computer Structure and Function UNIT 2 A Interfaces to External Signals and Devices UNIT 3 A PLC Overview PACs for Industrial Control, the Future of Control 1 UNIT 4 A Fundamentals of Single-chip Microcomputer 49 B B PART 4 B B B B PART 5 B B B B PART 6 Understanding DSP and Its Uses Embedded Systems Design Process Control 50 52 53 Fundamentals of Process Control UNIT 5 A A First Look at Embedded Systems UNIT 1 A A Process Control System UNIT 2 A Sensors and Transmitters Final Control Elements and Controllers PID Controllers and Other Controllers Control Panels Control Based on Network and Information Evolution of Control System Architecture Stability of NCSs with Network-induced Delay Virtual Manufacturing—A Growing Trend in Automation Enterprise Resources Planning and Beyond Synthetic Applications of Automatic Technology UNIT 3 A P Controllers and PI Controllers UNIT 4 A Indicating Instruments UNIT 1 A Automation Networking Application Areas UNIT 2 A Fundamental Issues in Networked Control Systems UNIT 3 A Fundamentals of the Database System UNIT 4 A Concepts of Computer Integrated Manufacturing UNIT 1 A Recent Advances and Future Trends in Electrical Machine Drivers B B B System Evolution in Intelligent Buildings A General Introduction to Pattern Recognition Electric Vehicles UNIT 2 A Industrial Robot UNIT 3 A Renewable Energy 2 UNIT 1 A

电路 电路或电网络由以某种方式连接的电阻器，电感器和电容器等元件组成。如果网络不包含能源，如电池或发电机，那么就被称作无源网络。换句话说，如果存在一个或多个能源，那么组合的结果为有源网络。在研究电网络的特性时，我们感兴趣的是确定电路中的电压和电流。因为网络由无源电路元件组成，所以必须首先定义这些元件的电特性。就电阻来说，电压-电流的关系由欧姆定律给出，欧姆定律指出：电阻两端的电压等于电阻上流过的电流乘以电阻值。在数学上表达为： u=iR (1-1A-1)式中 u=电压，伏特；i =电流，安培；R =电阻，欧姆。纯电感电压由法拉第定律定义，法拉第定律指出：电感两端的电压正比于流过电感的电流随时间的变化率。因此可得到：U=Ldi/dt 式中 di/dt =电流变化率，安培/秒； L =感应系数，享利。电容两端建立的电压正比于电容两极板上积累的电荷 q 。因为电荷的积累可表示为电荷增量 dq 的和或积分，因此得到的等式为 u=，式中电容量 C 是与电压和电荷相关的比例常数。由定义可知，电流等于电荷随时间的变化率，可表示为 i = dq/dt。因此电荷增量 dq 等于电流乘以相应的时间增量，或 dq = i dt，那么等式(1-1A-3)可写为式中 C =电容量，法拉。

Can be seen, no overload is the essence of the centrifugal pump, pump shaft power curve peak, or shaft power with the increase of flow rate changes are small, relatively flat power curve that axis, so that the pump shaft power in the dead lift off to zero head (that is, from zero flow to maximum flow rate) are less than equal to the original context of the supporting motive power.

可见，无过载离心泵的实质是指，泵的轴功率曲线有峰值或轴功率随流量的增加而有较小的变化，即轴功率曲线比较平坦，使泵的轴功率在关死扬程到零扬程范围内都小于等于原动机的配套功率。

In fact, power factor from loading side to power room with capacitor bank or reasonably high power factor and penalty of higher KWH price shall make the actual power bill lower than LOW power factor.

下表的计算好象是提高功率因素，降低电流及电压，理论上是节电，但是数据显示不单不节电反而用多了电，但如不算功率因素的话，节电率是27.3%。

There are complex variations in realistic low-voltage power line network topology framework.In order to study the low-voltage power line transmission channel model,a model to describe the power line network channel topology framework is established in terms of basic characteristics of low-voltage power line network in this paper.

低压电力线网络拓扑结构变化复杂，为了研究低压电力线信道传输模型，根据低压电力线网络的基本特点建立了描述电力线网络拓扑结构的模型，利用模型把低压电力信道作为一个过程去描述，建立了节点信号传输函数来推导低压电力线网络的传递函数。

The agitation power consumptions in boiling systems decrease uniformly with the increase of agitation speed, whereas the relative power demand (RPD-the ratio of agitation power input of HEDT for gassed system to that for ungassed system and under the same agitation speed) can maintain at a high level for high gas loadings even when the impeller is operating with a high impeller tip speed. The gas hold-up in the boiling system is much lower than that in the cold gassed system, and the gas hold-up in boiling system increases at first and then decreases with the increase of the agitation power consumption per liquid mass P(subscript m. It implies that the boiling three-phase system has a maximum gas hold-up point. The changes of nucleation site of vapour bubble and the character of suspension of the solid particles with the rotational speed of the impeller are responsible for those behaviors mentioned.

在沸腾条件下，搅拌功率消耗随着搅拌转速的增加有所下降，但HEDT桨具有较高的载气能力，即使在高叶端线速度下，相对功率消耗仍能保持在较高的水平；沸腾体系的气含率随单位质量流体输入功率的增加表现出先增后减的规律，即存在气含率的极大值，蒸汽成核位置和固体颗粒悬浮特性随搅拌功率增加而改变是造成上述行为的主要原因；沸腾体系中的气含率远远低于常温通空气体系。

Sichuan Provincial Foreign Trade Metals and Minerals Import and Export limited liability company mainly engaged in technology transfer and production of complete sets of equipment and raw materials in bulk import and export business, operating the main products are: thermal power generation equipment, hydro-electric power equipment, power transmission equipment, environmental equipment, water treatment Equipment, general machinery, light industrial machinery, construction machinery, grain, oil, food machinery, transport machinery, plastics machinery, chemical machinery, packaging machinery, machine tools, machine tools, measuring tool cutting tools, hand tools, farm tools, rubber processing equipment, telecommunications equipment, system Sugar equipment, compressed air equipment, geological drilling equipment, ceramic equipment, railroad equipment, rolling stock, chemical equipment, industrial Li, teaching equipment, communications equipment, glass equipment, communication cables, power cables, all kinds of special light bulbs, all kinds of Electronic components, all kinds of hardware, all kinds of aluminum, profiles, steel, pig iron, iron alloy, nonferrous metals, ferrous metals, non-metallic mineral products and chemical raw materials, the company is now working with various world-renowned brand manufacturers and agents There is a close business contacts at the same time the company has also developed international financial institutions, loans and government bonds, and other related businesses bidding, so far, I Division in loans from the World Bank, Asian Bank loans in the tender have been repeatedly successful.

四川省外贸五金矿产进出口有限责任公司主要从事技术引进，成套设备和大宗生产原材料的进出口业务，经营的主要产品有：火力发电设备、水力发电设备、输变电设备、环保设备、水处理设备、通用机械、轻工机械、建筑施工机械、粮油食品机械、运输机械、塑料机械、化工机械、包装机械、机床、机床工具、量具刃具、手工工具、农具、橡胶加工设备、邮电设备、制糖设备、空气压缩设备、地质钻探设备、搪瓷设备、铁道设备、机车车辆、化工仪器、工业黧器、示教仪器、通讯仪器、玻璃仪器、通信电缆、电力电缆、各种特种灯泡、各种电子元件、各种小五金、各种铝材、型材、钢材、生铁、铁合金、有色金属、黑色金属、非金属矿产品和化工原料等，公司现与多个世界著名品牌的生产厂和代理商有着密切的业务往来；同时公司还开展国际金融机构贷款和国债项目等相关的招投标业务，迄今为止，我司在世界银行贷款、亚洲银行贷款等的招标中曾先后多次中标。

Fortunately, our practice has proved that the establishment of a scientific system, in which public power supervision is implemented in village communities to regulate the exercise of power and monitor the efficiency of power exercise, is an effective measure to prevent and correct the deviances and disorders which arise out of the exercise of power in grass-root communities in rural areas.

实践证明，从农村实际出发，构建科学的村社区公共权力监督机制，约束村级权力运行过程，监控权力运行效益是防止和纠正农村基层权力运行过程中出现偏误与紊乱的有效手段。

The rising power of Japan alarmed the United States and the European powers. In order not to be threatened, the United States invited 8 countries to attend a conference in Washington in 1921, and later signed the 'Four-Power Pact','Five-Power Pact' and 'Nine-Power Pact'. The main objectives of these were to stop the naval race and to maintain a new order in East Asia and in the Pacific region, so as to avoid international conflicts.

日本崛起为世界强国，令美国及欧洲列强大为震惊，为了免受威胁，美国遂於1921 年邀请其他8国出席华盛顿召开的会议，其后签订了《四国公约》、《五国公约》及《九国公约》，目的是停止海军军备竞赛、稳定东亚及太平洋的新秩序，以及避免国际间的衡突。

The following functions can be realized: Measuerment:the effective values of three phase current and voltage, power frequency, active power, reactive power, power factor etc. Motor control: direct starting, converse starting, star and triangle starting, self-starting. Protection:thermal overload protection, current leakage protection, open-phase protection, three-phase unbalance protection, over voltage protection, loss voltage protection, low load protection and fault warning and fault dates memory. Communication: communication of the computer in control room and the microcomputer monitor in the spots is realized by the interface of RS-485. The motor is not only controlled in the spots but also in control room. The dates, information and some functions are shared by the spots and control room too.

该电动机监控器以80C196KC单片机为核心，通过采样三相电流﹑电压信号来实现以下功能：三相电流﹑电压有效值，电网频率，有功功率，无功功率及功率因数等的测量；对电动机实现直接、正反转、星三角及自起动控制；对电动机实现热过载、漏电、断相、三相不平衡、过压、欠压及轻载保护，对故障进行报警及数据记忆；通过RS-485串行接口与中央控制室计算机实现通信功能，对电动机既可本地，也可远程控制；实现控制现场与控制室之间数据、信息、功能共享。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。