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1、精品文档，仅供学习与交流，如有侵权请联系网站删除第一章第一节电力系统基本结构Part 1 Basic Construction of Electric Power SystemBasic Concepts of Electric Power System电能是一种理想的能力形式，便于传输和使用，而且很清洁，对环境和大气无污染，因此自被发现以来，电能发展迅速并且利用广泛。电能的产生、输送和消耗过程就在这一被称为电力系统的整体化系统中实现。Electricity is an ideal energy form, which is convenient to deliver and use, and
2、 is clean without polluting our environment and atmosphere. The generation, delivery and consumption of electricity are realized in an integrated system which is called electric power system or power system.一个电力系统包括三个基本部分：发电系统、输电系统和配电系统，如图1-1所示。An electric power system consists of three principal di
3、visions: power generation, power transmission system, and power distribution systems, as shown in Fig.1.1图1-1电力系统的三个基本部分用户从电力系统取用的所有电能都是在某种形式的电厂（或者称作电站）中产生的。发电是整个电能利用过程的第一环节。All the electricity the consumers take from the power system is generated in a power plant, or called power station, of some k
4、ind. Power generation is the first stage of the whole progress of the utilization of electric energy.输电系统连接发电和配电系统，并经过网络互连通向其他电力系统。配电系统在执行电压变换和开关功能的变电站将所有单个负荷接连到输电线路。Transmission systems are the connecting links between the generation plants and the distribution systems and lead to other power syste
5、ms over interconnections. A distribution system connects all the individual loads to the transmission lines at the substations which perform voltage transformation and switching functions.地处负荷区的附近的小型电厂，通常直接连接到中压输电系统或配电系统。Small generating plants located near the load are often connected to the subtra
6、nsmission or distribution system directly.通常，在输电系统水平上形成相邻电力系统间的互联。Interconnection to neighboring power systems are usually formed at the transmission system level.因而整个电力系统包括多个电源和若干层次的输电网络。这提供了高度的结构化冗余，使系统能够承受罕见的意外事故而不会中断对用户的供电。The overall system thus consists of multiple generating sources and sever
7、al layers of transmission networks. This provides a high degree of structural redundancy that enables the system to withstand unusual contingencies without service disruption to the consumers.第二节 电力系统典型的网络拓扑结构Part 2 Typical Topologies of Electric Power System构成电力系统的设备，其布局取决于当地的负荷增长方式，并且随时可能重新调整。The
8、equipments which form an electric system are arranged depending on the manner in which load grows in the area and may be rearranged from time to time.然而，也可以采取办法对系统进行分类。以下列举三类：辐射状系统、环状系统和网状系统。However, there are certain plans into which a particular system design may be classified. Three types are ill
9、ustrated: the radial system, the loop system and the network system.如图1-2所示，在辐射系统中，线路从电源呈树状向外延伸。打开任一段线路都会导致一个或多个负荷停电。In a radial system, as shown in Fig. 1.1, the lines form a “tree” spreading out from the power source. Opening any line will result in interruption of power to one or more of the load
10、s.环状系统如图1-3所示。这样接线，即使一条线路退出运行，仍能保证给所有负荷供电。The loop system is illustrated in Fig. 1.2. With this arrangement all loads may be served even though one line section is removed from service.图1-4所示的是同样的负载由网状方式供电。这样设计，保证了每个负荷有两条或多条线路为其供电。Fig. 1.3 shows the same loads being served by a network. With this ar
11、rangement each load has two or more circuits over which it is fed.通常将配电线路设计成辐射状或环状，但是大多数高压输电线路则按网状布局，主要电力系统的互联形成由多个线路段组成的网络。Distribution circuits are commonly designed so that they may be classified as radial or loop circuit. The high-voltage transmission lines of most power systems are arranged as
12、networks. The interconnection of major power systems result in networks made up many line sections.第三节 大多数电力系统的特点Part 3 Characteristics of Most Power System第一个完整的电力系统是直流系统。交流输电的发展，促成了交流电力系统的产生。由于下列原因，交流系统已经完全取代直流系统。The first complete electric power system was a direct current (DC) system. The develo
13、pment of alternating current (AC) transmission led to AC electric power system. The AC system had won out over the DC system for the following reasons:（1）交流系统易于转换电压等级，因而提供了以不同电压水平进行发电、输电和用电的灵活性。i ) Voltage levels can be easily transformed in AC systems, thus providing the flexibility for use of diff
14、erent voltage for generation, transmission, and consumption.（2）与直流电机相比，交流电机要更加简单和便宜。ii) AC electric machines are much simpler or cheaper than DC electric machines.电力系统的大小和结构组成可能不同。然而，它们有相同的基本特点Electric power systems vary in size and structural components. However, they all have the same basic charac
15、teristics:（1）电力系统都是由基本运行在恒定电压的三相交流系统构成。发电和输电设备都是三相元件。工业负荷总是三相负载；单相居民负荷和商业在各相之间均匀分配，以有效地构成平衡的三相系统。i) Are comprised of three-phase AC systems operating essentially at constant voltage. Generation and transmission facilities use three-phase equipment. Industrial loads are invariably three-phase; single
16、-phase residential and commercial loads are distributed equally among the phases so as to effectively form a balanced three-phase system.（2）都使用同步电机发电。ii) Use synchronous machines for generation of electricity.（3）经过相当远距离的传输为大面积的用户供电。这要求输电系统的子系统运行在不同的电压水平。 iii) Transmit power over significant distance
17、s to consumer spread over a wide area. This requires a transmission system comprising subsystems operating at different voltage levels.第四节 电力系统的发展完成有用工作的能源的开发是工业发展的关键，而工业发展时各地生活水平不断提高所必需的。电力系统是在应对该挑战中扮演重要角色的转换和运输能量的工具之一。按照某些标准，该产业是世界上最大的产业。Development of source of energy to accomplish useful work is
18、 the key to industrial progress which is essential to the continual improvement in the standard of living of people everywhere. The electric power system is one of the tools for converting and transporting energy which is playing an important role in meeting this challenge. The industry, by some sta
19、ndards, is the largest in the world.19世纪70年代后期弧光灯用于灯塔和街道照明，标志着电能商业应用的开始。The commercial use of electricity began in the late 1870s when arc lamps were used for lighthouse illumination and street lighting.第一个完整的电力系统在纽约建成，于1882年9月开始运行。这是一个直流系统。这是即将发展成世界上最大的产业之一的，电力行业的开端。The first complete electric powe
20、r system was built in New York City which began operation in September 1882. This was a DC system. This was the beginning of what would develop into one of the largest industries in the world.交流系统的发展于1885年始于美国。1890年，美国第一条交流输电路投运。最初的输电线路是单相的。随着多相系统的发展，交流系统显得更加具有吸引力。之后，交流输电尤其是三相交流输电逐渐取代了直流系统。The devel
21、opment of AC systems began in the US in 1885. The first AC transmission line in the US was put into operation in 1890. The first transmission lines were single-phase. With the development of poly-phase systems, the AC system became even more attractive. Thereafter, the transmission of electric energ
22、y by alternating current, especially three-phase alternating current, gradually replaced DC system.交流输电的早期，运行电压级迅速提高。例如，在美国，1890年首条交流线路运行在3.3kV。1907年电压升到100kV,1913年升到150 kV，1923年220 kV，1926年244 kV，1936年达到287 kV。1953年出现了第一条345 kV线路。1965年第一条500 kV线路投运。四年后即1969年，首条765 kV投运。In the early days of AC power
23、 transmission, the operating voltage increase rapidly. For instant, in the United States, in 1890 the first line was operated at 3.3kV. Voltage rose to 100kV at 1907, 150kV in 1913, 220kV in 1923, 244kV in 1926, and 287kV in 1936. In 1953 came the first 345kV line. The first 500kV line was operating
24、 in 1965. Four years later in 1969 the first 765kV line was placed in operation.由于电力系统起始于孤立系统并且只是逐渐地扩展到覆盖全国，所以直到1917年，电力系统通常以独立单元形式运行。鉴于大批量的供电需求以及日益增长的可靠性要求，引起了相邻系统的互联。互联已经发展到这样的程度，功率在不同电力公司的系统之间交换已经成为惯例。Until 1917, electric systems were usually operated as individual units because they started as i
25、solated systems and spread out only gradually to cover the whole country. The demand for large blocks of power and increased reliability suggested the interconnection of neighboring systems. Interconnection has increased to the point where power is exchanged between the systems of different companie
26、s as a matter of routine.第二章 发电第一节 发电概述Electric Power GenerationPart 1 About Power Generation发电是电能应用的第一步。电力系统用同步电机产生电能，换句话说，同步发电机是电力系统中电能的只要来源。作为由涡轮机驱动的交流发电机，同步电机是将机械能转化为电能的设备，其功率范围高达1500MW。原动机将一次能源转化为机械能，随后由发电机转化为电能。Power generation is the first stage of electric energy application. Power system us
27、e synchronous machines for generation of electricity, in other words, synchronous generators form the principle source of electric energy in power systems. The synchronous machine as an AC generator driven by a turbine is the device which converts mechanical energy to electrical energy, in powers ra
28、nging up to 1500MW. Prime movers convert the primary sources of energy to mechanical energy that is, in turn, converted to electrical energy by synchronous generator.在将一台发电机接到无穷大母线或与另一台发电机并联之前，必须使其同步。当满足下列所有条件时，称为发电机同步:Before connecting a generator to an infinite bus (or in parallel with another gen
29、erator), it must be synchronized. A generator is said to be synchronized when it meets all the following conditions:(1)发电机频率与系统频率相等。(2)发电机电压幅值与系统电压幅值相等。(3)发电机电压与系统电压同相。(4)发电机相序与系统相序相同。i) The generator frequency is equal to the system frequency.ii) The generator voltage is equal to the system voltage
30、.iii) The generator voltage is in phase with the system voltage.iv) The phase sequence of the generator is the same as that of the system. 第二节 水电Part 2 Hydropower Generati利用流动的水来生产电能称为水力发电或水电。水力发电或水电是一种很重要的能源。依靠与同步发电机相连接的水轮机，水电站将移动的水的能量转换为电能。When flowing water is captured and turned into electricity
31、, it is called hydroelectric power or hydropower. Hydropower power, also called water power, is a type of important common power source. Hydropower generating stations convert the energy of moving water into electrical energy by means of a hydraulic turbine coupled to a synchronous generator.水电优于其他能
32、源但面临独特的环境问题挑战。Hydropower offers advantages over other energy sources but faces unique environmental challenges.优点：水电由水供给，因此是清洁的燃料源。水电不会污染空气。水电是本土能源，许多国家都能生产。水电靠的是太阳控制的水循环，因而是一种可再生能源。水电一般可满足需求，工程师可以根据需要去控制流过水轮机的水量来产生电能。Advantages: Hydropower is fueled by water, so its a clean fuel source. Hydropower
33、doesnt pollute the air. Hydropower is a domestic source of energy, produced in the many countries. Hydropower relies on the water cycle, which is driven by the sun, thus its a renewable power source. Hydropower is generally available as needed; engineers can control the flow of water through the tur
34、bines to produce electricity on demand.除了清洁的电能之外，水电厂还提供其他效益。这些效益可能包括：广泛的休闲娱乐机会、供水及洪水控制。Hydropower plants provide benefits in addition to clean electricity. These benefits may include a variety of recreational opportunities, water supply and flood control.缺点：水电会影响水质及水流。水电厂会导致水中的氧气溶解度降低-（这是）一个对岸边生存环境有
35、害的问题。维持水电设施的水流最小，对岸边生存环境的存续也是不利的。水电厂会受干旱影响。没水时不能发电。新的水电设施影响当地环境，并且可能与土地的其他用途冲突。其他可选用途可能比发电更有价值。Disadvantages: Hydropower can impact water quality and flow. Hydropower plants can cause low dissolved oxygen levels in the water, a problem that is harmful to riverbank habitats. Maintaining minimum flows
36、 of water downstream of a hydropower installation is also critical for the survival of riverbank habitats. Hydropower plants can be impacted by drought. When water is not available, the hydropower plants cant produce electricity. New hydropower facilities impact the local environment and may compete
37、 with other uses for the land. Those alternative uses may be more highly valued than electricity generation.大多数现有水力资源储量已完全开发。例如，在美国，水电在全部电力中所占的比例不到20%，并且，因为大多数可用的水电资源已被开发，该百分数还会下降。The hydraulic resources of most modern connotations are already fully developed. For instance, in the United States, wat
38、er power accounts for less than 20% of the total and that percentage will drop because most of the available sources of water power have been developed.第三节 火电（热电）Part 3 Thermal Generation热电厂利用煤、石油或天然气这类化石燃料燃烧产生的热量产成电能。大多数电站的额定值在200-1500MW之间，以实现大型设施的高效率和经济性。这样的电站必须重视其高度复杂性和庞大的尺寸。Thermal generating st
39、ations produce electricity from the heat released by the combustion of fossil fuels, such as coal, oil, or natural gas. Most stations have ratings between 200 MW and 1500 MW so as to attain the high efficiency and economy of a large installation. Such a station has to be seen to appreciate its enorm
40、ous complexity and size. 热电厂通常位于河流或湖泊附近，这是因为需要大量的冷却水在蒸汽从汽轮机排除时将其冷凝。Thermal stations are usually located near a river or lake because large quantities of cooling water are needed to condense the steam as it exhausts from the turbines.由于涡轮机自身所固有的低效率，热电厂的效率一般都很低。The efficiency of thermal generating sta
41、tions is always low because of the inherent efficiency of the turbines. 目前大部分电力是在蒸汽轮机电厂产生的。在蒸汽轮机电厂应用最为广泛的是煤。20世纪70年代初期，很多电厂转向石油，但面对石油价格的持续上涨及降低依赖进口石油的必要性，在所有可能的地方都出现了从石油到煤的回归。蒸汽轮机被用来在系统峰荷时进行小幅短时调节。Now most of the electric power is generated in steam-turbine plants. Coal is the most widely used fuel
42、for the steam plants. Many plants converted to oil in the early 1970s, but in the fact of the continuous escalation in the price of oil and the necessary of reducing dependence on foreign oil, reconversion from oil to coal has taken place wherever possible. Gas turbines are used to a minor extent fo
43、r short periods when a system is carrying peak load. 第四节 核电Part 4 Nuclear Generation核电站利用核反应堆释放出的热量发电。当一个原子核分裂为两个时（称为核裂变过程），会释放大量能量。Nuclear stations produce electricity from the heat released by a nuclear reaction. When the nucleus of an atom splits in two (a process called atomic fission), a consid
44、erable amount of energy is released.核电站与传统的热电厂很相似。总效率也相近（介于30%-40%），且必须有冷却系统，因而核电站也建于河流或湖泊附近。在干旱地区要建冷却塔。A nuclear station is similar to a conventional thermal station. The overall efficiency is also similar (between 30 and 40 percent), and a cooling system must be provided for it. Consequently nucle
45、ar stations are also located close to rivers and lakes. In dry areas, cooling towers are installed. 以铀为燃料的核电厂，负责应对持续增长的负荷份额，但是其建设缓慢且不确定，原因包括：难以增加资金满足急剧增长的建设成本要求，不断增加的安全要求会导致重新设计，公众对电站运行的反对，以及经营许可的迟缓。Nuclear plants fueled by uranium account for a continually increasing share of the load, but their co
46、nstruction is slow and uncertain because of the difficulty of raising capital to meet the sharply rising cost of construction, constantly increasing safety requirements which cause redesign, public opposition to the operation of the plants, and delays in licensing. 铀的储量有限，但是美国又禁止快速中子增殖反应堆，这大大扩展了欧洲基于
47、铀的能源开发。核聚变是未来的重大希望。随着商业规模的可控聚变反应变得切实可行，它将持续发展并且可能接替直接燃料一个用。例如，为了给航空器和长途运输车保留燃料（包括石油和由煤合成的燃气），有可能使用电动汽车。最后，不论用哪种方法来产生能量，保护环境都是相当重要的。The supply of uranium is limited, but the fast breeder reactors now prohibited in the United States, have greatly extended the total energy available from uranium in Eur
48、ope. Nuclear fusion is the great hope for the future. As a controllable fusion process on a commercial scale become feasible, it will continue to grow and take over the direct fuelapplications. For instance, the electric car will probably be used in order to reserve the fossil fuels (including petroleum and gas synthesized from coal) for aircraft and long-distance trucking. Fi