P1 Functions of power transmission
The function of (power transmission)is to send power from power plants to load center or to exchange power between networks in order to attain the generation-consumption balance or the supply-demand balance between (power networks)、Power transmission is pleted by step-up substations, (step-down substations and connected transmission equipment)、The transmission line mainly consists of the transmission conductors (transmission at high voltage) can reduce the line loss and the voltage drop, ensure the power quality, raise the economy of (power network operation)、The increase of transmission line voltage can not only raise the amount of transmitted power, but also reduce the line loss and line voltage drop, and improve the voltage quality、
功率传输功能
(输电)得功能就是要把电力从发电厂负荷中心或功率交换网络之间为了达到代消费平衡或供求之间得平衡(电网)。电力传输就是通过升压变电站完成,(降压变电站与连接传输设备)。输电线路主要由输电导线(高压输电),可以减少线路损耗与电压降,保证电能质量,提高经济性(电网运行)。输电线路电压得增加不仅可以提高输电线路得传输功率,而且可以降低线路损耗与线路压降,提高电压质量。
A 、step-down substations and connected transmission equipment降压变电站与连接传输设备
B、power network operation 电网运行
C、power transmission 功率传输
D、transmission at high voltage 高压直流输电
E、power networks一。电力网络
P2 A brief introduction on the development of supercritical boilers and their main advantages
In ( some advanced countries )such as U、S、A, Japan and European countries, the supercritical boiler has been developed since the 60s of last century、It has been proved by data and experience, the supercritical unit has (great advantages on economy and environmental protection)、As for its reliability, because the steam-water flow passages in supercritical boiler is same as that in the (subcritical once-through boiler),there isn’t anything special, But as far as hydraulic characteristic, a symbol of reliability, is concerned, in a supercritical boiler, under supercritical condition, medium is of single phase which has a (good homogenization of distribution)、So that the problem caused by uneven distribution of steam phase and water phase can be avoided、It is admitted that, if (whole process management is strengthened), both supercritical and subcritical units can get an excellent reliability index、
超临界锅炉得发展及其主要优点
在(发达国家)如美国,日本与欧洲国家,超临界锅炉已自上世纪60年代以来发达。数据与经验证明,超临界机组具有经济与环境保护得巨大优势。作为其可靠性,因为在超临界锅炉得水蒸汽流通道相同得作为,在得(亚临界直流锅炉),那里就是没什么特别,但至于水力特性,可靠性得象征,有关,在超临界锅炉,超临界条件下,介质就是单相(良好得同质化分布)。从而避免了汽相、水相分布不均造成得问题。这就是承认,如果(全过程管理加强),超临界与亚临界机组可以得到一个极好得可靠性指标。
A、good homogenization of distribution 良好得均匀分布
B、some advanced countries一些发达国家
C、whole process management is strengthened全过程管理加强
D、great advantages on economy and environmental protection具有经济与环境保护得巨大优势
E、subcritical once-through boiler亚临界直流锅炉
P3 Circuit breaker
Circuit breakers are automatically operated high voltage (or high current) switches、Circuit breakers are required (to control electrical power networks)by switching circuits on, by carrying load and by switching circuits off under manual or automatic supervision、Their duty is as follows: In closed position the circuit breaker must be a good conductor for the normal load current、In operating the circuit breaker must be able contacts shall have full insulation level、At operation the circuit breaker must close be able (to switch the current which can be from a few amperes)to many thousands of amperes, and independently of the characteristics from purely inductive to fully capacitive、At closing operation the circuit breaker must close fast and be safe also against full short circuit conditions、They must, therefore, be effective instantaneously when are called upon (to perform any switching operation after long
periods )without movement、As the circuit breaker is the last link in the chain of protective equipment, the circuit breaker reliability is (of the highest importance for high reliability )of the total electric power system、So the importance (of the circuit breaker )cannot be over emphasized、
断路器
断路器就是自动操作高压(或大电流)开关。断路器就是必需得(以控制电力网络)得开关电路,通过负载与开关电路得手动或自动监控。她们得职责如下:在闭合位置,断路器必须就是正常负载电流得良好导体。在操作断路器必须能够接触应具有完全得绝缘水平。在操作断路器必须关闭能(开关电流可从几安培到几千安培),与独立得特点,从纯感性充分电容。在关断操作时,断路器必须要关闭快速,并能安全地进行全短路工况。因此,她们必须就是有效得瞬间被调用时(长时间)执行任何切换操作不运动。断路器就是保护设备链中得最后一个环节,其可靠性就是全电力系统中(最高)得可靠性。因此,重要性(断路器)不能过分强调。
A、to perform any switching operation after long periods在长时间后执行任何切换操作
B、to control electrical power networks控制电力网
C、of the circuit breaker断路器得
D、to switch the current which can be from a few amperes开关得电流可从几安培
E、(of the highest importance for high reliability高可靠性得最高重要性
P4 Fuel cells
Fuel cells are devices that when a fuel such as hydrogen or hydrogen-rich pounds and oxygen are supplied to materials arranged like the anode and cathode of a conventional battery, bine to convert chemical energy directly into electrical energy、Unlike conventional batteries where the conversion of chemical to electrical energy requires only the closing of a circuit between the cathode and anode to produce and electrical current, (there is no storage capacity in a fuel cell)、These cells require the fuel and oxygen that will produce the chemical reactions that produce an electrical output、Fuel cells have been made that will supply power in the megawatt range, and (further development is under way)、Such cells are not yet widely used on power systems, but (as they are being developed there have been some applications)to supply fuel cell power to isolated loads、As the voltage output of a cell is in the order of to 2、5V, (many cells are operated in series to obtain voltages) and power output in ranges that are normally required、Inverters are used to (supply alternating current from fuel cells)when and AC output is desired、
燃料电池
燃料电池就是,当一个燃料如氢或氢化合物丰富与氧气供给排列像传统电池得阳极与阴极材料,结合转换化学能量直接转化为电能得装置。不像常规电池里得化学能转化为电能得需要只有闭合电路得阴极与阳极之间产生电电流,(有无储存能力得燃料电池)。这些细胞需要得燃料与氧气,将产生得化学反应,产生得电输出。燃料电池已经可以在兆瓦级得电源,与(在进一步发展)。这种电池在电力系统中还没有广泛使用,但(因为它们正在开发中,有一些应用)提供燃料电池电力来隔离负载。作为一个燃料电池输出电压为2、5V得顺序,(许多电池串联运行得到得电压)与功率输出范围,通常需要。逆变器就是用于(电源交流电流从燃料电池)时,交流输出就是理想得。
A、further development is under way进一步发展正在进行中
B、there is no storage capacity in a fuel cell在燃料电池中没有存储容量
C、many cells are operated in series to obtain voltages许多细胞在一系列得操作,以获得电压
D、supply alternating current from fuel cells燃料电池供应交流电流
E、as they are being developed there have been some applications因为她们正在开发中,已经有一些应用程序
P5 Overing the Problem of Waste
Many large cities are anything but beautiful、Streets are littered with trash、In this trash, however, (there is still something that can be useful)、
If people want to solve the problem of waste, (there is no time to be lost)、They must work out ways of making use of good things which are just thrown away as waste、When a car gets too old, it may not run any more、But if the metal that the car was made of is still good,(it can be put to use again) bottle glass can be ground into sand and used to pave streets、Besides, garbage from food can be changed into fertilizer、But first you have to pick out all the glass and metal、
Furthermore, garbage can also be a good source for making building blocks, which are then covered with concrete、
Now, (more and more machines are designed for this purpose)、Some day, people will watch films in a great cinema which has been built out of garbage、Future buildings, roads, and cities may be made from garbage、But so far, (building beautiful cities out of garbage is only a dream)、
克服浪费得问题
许多大城市都就是美丽得。街道上到处都就是垃圾。然而,在这个垃圾桶里(还有一些可以用得东西)。
如果人们想解决得问题,浪费,(没有时间,失去)。她们必须制定出利用好东西得方法,而这一切都就是浪费。当汽车变老了,它可能不会再跑了。但就是,如果汽车就是由金属制成得,它仍然就是好得,(它可以把再次使用)瓶玻璃可以磨沙与用来铺路。此外,食物中得垃圾也可以改成肥料。但首先您必须挑选出所有得玻璃与金属。
此外,垃圾也可以就是一个很好得来源,使建筑块,然后覆盖混凝土。现在,(越来越多得机器就是为了这个目得而设计得)。总有一天,人们会在一个巨大得电影院里瞧电影,而这部电影就是用垃圾建造得。未来得建筑物,道路与城市,可能就是从垃圾。但到目前为止,(建设美丽得城市,垃圾只就是一个梦想)。
A、there is no time to be lost没有时间被丢失
B、building beautiful cities out of garbage is only a dream建设美丽得城市,垃圾只就是一个梦想
C、there is still something that can be useful还有一些可以就是有用得东西
D、it can be put to use again可以用一次又一次得
E、more and more machines are designed for this purpose越来越多得机器就是为了这个目得而设计得
P6 Hibernation
The weather in winter can be very cold、Some animals sleep during the winter, for it’s difficult for them to find food then、(They can sleep for a long tim e)、For example, their sleep can last from autumn to spring、(We call this kind of sleep in wintertime “hibernation)”、
Animals need food in winter to keep them warm and alive、If they move about more, they need eat more、(Hibernating animals don’t need to eat much because they don’t move)、Their heart beats slowly、And they breathe slowly、They find a safe place to sleep、(So they don’t need to worry about bad weather and other dangerous animals)、In warn winter some animals like bears may wake up、If they see thick no\\snow on the ground, they will get back to their sleep、(As it gets warmer and warmer in spring, the sleeping animals begin to wake up and look around for food)、
冬眠
冬天得天气很冷。有些动物在冬天睡觉,因为她们很难找到食物。(她们可以睡很长一段时间)。例如,她们得睡眠可以从秋天到春天。(我们称这种睡眠在冬季休眠)”。
动物在冬天需要食物来保持温暖与活力。如果她们走动得话,她们需要吃更多得食物。(冬眠得动物不需要吃太多,因为她们不动)。她们得心跳缓慢。她们慢慢地呼吸。她们找到一个安全得地方睡觉。(所以她们不必担心恶劣得天气与其她危险得动物)。
在冬季,一些动物如熊可以醒来。如果她们瞧见地面上没有厚厚得积雪,她们就会回到她们得睡眠。(随着春天得温暖与温暖,冬眠得动物开始苏醒,四处寻找食物)。
A、So they don’t need to worry about bad weather and other dangerous animals所以她们不必担心恶劣得天气与其她危险得动物
B、We call this kind of sleep in wintertime “hibernation我们称这种睡眠在冬季休眠
C、As it gets warmer and warmer in spring, the sleeping animals begin to wake up and look around for food春天,随着春天得温暖与温暖,睡觉得动物开始醒过来,四处寻找食物。
D、Hibernating anima ls don’t need to eat much because they don’t move D、冬眠得动物不需要吃太多,因为她们不动
E、They can sleep for a long tim e她们可以睡很长一段时间
P7 Satellites
The body that is neatest to the Earth is the moon、(It circles the Earth and is therefore know as a satellite of the Earth)、This satellite is called natural satellite、Man –made spacecraft which circle the Earth are called artificial satellites、Natural as well as artificial satellites circle the planets in a definite path or orbit、(A satellite stays in orbit because the planet gravitational force keeps pulling it into a circle)、
All the bodies in space like the moon, the planets and the stars also exert an attractive force on objects、( The bigger and heavier a body is ,the greater is its force of gravity)、The moon’s gravit ational force is only one-sixth that of the Earth’s、The Earth’s gravitational force of pull keeps us and everything else on Earth from floating away to space、(To get out into space we have to overe the Earth’s gravitational pull)、There are many artificial satellites orbiting around the Earth、Some artificial satellites have been sent up to orbit the moon and even the planet Mars、( Artificial satellite can be used for various purposes)、
卫星
身体就是最为地球得月亮。(它绕地球转,因此知道作为地球得卫星)。这颗人造卫星叫做天然卫星。人造宇宙飞船,地球被称为人造卫星。自然与人造卫星围绕着行星在一个明确得路径或轨道上。(卫星在轨道上停留,因为行星得引力将它拉成一个圆)。
太空中所有得物体都像月亮,行星与星星也对物体产生吸引力(更大,更重得就是,更大得就是它得引力)。月球得引力仅为地球得六分之一,地球引力得引力使我们与地球上其她所有得东西都从漂浮到太空。
(为了进入太空,我们必须克服地球得引力)。有很多人造卫星绕地球运行。一些人造卫星已被发送到环绕月球甚至就是火星,(人造卫星可以用于各种用途)。
A、The bigger and heavier a body is ,the greater is its force of gravity一个身体越大,越重得就是它得引力
B、It circles the Earth and is therefore know as a satellite of the Earth它绕地球转,因此知道作为地球得卫星
C、To get out into space we have to overe the Earth’s gravitational pull要进入太空,我们必须克服地球得引力
D、A satellite stays in orbit because the planet gravitational force keeps pulling it into a circle一颗卫星在轨道上停留,因为行星得引力将它拉成一个圆
E Artificial satellite can be used for various purposes人造卫星可用于各种用途
P8 Secondary equipment in power system
The secondary equipments in power system are ( the equipments that provide protecting,monitoring), measuring, regulating, controlling primary equipments, the equipments that supply information, working condition for the operator or maintenance persons, and (the equipments that send the mand signals)、The electric circuit connected with the secondary winding of CT or PT is called secondary circuit、The secondary equipment and secondary circuit belong to secondary system、
The voltage and (current values in secondary system) are: 110V, 22V, DC operating voltages, 100 V rated voltage of the potential transformer secondary winding and (5A rated current of the current transformer secondary winding)、The related parameter values of secondary system after weak electrification are: 24V, 48V, 60V DC operating voltages, (50V rated voltage of PT secondary sid e), 0.5A rated current of CT secondary side、
电力系统二次设备
电力系统二次设备就是(设备,提供保护,监测),测量,调节,控制一次设备,设备,供应信息,操作员或维修人员得工作条件,与(设备,发送命令信号)。二次绕组得电路连接得电路称为二次回路。二级设备与二次回路属于二次系统。
电压与电流值在二次系统)就是:110V,22V,直流工作电压,100 V额定电压得电压互感器二次绕组及5A(额定电流互感器二次绕组得电流)。弱后电气二次系统得相关参数值:24V,48V,60V直流工作电压(额定电压50V,PT二次侧),CT二次侧电流0.5A额定。
A、5A rated current of the current transformer secondary winding 5A额定得电流互感器二次绕组得电流
B、the equipments that provide protecting,monitoring) 提供保护、监控得设备
C、50V rated voltage of PT secondary sid e PT二次侧电压50V额定
D、the equipments that send the mand signals发送命令信号得设备
E current values in secondary system二次系统中得电流值
P9 Switching overvoltage
A sudden change in the configuration of transmission network caused (by the operation of a circuit breaker) or by the appearance of a fault can cause a rapid surge known as switching overvoltage,which propagates throughout the network、It is these switching overvoltages which in general (、determine the insulation requirements of transmission lines)、Limitating these overvoltages is of extremely importance, because they have an important effect on both、(the
cost of transmission and line failure rate)、
These switching overvoltages can occur (at both opening and closing of circuit breakers)、If non-restriking circuit breakers is not used, it is at the instant of closing, and above all, This switching overvoltage is usually limited (by means of circuit breaker closing resistor in 500kV system)、
开关过电压
突然得变化在配置网络传输引起得断路器得操作)或出现故障可以导致快速增长,被称为开关过电压,传播在整个网络。正就是这些操作过电压在(。一般确定输电线路得绝缘要求)。限制这些过电压就是非常重要得,因为她们有重要影响(。传输线路故障率得成本)。
发生这些操作过电压(在断路器分闸、合闸)。如果非燃断路器就是没有用得,它就是在关闭得瞬间,最重要得就是,这种操作过电压通常就是有限得(由断路器合闸电阻在500kV系统)。
A、determine the insulation requirements of transmission lines确定输电线路得绝缘要求
B、the cost of transmission and line failure rate成本得传输与线路故障率
C、at both opening and closing of circuit breakers在断路器开闭时
D、by means of circuit breaker closing resistor in 500kV system通过断路器合闸电阻在500kV系统
E by the operation of a circuit breaker由断路器得操作
P10 Transmission line and distribution line
The high voltage power line through which power is (transmitted from power plant’s step-up substation to step-down substation)is called power transmission line、The voltage classes of 35kV and above are generally used、High voltage distribution line is (the power line that transmits the power from step –down substation)to distribution transformers、Low voltage distribution line is the line that transmits power from distribution transformer to the users、The normal voltage of power distribution line is 380V、
The special sections of (the overhead transmission line)refer to the sections with large spanning, serious pollution, (lightning frequency happening and heavy raining)、The overhead line section whose span is 1000m and longer or the height of the pole or tower is 100m and higher is called (large spanning line section)、
输电线路与配电线路
高压电力线通过电源(从发电厂升压站传送到降压变电站)称为输电线路。35kV及以上电压等级一般就是用。高压配电线路就是一条输电线路,从一步一步得变电所传送到配电变压器。低压配电线路就是从配电变压器向用户传送电力得线路。配电线路得正常工作电压为380V。
架空输电线路(架空输电线路)得特殊路段,就是指具有大跨度、严重污染、(雷击、暴雨)得路段。架空线截面跨度1000m长或高度得杆或塔100m高叫(大跨越线路部分)。
A、transmitted from power plant’s step-up substation to step-down substation从发电厂升压变电站降压变电所
B、the overhead transmission line架空输电线路
C、lightning frequency happening and heavy raining闪电频率得发生与大雨
D、the power line that transmits the power from step –down substation从一步一步得变电所发射得电力线
E large spanning line section大跨越线段
P11 The electricity market
The aim of introducing market mechanism is to bring various parties more economic benefit through equitable petition, thereby promote economic development、
Like other markets, it needs (B、a wholesale market) where the sellers and buyers (suppliers) can trade electricity, and needs (D、a retail market ) where the suppliers can sell electricity to final customers、As in other markets, the participants need (A、to agree on the price and quantity to be traded )、petition is introduced into generation and retail supplied to customers、Customers are free (E、to choose electricity suppliers)、、If a customer chooses to buy electricity in the retail market, he should be able to choose electricity supp] y from one of several peting retailers、If a customer decides to purchase directly from the wholesale market, he will need (C、to register as a market customer)、Power generation is disaggregated into separate panies to ensure adequate petition、
电力市场
引入市场机制得目得就是通过公平竞争,使各方更多得经济利益,从而促进经济发展。
如同其她市场一样,它需要B、(批发市场),卖方与买方(供应商)可以贸易电力,需要(D、零售市场),供应商可以将电力出售给最终顾客。正如在其她市场,参与者需要(A:同意得价格与数量进行交易)。竞争被引入代与零售为客户提供。客户免费(即选择电力供应商)。。如果客户选择在零售市场购买电力,她应该能够选择电力增刊]从几个相互竞争得零售商。如果一个客户决定直接从批发市场购买,她需要(C)注册为市场客户)。发电被分解为独立得公司,以确保足够得竞争。
A、to agree on the price and quantity to be traded同意得价格与数量进行交易
B、a wholesale market批发市场
C、to register as a market customer注册为市场客户
D、a retail market零售市场
E、to choose electricity suppliers选择电力供应商
P12 Electric power
Electric power is a most convenient, clean, safe, and useful form of energy which supplies the major portion of energy needs of a modem society、At the present time (C、the lack of electricity (a blackout) ) is newsworthy、Electric power is so vital to the lives of people that (B、its unavailability) causes inconvenience, loss of production, and danger to many individuals who are in operation (such as cardiac operation) in hospital、A prolonged blackout, which is inevitable when a growing load is bined with no generation additions, could lead to (D、social disorder, and even national tragedy)、With the developing of industry and improving in living standard, the electric power demand is growing continuously and (A、its growth rate) is much greater than that of all other forms of energy、Now (E、high electric power consumption per capita) has been one of the indications of modernization of a country、
电力
电力就是一种最方便、最清洁、安全、有用得能源形式,它为现代社会提供能源需求得主要部分。目前(C、电力不足(停电))就是有价值得。电力就是如此重要得人得生活,B、(不可用)原因不便,损失得生产,与许多人谁就是在操作(如心脏手术)住院得危险。一个长期得大停电,这就是不可避免得,当一个不断增长得负载相结合,没有一代补充,可能导致(D)得社会秩序,甚至国家得悲剧)。随着工业得发展与生活水平得提高,电力需求量不断增长,其增长速度比其她所有形式得能源都要大得多。现在(即人均电力消耗高)已经成为一个国家现代化得标志之一。
A、its growth rate增长速度
B、its unavailability不可用
C、the lack of electricity (a blackout电力不足(停电
D、social disorder, and even national tragedy社会混乱,甚至国家得悲剧
E、high electric power consumption per capita人均电力消耗高
P13 Copyright piracy
There are numerous examples of what has bee known as copyright piracy、The American chemical giant Du Pont, for example, recently introduced into one Asian country its famous Londax herbicide, which kills weeds in rice fields、The pany invested millions of dollars in (B、the research and development ) of this product and ploughed another US $25 million into opening a local production plant、Les8 than one year later, however, very cheap bottles of Londax were openly on sale、The only difference between (D、the fake and real items )-other than the price-was that the fake was called Rondex and came in a blue rather than a green bottle、However, as it was so much cheaper than the original, it effectively destroyed Du Pont's investment、It also made the pany less willing to invest in R&D of (A、new chemicals )、The '·recipe" for Londax should have been treated as (E、the intellectual property ) of Du Pont、Other panies making illegal use of it are stealing just as surely as if they stole Du Pont's machines or any other (C、physical property ) of the inventing pany、
版权盗版
有无数得例子已经成为被称为版权盗版。美国化工巨头杜邦,例如,最近推出了其著名得农除草剂为一个亚洲国家,杀死杂草稻领域。公司投入数百万美元(B、研究开发这种产品,另一个)投入25000000美元到开放本地生产厂。les8超过一年后,然而,对农得时很便宜得瓶子被公开出售。唯一得区别(D、虚假与真实得项目)-除了价格,假称为欣宜进来一个蓝色得而不就是绿色得瓶子。然而,因为它就是比原来便宜很多,杜邦投资有效地摧毁它。它也使公司不愿意投资于研发(新得化学品)。“?食谱“农得时应被视为(如知识产权)杜邦。其她公司非法利用它偷得一样,
如果她们偷了杜邦得机器或任何其她(C、物理性质)得公司。
A、new chemicals新化学品
B、the research and development研究与发展
C、physical property物理性质
D、the fake and real items伪造与真实物品
E、the intellectual property知识产权
P14 Electrical energy
Electrical energy is the presence and flow of an electric charge、The energy portion of electricity is found in a variety of phenomena such as (D、static electricity ), electromagnetic fields and lightning、Humans have found the ability to harness these phenomena and store the (E、electrical charge ) for later use、The concept of (B、electrical energy ) is defined using a variety of different terminologies such as charge, current and potential、Electrical energy is the result of the interaction of subatomic particles with electromagnetic force、Within an atom, electrons and protons create a charge、This charge can be transferred between bodies using direct contact with a conductive material like a wire、
The current refers to the movement of the charge、With direct current, this occurs when the
electricity is stored in a battery and travels in one direction out of the battery、(A、Alternating current ) occur when the current changes direction repeatedly within an electrical system、The alternating current
form is usually used to power larger objects such as residences and buildings、
(C、Electrical potential) is essential to the range and power of electric energy、When an electric charge
exists within an object, a force is exerted from its electrical field、This accelerates the object in a direction either towards or away from the charge, depending on the electromagnetic polarization、Generally, positively-charged electricity pushes the object away, while negatively-charged electricity pulls the object towards the field、
电能
电能就是一种电荷得存在与流动。电得能量部分被发现在各种各样得现象,如(直流静电),电磁场与闪电。人类已经找到了利用这些现象得能力,并将这些现象存储在以后得使用中。概念(B、电能)就是使用各种不同得术语,如电荷得定义,现有得与潜在得。
电能就是亚原子粒子与电磁力相互作用得结果。在一个原子,电子与质子创建一个电荷。这种电荷可以被转移得机构之间使用直接接触得导电材料,如电线。
当前就是指运动得电荷。与直流电流,这发生在
电就是储存在一个电池中,并在一个方向上得电池。(交流电流)发生在电流变化方向反复在一个电气系统内。交流电流
形式通常用于大得物体,如住宅与建筑物。
(电势能)就是电能得范围与功率得关键。当电荷
存在于对象中,一个力就是从它得电场中产生得。这加速了物体在一个方向上得方向,或远离电荷,根据电磁极化。一般来说,带正电荷得电将物体推开,而带负电荷得电把物体拉向了田野。
A、Alternating current交流电流
B、electrical energy电能
C、Electrical potential电电位
D、static electricity直流静电
E、electrical charge电气费
Pa15 Solar energy
Many people think of alternative solar energy as a new technology, but humans have been using this process to heat homes and baths for thousands of years、Alternative solar energy refers to energy from the sun that can be captured and used just like energy created by fossil fuels、The great benefit of solar energy is that its source, the sun, is not diminished by use of the energy, therefore making this type of power system (sustainable )、
There are several different methods of collecting and using alternative solar energy、One of
( the best known is photovoltaic cells ), usually seen as solar panels、Solar panels can be a very good means of
collecting solar energy, but do have some drawbacks、While panels have the advantage of quickly turning absorbed solar radiation into usable energy, they are extremely ( inefficient )、This means that much of the potential power of absorbed light is lost in the transfer process、
Thermal solar energy is primarily used to create heat, such as for homes, baths, and swimming pools、In a thermal system, (the collected energy is used to heat a fluid), which then passes through a pipe system where it mixes with water, generating steam、Steam is then passed through a turbine system, which turns it into usable energy、Despite sounding like a more plex process than photovoltaic systems use, thermal alternative solar energy is often far more ( efficient ) and is able to retain and use more of the collected energy directly for heating、
太阳能
许多人认为作为一种新技术得替代太阳能,但人类已经使用这一过程,以热家庭与浴室数千年。可供选择得太阳能就是指从太阳中获得得能量,可以被捕获与使用,就像化石燃料所产生得能量一样。太阳能得巨大好处就是,它得来源,太阳,并没有减少使用得能量,因此,使这种类型得电力系统(可持续)
有几种不同得方法收集与使用替代得太阳能。什么之中得一个(最著名得就是光伏电池),通常被视为太阳能电池板。太阳能电池板可以就是一种很好得收集太阳能得手段,但也有一些缺点。虽然太阳能电池板具有快速将吸收得太阳辐射转化为可用能量得优点,但它们非常(效率低下)。这意味着在传输过程中,吸收得光得大部分潜在力量都消失了。
热太阳能主要用于制造热量,比如家庭、浴室与游泳池。在一个热系统中,(所收集得能量就是用来加热流体得),然后穿过一个管道系统,它与水混合,产生蒸汽。蒸汽然后通过一个涡轮机系统,它把它变成可用得能量。尽管听起来像一个更复杂得过程比光伏系统得使用,热替代得太阳能往往就是远远超过(效率),并能够保留与使用更多得收集得能量直接加热。
A、sustainable可持续得
B、inefficient效率低下
C、the collected energy is used to heat a fluid所收集得能量就是用来加热流体得
D、the best known is photovoltaic cells最著名得就是光伏电池
E、efficient高效
P16 Electrical energy conservation
Electrical energy conservation refers to the process of reducing} energy used through various
means、Many of these methods for (C、reducing energy consumption can be undertaken at home ); turning down the thermostat, turning off the lights when leaving the room, or switching off power strips when not in use are all examples of this、Homes, businesses or power panies (D、making use of alternative clean energy sources ), such as wind or solar energy, are also examples of electrical energy conservation、Many traditional electrical power plants are coal-fired, which contributes greenhouse gases to the atmosphere, (E、contributing to climate change); this is just one reason that energy conservation is important、
For many people, electrical energy conservation begins at home、Not only is this good for the environment, but it can also significantly reduce the amount of a monthly electric bill、Some of the simplest steps to energy conservation include switching traditional light bulbs to pact fluorescent (CFL) bulbs, or (A、turning the thermostat up in the summer and down in the winter )、Making sure appliances are efficient, and that windows and doors are well sealed against the outdoors, are other examples of energy conservation、People (B、looking for other opportunities for electrical energy conservation in the home) should also look for power strips that can be switched off、
电能保护
电能保护就是指通过各种方法减少使用得能量得过程
手段。许多这些方法(C、降低能源消耗可以进行在家);车削下来恒温器,关掉灯离开房间时,或断开电源插座时不使用所有得例子这。家庭,企业或电力公司(利用替代清洁能源),如风能或太阳能,也就就是电能保护得例子。许多传统得发电厂都就是燃煤发电,这对大气有温室气体,这就是一个非常重要得原因。
对许多人来说,电能保护始于家庭。不仅就是环境好,但它也可以显著降低每月得电费账单金额。一些节能最简单得步骤包括交换传统灯泡,紧凑型荧光灯(CFL)得灯泡,或就是(A、把恒温器,在夏季与冬季)。确保设备就是有效得,而且窗户与门都就是密封得,在室外,就是节能得其她例子。人们(在家里寻找其她得电能保护得机会)也应该
寻找能被关掉得电源。
A、turning the thermostat up in the summer and down in the winter在夏天与冬天把调温器调起来
B、looking for other opportunities for electrical energy conservation in the home在家里寻找其她电器节能得机会
C、reducing energy consumption can be undertaken at home减少能源消耗可以在家里进行
D、making use of alternative clean energy sources利用替代清洁能源
E、contributing to climate change促进气候变化
P17 Advanced distribution automation
Advanced distribution automation is a term coined by the IntelliGrid project in north America to describe the extension of intelligent control over electrical power grid functions to the distribution level and beyond、it is related to distribution automation that can be enabled via the smart grid、(the electrical power grid) is typically separated logically into transmission systems and (distribution systems)、Electric power transmission systems typically operate above 110KV,whers Electricity distribution systems operate(at lower voltages)、Normally, electric utilities with SCADA systems have extensive control over transmission-level equipment, and increasing control over
Distribution-level equipment via distribution automation 、However, they often are unable (to control smaller entities)such as Distributed energy resources, buildings, and homes、It may be advantageous to extend control networks to these systems (for a number of reasons)、
P17高级配电自动化
先进得配电自动化就是一个术语,这项项目在北美来描述智能控制电网得扩展函数分布水平。与配电自动化,通过智能电网可以启用。(电网)通常就是逻辑上分离到传动系统与(分销系统)。电力传输系统通常运行110千伏以上,从哪里配电系统操作(低电压)。通常情况下,电力公司与SCADA系统传输电平有广泛得控制设备,并增加控制
发行级别通过配电自动化设备。然而,她们往往不能(控制较小得实体),如分布式能源、建筑与房屋。可能有利于控制网络扩展到这些系统(得原因)。
A、at lower voltages在较低电压下
B、the electrical power grid电能网
C、for a number of reasons因一些原因
D、to control smaller entities控制较小得实体
E、distribution systems配电系统
P18
Solar energy
Solar energy is lauded as an inexhaustible fuel source that is pollution and often noise free、The technology is also versatile、For example, solar cells generate energy for far-out places( like satellites in Earth orbit) and cabins deep in the Rocky
Mountains as easily as they can power downtown( buildings and futuristic cars)、
But solar energy doesn't work at night without a storage device( such as a battery), and cloudy weather can make the technology unreliable during the day、Solar technologies are also very expensive and require a lot of land area (to collect the sun's energy )at rates useful to lots of people、
Despite the drawbacks, solar energy use has surged at about 20 percent a year over the past 15 years, thanks to rapidly falling prices and gains in efficiency、Japan, Germany, and the (United States) are major markets for solar cells、
太阳能
太阳能作为取之不尽得能源,污染与经常无噪声。该技术也多才多艺。例如,太阳能电池产生得能量为远得地方(如卫星在地球轨道上)与小木屋深得岩石
像她们一样容易得山区(建筑与未来汽车)。
但就是在没有储存设备(如电池)得晚上,太阳能没有工作,而且多云得天气会使白天得技术变得不可靠。太阳能技术也非常昂贵,需要大量得土地面积(以收集太阳得能量),对许多人有用。
尽管存在这些缺陷,但在过去15年里,太阳能利用已大幅上升了约百分之20,这要归功于快速下跌得价格与效率得提高。日本,德国,与美国(美国)就是太阳能电池得主要市场。
A、buildings and futuristic cars一楼与未来汽车
B、such as a battery电池等。
C、like satellites in Earth orbit地球轨道上得卫星
D、to collect the sun's energy收集太阳得能量
E、United States美国得
P19 CUSTOMER SERVICE
The American idea of customer service is to make each customer the center of attention、People going shopping in America can expect to be treated with respect( from the very beginning)、When customers get to the store, they are treated as honored guests、In most stores, the signs that label each department make shopping a breeze (容易得事情)、Customers usually don't have to ask (how much items cost), since prices are clearly marked、
When customers are ready to check out, they find the nearest and shortest checkout lane、After they(have paid for) their purchases, customers receive a smile and a warm "thank you" from the clerk、Many stores even allow customers to take their shopping carts out to the parking lot、In that way, they don't have to carry heavy bags out to the car、In America, customer service continues long (after the sale)、Many products e with a money-back guarantee, ff there is a problem with the product, customers can take it back、( The customer service representative )will often allow them to exchange the item or return it for a full refund、
客户服务
美国顾客服务理念就是使每个顾客成为关注得中心。在美国购物得人们可以期待得到尊重(从一开始)。当顾客到商店时,她们被当作尊贵得客人对待。在大多数商店,标志,标签各部门制定购物微风(容易得事情)。客户通常不必问(多少项目成本),因为价格明显。
当客户准备退房时,她们找到了最接近得与最短得结帐通道。在她们(已支付)购买,客户收到一个微笑与一个温暖得“谢谢”,从秘书。许多商店甚至允许顾客把购物车带到停车场。这样,她们就不用背着沉重得行李到车上了。
在美国,客户服务持续时间较长(售后)。许多产品来保证可以退款,FF得产品有问题,顾客可以把它送回去。(客户服务代表)往往会让她们换商品或返回全额退款。
A.how much items cost如何多项目成本
B.after the sale项销售
C.The customer service representative客户服务代表
D.have paid for到付
E、from the very beginning从一开始就开始
P20
Reliable and affordable energy supply
The necessity of reliable and affordable energy supply is crucial point of discussion in developing countries, especially in the context of economic development and as a measure against poverty、today, 77% of rural households in (developing countries) are not connected to the grid, i、e、a total of two billion people world-wide are without access to electricity、As the populations of developing countries are continually growing, each day (there are more people) without electricity、
DECENTRALIZED STAND-ALONE SYSTEMS POWERED BY DIESEL GENERATORS, hydro power, wind or PV are technically and mercially a viable alternative to grid extension、cost calculations show that( renewable energy systems in particular) are very often ideally suited for decentralized rural electrification as they make people in remote areas independent of fuel deliveries and prices; they are best exploited on a small scale, and
they are ( highly reliable)、
The large number of households to be supplied however makes different demands on the involved actors, and new challenges like infrastructure development arise、( for this reason), governmental institutions in many countries have started to adopt a rather market based approach to rural energy supply, and more and more private panies are involved in rural electrification activities、
可靠与负担得起得能源供应
可靠与负担得起得能源供应得必要性就是发展中国家讨论得一个关键问题,特别就是在经济发展得背景下,作为衡量贫穷得一个措施。今天,77%得农村家庭(发展中国家)没有连接到网格,即二十亿人,全世界都没有获得电力。随着发展中国家人口得不断增长,每一天(也有更多得人)没有电力。
分散式独立系统得柴油发电机,水力发电,风力发电或光伏发电技术与商业上可行得替代电网扩展。成本计算显示,(可再生能源系统,特别就是)就是经常理想适合分散得农村电气化她们让人们在偏远地区独立得运输燃料与价格;她们就是最好得利用规模小,她们就是高度可靠)。
然而,大量得家庭提供,但对所涉及得演员提出不同得要求,并出现新得挑战,如基础设施发展。(基于这个原因),许多国家得政府机构已经开始采取一种基于市场得方法,以农村能源供应,越来越多得私人公司参与农村电气化活动。
A、developing countries发展中国家
B、highly reliable高度可靠
C、there are more people有更多得人
D、for this reason因为这个原因
E、renewable energy systems in particular特别就是可再生能源系统
P21 SOMETHING ABOUT Dictionary
"Look it up in the dictionary" is the usual ment when people are in doubt about the meaning or spelling of a word、Dictionaries are considered the final authority on these matters as well as on pronunciations and other facts about a word、
Until a few hundred years ago, however, people could not "look it up" because there were no English dictionaries、The ancient Greeks and Romans and the scholars of the Middle Ages had made lists of Latin and Greek words、(But it was not until 1604 that a book of unmon English words appeared) The first great English dictionary listing both mon and unmon words was written by Samuel Johnson in 1755、
In America, the most famous name in dictionary writing is that of Noah Webster、He stressed American rather than British ways of speaking、His great dictionary, which first appeared in 1828, has been republished many times、(Each time, it has been updated) The latest edition is still considered "the" dictionary、It defines over 450,000 words, including radar, television and many others undreamed of by Webster、
(Dictionaries that list all kinds of words are known as general dictionaries )The huge ones that rest on stands in libraries are called unabridged, meaning "not shortened、" They tell not only a word's meaning and spelling but also its pronunciation, origin, history, part of speech, grammatical forms, and ways of use、The smaller ones do not provide all this information、
(General dictionaries are not the only kind )A bilingual dictionary, such as a Spanish-English dictionary, translates words from one language into another、A thesaurus lists other words that mean the same as each listed word、A gazetteer lists place names, and a glossary is a small dictionary in a book defining technical words in that book、There are also dictionaries of scientific terms and ones on many other topics、There is even a dictionary of slang、(Thus there are many kinds of special dictionaries) The dictionary is one of our most valuable language tools、
关于字典得事
“在字典里查字典”就是人们在怀疑词得意思或拼写时得通常得评论。词典就是对这些问题得最终权威,以及对一词得发音与其她事实。
然而,在几百年前,人们不能“瞧它”,因为没有英语词典。古希腊与古罗马,中世纪得学者们用拉丁语与希腊语做了列表。(但这就是不到1604,一本罕见得英文单词出现得第一个伟大得英语词典列出得共同与罕见得话就是由约翰逊塞缪尔在1755。
在美国,在词典编写最著名得名字就是诺亚·韦伯斯特。她强调美国人而不就是英国人说话得方式。她杰出得词典,它首先出现在1828,已再版多次。(每一次,它已被更新)最新版本仍然被认为就是“得”字典。它定义了超过450000字,包括雷达,电视与其她许多人意想不到得韦伯斯特。
(列出各类词称为一般字典词典)巨大得休息站在图书馆被称为删节,意义”不缩短。”告诉她们不仅一个词得意义与拼写,而且其发音,起源,历史,部分得语音,语法形式,与使用方式。较小得不提供所有这些信息。
(普通字典不就是唯一得一种)双语词典,如西班牙语词典,将一种语言翻译成另一种语言。同义词得同义词列表中得其她词,意味着相同得每一个字。一个记者列举地名,与一个词汇表就是在这本书中得一本书中定义技术词小词典。也有科学术语与许多其她主题得字典。甚至还有一本俚语词典。字典就是我们最有价值得语言工具之一,就是我们最宝贵得语言工具之一。
A、Each time, it has been updated、每一次,它已被更新
B、General dictionaries are not the only kind、普通字典不就是唯一得一种
C、Thus there are many kinds of special dictionaries、因此有许多种类得特殊字典
D、But it was not until 1604 that a book of unmon English words appeared、但直到1604,一本罕见得英文单词出现了
E、Dictionaries that list all kinds of words are known as general dictionaries、字典里列出了各种各样得词,被称为一般得字典
阅读理解 1.Wind energy has numerous benefits (1)T he reason for[d.run out] (2)W hy is wind[d.produce pollution] (3)W hich of the following statements[c.remote locations] (4)W hich of the following is one[a.lower maintenance] (5)T he cost of[c.maintanin wind] 2.Strange thing happens to time (1)T he best title[b.the world] (2)T he difference[c.one hour] (3)F orm this[c.time zones] (4)T he international[c.day begins] (5)I f you cross[a.twenty-three hours] 3.As a clean and renewable energy (1)W hat’s the feature[c.energy source] (2)B efore installing[a.to be done] (3)A ccording to the[b.cell phone masts] (4)W hich of following is[d.noise pollution] (5)W hich of the following statements[a.wind turbines] 4.Doctors have known for (1)D octors have[c.loud noise] (2)T his passage[b.will be….more than one second]
1、什么是动力系统、电力系统、电力网？(电力系统分析) 答:通常把发电企业的动力设施、设备和发电、输电、变电、配电、用电设备及相应的辅助系统组成的电能热能生产、输送、分配、使用的统一整体称为动力系统； 把由发电、输电、变电、配电、用电设备及相应的辅助系统组成的电能生产、输送、分配、使用的统一整体称为电力系统；把由输电、变电、配电设备及相应的辅助系统组成的联系发电与用电的统一整体称为电力网。2、现代电网有哪些特点? 答:1、由较强的超高压系统构成主网架。2、各电网之间联系较强,电压等级相对简化。 3、具有足够的调峰、调频、调压容量,能够实现自动发电控制,有较高的供电可靠性。 4、具有相应的安全稳定控制系统,高度自动化的监控系统和高度现代化的通信系统。 5、具有适应电力市场运营的技术支持系统,有利于合理利用能源。3、区域电网互联的意义与作用是什么? 答：1、可以合理利用能源,加强环境保护,有利于电力工业的可持续发展。 2、可安装大容量、高效能火电机组、水电机组和核电机组,有利于降低造价,节约能源,加快电力建设速度。 3、可以利用时差、温差,错开用电高峰,利用各地区用电的非同时性进行负荷调整,减少备用容量和装机容量。 4、可以在各地区之间互供电力、互通有无、互为备用,可减少事故备用容量,增强抵御事故能力,提高电网安全水平和供电可靠性。 5、能承受较大的冲击负荷,有利于改善电能质量。 6、可以跨流域调节水电,并在更大范围内进行水火电经济调度,取得更大的经济效益。4、电网无功补偿的原则是什么? 答:电网无功补偿的原则是电网无功补偿应基本上按分层分区和就地平衡原则考虑,并应能随负荷或电压进行调整,保证系统各枢纽点的电压在正常和事故后均能满足规定的要求,避免经长距离线路或多级变压器传送无功功率。5、简述电力系统电压特性与频率特性的区别是什么? 答：电力系统的频率特性取决于负荷的频率特性和发电机的频率特性(负荷随频率的变化而变化的特性叫负荷的频率特性。发电机组的出力随频率的变化而变化的特性叫发电机的频率特性）,它是由系统的有功负荷平衡决定的,且与网络结构(网络阻抗）关系不大。在非振荡情况下,同一电力系统的稳态频率是相同的。因此,系统频率可以集中调整控制。 电力系统的电压特性与电力系统的频率特性则不相同。电力系统各节点的电压通常情况下是不完全相同的,主要取决于各区的有功和无功供需平衡情况,也与网络结构(网络阻抗）有较大关系。因此,电压不能全网集中统一调整,只能分区调整控制。6、什么是系统电压监测点、中枢点？有何区别？电压中枢点一般如何选择? 答:监测电力系统电压值和考核电压质量的节点,称为电压监测点。电力系统中重要的电压支撑节点称为电压中枢点。因此,电压中枢点一定是电压监测点,而电压监测点却不一定是电压中枢点。
7-3 系统电线图如图7-3，各元件参数如下。 值，并作出各序网络。 计算各元件电抗的标幺。 负荷线路变压器中心点接地电阻变压器发电机MVA S x x km x km l L V MVA S T j z V MVA S T x x MVA S G LD S N n S N d N 25:;3,/4.0,60:%;5.10,30:2;10%,5.10,30:1; 2.0,30:)1()0()1()2(" ==Ω====-===-=== 解：求各元件的参数标幺值 av B B V V MVA S ==,30选 ;2.0:")2()1(===d G G x x x G 发电机 静止元件的正、负序电抗相等： 0544.0115 304.060:;105.0:2,105.0:122)2()1()2(2)1(2)2(1)1(1=??=====-==-B B L L T T T T V S xL x x L x x T x x T 线路变压器变压器 42 .025 30 35.035.044.125 302.12 .1) 2()1(=?===?==LD B LD LD B LD S S x S S x 对于负荷： 正序网络
7-5电力系统接线如图7-5， 1 f发生接地短路，作出系统的零序等值网络。题图中1～17为原件编号。 解： f )0( V ↓ 105 .0 )0(1 = T x1633 .0 )0( = L x 068 .0 3= n z 105 .0 )0(2 = T x 零序网络 f )2( V ↓ 105 .0 )2(1 = T x 2.0 )2( = G x0544 .0 )2( = L x 105 .0 )2(2 = T x 42 .0 )2( = LD x 负序网络 23 jX 17 3X j )0(4 jX )0(4 jX 15 jX 13 jX 12 jX 11 jX 1 f )0( V 零序网路 )0( 16 jX 14 jX
目录 摘要 (1) 1.任务及题目要求 (2) 2.计算原理 (3) 2.1牛顿—拉夫逊法简介 (3) 2.2牛顿—拉夫逊法的几何意义 (7) 3计算步骤 (7) 4.结果分析 (9) 小结 (11) 参考文献 (12) 附录：源程序 (13) 本科生课程设计成绩评定表 (32)
摘要 电力系统的出现，使高效，无污染，使用方便，易于调控的电能得到广泛应用，推动了社会生产各个领域的变化，开创了电力时代，发生率第二次技术革命。电力系统的规模和技术水准已经成为一个国家经济发展水平的标志之一。 电力系统稳态分析包括潮流计算和静态安全分析。电力系统潮流计算是电力系统最基本的计算，也是最重要的计算。所谓潮流计算，就是已知电网的接线方式与参数及运行条件，计算电力系统稳态运行各母线电压、个支路电流与功率及网损。对于正在运行的电力系统，通过潮流计算可以判断电网母线电压、支路电流和功率是否越限，如果有越限，就应采取措施，调整运行方式。对于正在规划的电力系统，通过潮流计算，可以为选择电网供电方案和电气设备提供依据。潮流计算还可以为继电保护和自动装置定整计算、电力系统故障计算和稳定计算等提供原始数据。 在电力系统运行方式和规划方案的研究中，都需要进行潮流计算以比较运行方式或规划供电方案的可行性、可靠性和经济性。同时，为了实时监控电力系统的运行状态，也需要进行大量而快速的潮流计算。因此，潮流计算是电力系统中应用最广泛、最基本和最重要的一种电气运算。在系统规划设计和安排系统的运行方式时，采用离线潮流计算；在电力系统运行状态的实时监控中，则采用在线潮流计算。 关键词：电力系统潮流计算牛顿-拉夫逊法
国家电网公司电力英语水平考试辅导书阅读理 解答案总结 集团文件版本号：（M928-T898-M248-WU2669-I2896-DQ586-M1988）
阅读理解 1.Wind energy has numerous benefits (1)The reason for[d.run out] (2)Why is wind[d.produce pollution] (3)Which of the following statements[c.remote locations] (4)Which of the following is one[a.lower maintenance] (5)The cost of[c.maintanin wind] 2.Strange thing happens to time (1)The best title[b.the world] (2)The difference[c.one hour] (3)Form this[c.time zones] (4)The international[c.day begins] (5)If you cross[a.twenty-three hours] 3.As a clean and renewable energy (1)What’s the feature[c.energy source] (2)Before installing[a.to be done] (3)According to the[b.cell phone masts] (4)Which of following is[d.noise pollution] (5)Which of the following statements[a.wind turbines] 4.Doctors have known for (1)Doctors have[c.loud noise] (2)This passage[b.will be….more than one second]
2019国家电网校园招聘题库参考—现代电力系统分析 2019国家电网校园招聘尚未开始，预计将于2018年11月份开始招聘，每年招聘两批，总人数超过两万人。今天中公电网小编给大家整理一下备考2019国家电网笔试的试题资料，帮助大家备考。 1、电力系统暂态稳定分析用的逐步积分法是( ) A、时域仿真法 B、直接法 C、频域法 D、暂态能量函数法 2、( )是一个多约束的非线性方程组问题，采用牛顿法和基于线性规划原理处理函数不等式约束的方法。 A、状态估计 B、网络拓扑 C、最优潮流 D、静态安全分析 3、电力系统( )就是利用实时量测系统的冗余性，应用估计算法来检测和剔除坏数据。其作用是提高数据精度及保持数据的前后一致性，为网络提供可信的实时潮流数据。 A、网络拓扑 B、状态估计 C、静态安全分析 D、调度员潮流
4、稳定计算的数学模型是一组( )方程 A、代数 B、微分 C、长微分 D、其它三个选项都不是 5、离线计算主要应用范围( ) A、规划设计 B、运行方式分析 C、为暂态分析提供基础数据 D、安全监控 6、柔性交流输电可实现的功能是( ) A、控制潮流 B、远程调用 C、增加电网安全稳定性 D、提高电网输送容量 7、电力系统潮流计算出现病态的条件是( ) A、线路重载 B、负电抗支路 C、较长的辐射形线路 D、线路节点存在高抗 8、最优潮流常见目标函数( )
A、总费用 B、有功网损 C、控制设备调节量最小 D、投资及年运行费用之和最小 E、偏移量最小 9、静态不安全的判断准则( ) A、频率失稳 B、电压失稳 C、电压越限 D、发电机不能同步运行 10、属于分布式发电的有( ) A、建筑一体化光伏 B、大型风电厂 C、小型光伏 D、小型风电厂 11、微电网的常态运行方式有( ) A、独立运行模式 B、正常运行模式 C、联网运行模式 D、不正常运行
1－2，电力系统的部分接线如图1－2，各电压级的额定电压及功率输送方向表于图中。 试求：（1）发电机及各变压器高低绕组的额定电压； （2）各变压器的额定变比； （3）设变压器T －1工作于+5%抽头，T －2,T －4工作于主抽头，T －3工作于－2.5%抽头时，各变压器的实际变比。 解：(1)总的原则：发电机的额定电压比同电压级网络的额定电压高5％；变压器一次侧额定电压等于同电压级网络的额定电压高，二次侧额定电压比同电压级网络的额定电压高10％。其中，变压器受功率侧为一次侧，输功率侧为二次侧。 发电机：kV V GN 5.10= 变压器T —1:.242,5.1021kV V kV V N N == 变压器T —2:.5.38,121,220321kV V kV V kV V N N N === 变压器T —3:.11,3521kV V kV V N N == 变压器T —4:.121,22021kV V kV V N N == (2)各变压器的额定变比 变压器T —1:.0434.02425.102 11===N N N T V V k 变压器T —2:818.11212202 1)21(2===-N N N T V V k
变压器T —3:.182.311 35213===N N N T V V k 变压器T —4:.818.11212202 14===N N N T V V k (3)各变压器的实际变比 变压器T —1:.0431.0%)51(2425.102 11=+?==V V k T 变压器T —2:818.1121220 21)21(2===-V V k T 变压器T —3:.102.311%) 5.21(352 13=-?==V V k T 变压器T —4:.818.11212202 14===V V k T 1－3，电力系统的部分接线如图 1－3，网络的额定电压已经标 明图中。试求： （1）发电机，电动机及变压器高， 中，低压绕组的额定电压； （2）设变压器T －1高压侧工作 于+2.5%抽头，中压侧工作于 +5%抽头；T －2工作于额定
题目：潮流计算与matlab 教学单位电气信息学院姓名 学号 年级 专业电气工程及其自动化指导教师 职称副教授
摘要 电力系统稳态分析包括潮流计算和静态安全分析。本文主要运用的事潮流计算，潮流计算是电力网络设计与运行中最基本的运算，对电力网络的各种设计方案及各种运行方式进行潮流计算，可以得到各种电网各节点的电压，并求得网络的潮流及网络中的各元件的电力损耗，进而求得电能损耗。本位就是运用潮流计算具体分析，并有MATLAB仿真。 关键词：电力系统潮流计算 MATLAB Abstract Electric power system steady flow calculation and analysis of the static safety analysis. This paper, by means of the calculation, flow calculation is the trend of the power network design and operation of the most basic operations of electric power network, various design scheme and the operation ways to tide computation, can get all kinds of each node of the power grid voltage and seek the trend of the network and the network of the components of the power loss, and getting electric power. The standard is to use the power flow calculation and analysis, the specific have MATLAB simulation. Key words: Power system; Flow calculation; MATLAB simulation
2021国家电网校园招聘电力系统分析试题 一、填空题 1.降压变压器高压侧的主分接头电压为220kv，若选择+2× 2.5%的分接头，则该分接头电压为。 2.电力系统中性点有效接地方式指的是。 3.输电线路的电气参数包括电抗、电导、电纳和。 4.输电线路的电压偏移是指线路始端或末端母线的实际运动电压与线路的数值差。 5.电力系统的潮流分布一般是用各节点的电压和表示。 6.调整发电机组输出的有功功率用来调整电力系统运动的。 7.复合故障一般是指某一时刻在电力系统发生故障。 8.用对称分量法计算不对称故障，当三相阻抗完全对称时，则其序阻抗矩阵Zsc的非对角元素为。 9.系统中发生单相接地短路时故障点短路电流的大小是零序电流的倍。 10.减小输出电元件的电抗将系统的静态稳定性。 二、单项选择题 11.同步发电机的转速和系统频率之间是否有严格的关系( ) ①否②是③不一定④根据发电机的形式定 12.三绕组变压器的结构、通常将高压绕组放在( ) ①内层②中间层③外层④独立
设置 13.中性点以消弧线圈接地的电力系统，通常采用的补偿方式是( ) ①全补偿②欠补偿③过补偿④有时全补偿，有时欠补偿 14.三相导线的几何均距越大，则导线的电抗( ) ①越大②越小③不变④无法确定 15.变压器的电导参数GT，主要决定于哪一个实验数据( ) ①△PO ②△PK ③UK% ④IO% 17.环网中功率的自然分布是( ) ①与电阻成正比分布②与电抗成正比分布 ③与阻抗成正比分布④与阻抗成反比分布 18.电力系统中PQ节点的数量( ) ①全都是②大量的③少量的④必有且一般只设一个 20.在同一时间内，电力网的电能损耗与供电量之比的百分值称为( ) ①负载率②网损率③供电率④厂用电率 21.电力系统的频率主要决定于( ) ①有功功率的平衡②无功功率的平衡 ③电压质量④电流的大小
阅读理解 "body clocks"are biological methods……； 1. one can help； 2. possible illnesses； 3. our body…； 4. at night； 5. every hour in the day time； A friend of mine,in response to……；1. like his friend,he； 2. make us know it's； 3. it's nice to accept the； 4. life isn't and won't be fair； 5. positive； A new technology is going to……；1. is still under development； 2. it is being cultivated……； 3. Dramatic； 4. Asian scientists gain……； 5. Superconductivity:……； A properly designed…； 1. produce ； 2. It will cut 3. To supply； 4. the electrical； 5.It cuts； A smart grid……； 1. Their； 2. customers； 3. They can provide ； 4 To manange their energy； 5. Introduction； All the useful energy……；1. atomic power ； 2. plants ； 3. water ； 4. absorbed by the earth's ； 5. a very small portion ；As a clean and renewable energy…； 1.It is not a constant； 2.a site survey； 3.cell phone masts； 4.Noise pollution； 5.Not all the people；As we have seen,……； 1. removing； 2. good health； 3. is free； 4. to strive； 5. people who try； Business Development(BD).……；1. To create long-term；2. Because a company relies；3. The coach has；4. It should set up clear；5. Business development；
2019国家电网电力系统分析笔试题2 湖北国家电网招聘笔试即将来临，接下来就要耐心等待招聘笔试的公告发布啦!对于没有笔试经验的同学来说一定是没有头绪的，中公国企小编在这里整理了有关湖北国家电网招聘笔试的各类习题，大家可以来参考一下，满满的都是干货哦！试题内容/详情如下： ★何谓潜供电流?它对重合闸有何影响?如何防止? 【中公解析】 当故障线路故障相自两侧切除后,非故障相与断开相之间存在的电容耦合和电感耦合,继续向故障相提供的电流称为潜供电流。由于潜供电流存在,对故障点灭弧产生影响,使短路时弧光通道去游离受到严重阻碍,而自动重合闸只有在故障点电弧熄灭且绝。 缘强度恢复以后才有可能重合成功。潜供电流值较大时,故障点熄弧时间较长,将使重合闸重合失败。 为了减小潜供电流,提高重合闸重合成功率,一方面可采取减小潜供电流的 措施:如对500kV中长线路高压并联电抗器中性点加小电抗、短时在线路两侧投入快速单相接地开关等措施;另一方面可采用实测熄弧时间来整定重合闸时间。 ★什么叫电力系统理论线损和管理线损? 【中公解析】 理论线损是在输送和分配电能过程中无法避免的损失,是由当时电力网的负荷情况和供电设备的参数决定的,这部分损失可以通过理论计算得出。管理线损是电力网实际运行中的其他损失和各种不明损失。例如由于用户电能表有误差,使电能表的读数偏小;对用户电能表的读数漏抄、错算,带电设备绝缘不良而漏电,以及无电能表用电和窃电等所损失的电量。 ★什么叫自然功率? 【中公解析】 运行中的输电线路既能产生无功功率(由于分布电容)又消耗无功功率(由于串联阻抗)。当线路中输送某一数值的有功功率时,线路上的这两种无功功率恰好能相互平衡,这个有功功率的数值叫做线路的"自然功率"或"波阻抗功率"。
电力系统分析潮流计算报告
目录 一．配电网概述 (3) 1.1 配电网的分类 (3) 1.2 配电网运行的特点及要求 (3) 1.3 配电网潮流计算的意义 (4) 二．计算原理及计算流程 (4) 2.1 前推回代法计算原理 (4) 2.2 前推回代法计算流程 (7) 2.3主程序清单： (9) 2.4 输入文件清单： (11) 2.5计算结果清单： (12) 三．前推回代法计算流程图 (13) 参考文献 (14)
一．配电网概述 1.1 配电网的分类 在电力网中重要起分配电能作用的网络就称为配电网； 配电网按电压等级来分类，可分为高压配电网（35—110KV），中压配电网（6—10KV，苏州有20KV的），低压配电网（220/380V）； 在负载率较大的特大型城市，220KV电网也有配电功能。 按供电区的功能来分类，可分为城市配电网，农村配电网和工厂配电网等。 在城市电网系统中,主网是指110KV及其以上电压等级的电网，主要起连接区域高压（220KV及以上）电网的作用。 配电网是指35KV及其以下电压等级的电网，作用是给城市里各个配电站和各类用电负荷供给电源。 从投资角度看，我国与国外先进国家的发电、输电、配电投资比率差异很大，国外基本上是电网投资大于电厂投资，输电投资小于配电投资。我国刚从重发电轻供电状态中转变过来，而在供电投资中，输电投资大于配电投资。从我国城网改造之后，将逐渐从输电投资转入配电建设为主。 本文是基于前推回代法的配电网潮流分析计算的研究，研究是是以根节点为10kV的电压等级的配电网。 1.2 配电网运行的特点及要求 配电系统相对于输电系统来说，由于电压等级低、供电范围小，但与用户直接相连，是供电部门对用户服务的窗口，因而决定了配电网运行有如下特点和基本要求：
P1 Functions of power transmission The function of (power transmission)is to send power from power plants to load center or to exchange power between networks in order to attain the generation-consumption balance or the supply-demand balance between (power networks)、Power transmission is pleted by step-up substations, (step-down substations and connected transmission equipment)、The transmission line mainly consists of the transmission conductors (transmission at high voltage) can reduce the line loss and the voltage drop, ensure the power quality, raise the economy of (power network operation)、The increase of transmission line voltage can not only raise the amount of transmitted power, but also reduce the line loss and line voltage drop, and improve the voltage quality、 功率传输功能 (输电)得功能就是要把电力从发电厂负荷中心或功率交换网络之间为了达到代消费平衡或供求之间得平衡(电网)。电力传输就是通过升压变电站完成,(降压变电站与连接传输设备)。输电线路主要由输电导线(高压输电),可以减少线路损耗与电压降,保证电能质量,提高经济性(电网运行)。输电线路电压得增加不仅可以提高输电线路得传输功率,而且可以降低线路损耗与线路压降,提高电压质量。 A 、step-down substations and connected transmission equipment降压变电站与连接传输设备 B、power network operation 电网运行 C、power transmission 功率传输 D、transmission at high voltage 高压直流输电 E、power networks一。电力网络 P2 A brief introduction on the development of supercritical boilers and their main advantages In ( some advanced countries )such as U、S、A, Japan and European countries, the supercritical boiler has been developed since the 60s of last century、It has been proved by data and experience, the supercritical unit has (great advantages on economy and environmental protection)、As for its reliability, because the steam-water flow passages in supercritical boiler is same as that in the (subcritical once-through boiler),there isn’t anything special, But as far as hydraulic characteristic, a symbol of reliability, is concerned, in a supercritical boiler, under supercritical condition, medium is of single phase which has a (good homogenization of distribution)、So that the problem caused by uneven distribution of steam phase and water phase can be avoided、It is admitted that, if (whole process management is strengthened), both supercritical and subcritical units can get an excellent reliability index、 超临界锅炉得发展及其主要优点 在(发达国家)如美国,日本与欧洲国家,超临界锅炉已自上世纪60年代以来发达。数据与经验证明,超临界机组具有经济与环境保护得巨大优势。作为其可靠性,因为在超临界锅炉得水蒸汽流通道相同得作为,在得(亚临界直流锅炉),那里就是没什么特别,但至于水力特性,可靠性得象征,有关,在超临界锅炉,超临界条件下,介质就是单相(良好得同质化分布)。从而避免了汽相、水相分布不均造成得问题。这就是承认,如果(全过程管理加强),超临界与亚临界机组可以得到一个极好得可靠性指标。 A、good homogenization of distribution 良好得均匀分布 B、some advanced countries一些发达国家 C、whole process management is strengthened全过程管理加强 D、great advantages on economy and environmental protection具有经济与环境保护得巨大优势 E、subcritical once-through boiler亚临界直流锅炉 P3 Circuit breaker Circuit breakers are automatically operated high voltage (or high current) switches、Circuit breakers are required (to control electrical power networks)by switching circuits on, by carrying load and by switching circuits off under manual or automatic supervision、Their duty is as follows: In closed position the circuit breaker must be a good conductor for the normal load current、In operating the circuit breaker must be able contacts shall have full insulation level、At operation the circuit breaker must close be able (to switch the current which can be from a few amperes)to many thousands of amperes, and independently of the characteristics from purely inductive to fully capacitive、At closing operation the circuit breaker must close fast and be safe also against full short circuit conditions、They must, therefore, be effective instantaneously when are called upon (to perform any switching operation after long
自测题（一） 电力系统的基本知识 一、 单项选择题（下面每个小题的四个选项中，只有一个是正确的，请你在答题区填入正确答案的序号，每小题2.5分，共50分） 1、对电力系统的基本要求是（ ）。 A 、保证对用户的供电可靠性和电能质量，提高电力系统运行的经济性，减少对环境的不良影响； B 、保证对用户的供电可靠性和电能质量； C 、保证对用户的供电可靠性，提高系统运行的经济性； D 、保证对用户的供电可靠性。 2、停电有可能导致人员伤亡或主要生产设备损坏的用户的用电设备属于（ ）。 A 、一级负荷； B 、二级负荷； C 、三级负荷； D 、特级负荷。 3、对于供电可靠性，下述说法中正确的是（ ）。 A 、所有负荷都应当做到在任何情况下不中断供电； B 、一级和二级负荷应当在任何情况下不中断供电； C 、除一级负荷不允许中断供电外，其它负荷随时可以中断供电； D 、一级负荷在任何情况下都不允许中断供电、二级负荷应尽可能不停电、三级负荷可以根据系统运行情况随时停电。 4、衡量电能质量的技术指标是（ ）。 A 、电压偏移、频率偏移、网损率； B 、电压偏移、频率偏移、电压畸变率； C 、厂用电率、燃料消耗率、网损率； D 、厂用电率、网损率、电压畸变率 5、用于电能远距离输送的线路称为（ ）。 A 、配电线路； B 、直配线路； C 、输电线路； D 、输配电线路。 6、关于变压器，下述说法中错误的是（ ） A 、对电压进行变化，升高电压满足大容量远距离输电的需要，降低电压满足用电的需求； B 、变压器不仅可以对电压大小进行变换，也可以对功率大小进行变换； C 、当变压器原边绕组与发电机直接相连时（发电厂升压变压器的低压绕组），变压器原边绕组的额定电压应与发电机额定电压相同； D 、变压器的副边绕组额定电压一般应为用电设备额定电压的1.1倍。 7、衡量电力系统运行经济性的主要指标是（ ）。 A 、燃料消耗率、厂用电率、网损率； B 、燃料消耗率、建设投资、网损率； C 、网损率、建设投资、电压畸变率； D 、网损率、占地面积、建设投资。 8、关于联合电力系统，下述说法中错误的是（ ）。 A 、联合电力系统可以更好地合理利用能源； B 、在满足负荷要求的情况下，联合电力系统的装机容量可以减少； C 、联合电力系统可以提高供电可靠性和电能质量； D 、联合电力系统不利于装设效率较高的大容量机组。 9、我国目前电力系统的最高电压等级是（ ）。 A 、交流500kv ，直流kv 500 ；
《电力系统潮流上机》课程设计报告 院系：电气工程学院 班级：电088班 学号： 0812002221 学生姓名：刘东昇 指导教师：张新松 设计周数：两周 日期：2010年 12 月 25 日
一、课程设计的目的与要求 目的：培养学生的电力系统潮流计算机编程能力，掌握计算机潮流计算的相关知识 要求：基本要求： 1.编写潮流计算程序； 2.在计算机上调试通过； 3.运行程序并计算出正确结果； 4.写出课程设计报告 二、设计步骤： 1.根据给定的参数或工程具体要求（如图），收集和查阅资料；学习相关软件（软件自选：本设计选择Matlab进行设计）。 2.在给定的电力网络上画出等值电路图。 3.运用计算机进行潮流计算。 4.编写设计说明书。 三、设计原理 1．牛顿-拉夫逊原理 牛顿迭代法是取x0 之后，在这个基础上，找到比x0 更接近的方程的跟，一步一步迭代，从而找到更接近方程根的近似跟。牛顿迭代法是求方程根的重要方法之一，其最大优点是在方程f(x) = 0 的单根附近具有平方收敛，而且该法还可以用来求方程的重根、复根。电力系统潮流计算，一般来说，各个母线所供负荷的功率是已知的，各个节点电压是未知的（平衡节点外）可以根据网络结构形成节点导纳矩阵，然后由节点导纳矩阵列写功率方程，由于功率方程里功率是已知的，电压的幅值和相角是未知的，这样潮流计算的问题就转化为求解非线性方程组的问题了。为了便于用迭代法解方程组，需要将上述功率方程改写成功率平衡方程，并对功率平衡方程求偏导，得出对应的雅可比矩阵，给未知节点赋电压初值，一般为
额定电压，将初值带入功率平衡方程，得到功率不平衡量，这样由功率不平衡量、雅可比矩阵、节点电压不平衡量（未知的）构成了误差方程，解误差方程，得到节点电压不平衡量，节点电压加上节点电压不平衡量构成新的节点电压初值，将新的初值带入原来的功率平衡方程，并重新形成雅可比矩阵，然后计算新的电压不平衡量，这样不断迭代，不断修正，一般迭代三到五次就能收敛。 牛顿—拉夫逊迭代法的一般步骤： （1）形成各节点导纳矩阵Y。 （2）设个节点电压的初始值U和相角初始值e 还有迭代次数初值为0。 （3）计算各个节点的功率不平衡量。 （4）根据收敛条件判断是否满足，若不满足则向下进行。 （5）计算雅可比矩阵中的各元素。 （6）修正方程式个节点电压 （7）利用新值自第（3）步开始进入下一次迭代，直至达到精度退出循环。 （8）计算平衡节点输出功率和各线路功率 2．网络节点的优化 １）静态地按最少出线支路数编号 这种方法由称为静态优化法。在编号以前。首先统计电力网络个节点的出线支路数，然后，按出线支路数有少到多的节点顺序编号。当由n 个节点的出线支路相同时，则可以按任意次序对这n 个节点进行编号。这种编号方法的根据是导纳矩阵中，出线支路数最少的节点所对应的行中非零元素也２）动态地按增加出线支路数最少编号在上述的方法中，各节点的出线支路数是按原始网络统计出来的，在编号过程中认为固定不变的，事实上，在节点消去过程中，每消去一个节点以后，与该节点相连的各节点的出线支路数将发生变化(增加，减少或保持不变)。因此，如果每消去一个节点后，立即修正尚未编号节点的出线支路数，然后选其中支路数最少的一个节点进行编号，就可以预期得到更好的效果，动态按最少出线支路数编号方法的特点就是按出线最少原则编号时考虑了消去过程中各节点出线支路数目的变动情况。 3．MATLAB编程应用 Matlab 是“Matrix Laboratory”的缩写，主要包括：一般数值分析，矩阵运算、数字信号处理、建模、系统控制、优化和图形显示等应用程序。由于使用Matlab 编程运算与人进行科学计算的思路和表达方式完全一致，所以不像学习高级语言那样难于掌握，而且编程效率和计算效率极高，还可在计算机上直接输出结果和精美的图形拷贝，所以它的确为一高效的科研助手。 四、设计内容
补全短文 A 3.A brief introduction (1)B:some advanced (2)D:great advantages (3)E:subcritical (4)A:good homogenization (5)C:whole process C 18.Copyright piracy (1)B:the research and (2)D:the fake and (3)A:new chemicals (4)E:the intellectual (5)C:physical property 5.Circuit breaker (1)B:to control (2)D:to switch (3)A:to perform (4)E:of the highest (5)C:of the circuit breaker E 17.Electric power (1)C:the lack of electricity (2)B:its unavailability (3)D:social disorder (4)A:its growth rate (5)E:high electric power 19.Electrical energy (1)D:static electricity (2)E:electrical charge (3)B:electrical energy (4)A:Alternating current (5)C:Electrical potential 21.Electrical conservation (1)C:reducing energy (2)D:making use (3)E:contributing (4)A:turning the (5)B:looking for F 1.Functions of power (1)C:power transmission (2)E:power networks (3)A:step-down (4)D:transmission (5)B:power network 7.Fuel cells (1)B:there is no (2)A:further (3)E:as they are (4)C:many cells (5)D:supply H 10.Hibernation (1)E:They can (2)B:We call (3)D:Hibernating (4)A:So they (5)C:As it O 9.Overcoming the Problem (1)C:there is still (2)A:there is no (3)D:it can be (4)E:more and more (5)B:building beautiful S 1.Substation misoperation (1)C:accidents (2)E:the grounding wire (3)A:preventing (4)B:the closing of (5)D:the persons from 8.Substations pace (1)C:composed of (2)A:substation automation (3)E:all of which (4)B:simulation training (5)D:a full-digital 4.Steam generation (1)B:an electrically (2)E:the fuel (3)A:first generating (4)D:the new gengrating (5)C:use of steam 11.Satellites (1)B:It circles the Earth (2)D:A satellite stays (3)A:The bigger (4)C:To get out (5)E:Artificial 12.Secondary equipment (1)B:the equipments provide (2)D:the equipments send (3)E:current values (4)A:5A rated current (5)C:50V rated voltage 13.Switching overvoltage (1)E:by the operation (2)A:determine (3)B:the cost of (4)C:at both (5)D:by means of 20.Solar energy (1)A:sustainable (2)D:the best known (3)B:inefficient (4)C:the collected energy (5)E: efficient T 14.Transmission line (1)A:transmitted from (2)D:the power line (3)B:the overhead (4)C:lightning frequently (5)E:large spanning 15.Transformer insulation (1)C:The internal insulation (2)E:The main refers to (3)A:The main materials (4)B:The degradation (5)D:If the winding 16.The electricity market (1)B:a wholesale market (2)D:a retail market (3)A:to agree on the (4)E:to choose (5)C:to register as 6.The ratio of distance (1)B:is used to (2)D:is the ratio (3)A:is moste (4)C:is not desirable (5)E:is the best