专业英语演讲稿及翻译

时间:2021-01-30 11:26:12 英语演讲稿 我要投稿

专业英语演讲稿及翻译

  篇一:专业英语演讲稿

专业英语演讲稿及翻译

  英国教育体制简介

  Ladies and Gentlemen:

  Today I want to talk something about British education system. 英国是一个有悠久教育传统的国家。它的教育体系经过几百年的沿革,相当的完善和复杂,且具有非常大的灵活性。可大致分为四个部分:学龄前教育、学校教育(义务教育)、延续教育、高等教育。

  第一部分:学龄前教育,即幼儿园教育。一般是为5岁以下的儿童开设的,没有具体的教学,目的是使他们在读小学时更能适应学校生活。

  第二部分:义务教育.1-6年级为一个档次,其实就是幼儿园的等级,所以并没有具体的教学。

  7-9年级为一个档次。与我国小学类似,开始学习所有科目,但并不非常注重学习成绩,算是一种开导式教育以培养兴趣,故基础教育扎实度与国内不可相比。

  10-11年级被称为GCSE,类似我国的初中。此时已经开始注重学生自己的兴趣培养,除了语文(英语),数学,外语(法语)之外,必修的为物理、生物、化学、电脑、体育。其他按照自己兴趣,选修三门科目。其范围非常广泛,美术、音乐、地理、拉丁、德语、体育理论、商业、经济等。所以学生可以不用为自己之前所不擅长的课再担心了。GCSE在英国也称第四级和第五级,中国学生进入该课程的年龄为14-15岁,此为两年的一贯课程科,在上GCSE可趁第二年的五月份时会有一次英国GCSE课程国家大会考。英国学生完成GCSE离开学校后可直接进入就业市场,想升大学者就会继续修读第六级的A-level课程。

  第三部分:延续教育。16岁到大学前的教育。这是英国教育体系中最有特色也最精彩的部分,它是继小学中学教育之后的第三级教育。为进入高等教育或者就业打下基础。它分为两种体系:学业路线和职业路线。学业路线着重于培养学术研究方面的人才,职业路线则结合社会各层面的职业需要,培养在各种行业中具有专门技能知识的人才。

  1、 学业路线。A-level的全称是“普通教育高级证书”,是学业路线的重要阶段,学制一般为两年。它总共有100多个科目,专业分科极为细致,它不像我国学生在高中学习的课程。而更像是大学的基础课,相当于中国大学本科课程的首两年。

  AS-level是A-level课程的一个特别组成部分,一门AS-level科目在内容和分量上相当于一门A-level科目的一半,深度和难度上与A-level相当。A-level课程的学生第一年都将从AS-level科目开始学习,所有学生必须选修四门以上不同的AS-level科目。而在第二年再确定只选三门A-level科目。

  2、职业路线。英国的职业教育可谓丰富多彩,从美容师到平面美术设计师、从婴儿护理到飞机维修师应有尽有。英国的职业教育与学业路线有一定的对应性,学生可以根据自己的学业情况选择进入学业路线的不同阶段。这种方式给学生提供了更多的选择机会,使不同类型的学生能够充分发挥自己的优势和潜能。

  GNVQ国家通用职业文凭。它是一种广泛的职业教育课程,与学业路线中的GCSE和A-level相平行,但在学业深度和难度上并不亚于这类课程。它的学习的方式灵活多样,学生可以根据自己的需要和兴趣爱好安排课程,选择学分制或模块式的学习方式,甚至可以在学习的过程中穿插工作,在学习和工作同时进行的

  过程中最终选择自己最喜欢的事业。GNVQ的选科比较简单,每门课程就是一个专业,所有受到许多英国学生和中国留学生的青睐。

  第四部分:高等教育。顾名思义,高等教育是英国教育体系中的高级阶段,它包括:

  本科(Bachelor Degree) 英国本科学士学位学制一般为三年,但有些大学的某些特殊专业要求读四年或以上,如牙科。在英国人眼中,医科和法律专业是最难考取也是最难读的专业。因为这两种学科的共同点是“人命关天”。

  研究生(Master Degree) 英国的研究生课程只需要一年时间,这与中国和美国都不同。在这一年里学生主要是写论文和做课题研究,课堂教学较少,因此其他国家的留学生如果没有在英国经过一段时间的学习或语言不过关,是很难完成这一年课程的。

  博士生(Doctorial Degree)

  高级国家文凭(HND-Higher National Diploma)。

  HND也是一种非常有用的文凭。它是职业教育体系中的最高阶段,学制一般为两年。HND理论上相当于中国的大专文凭,但分类更细,专业性更强。进入HND要求已经完成A-Level或者GNVQ-Advanced的课程,中国的'高中学生如果在某些方面(比如计算机)有特殊专长并且表现出相当好的语言能力的话,也有可能直接进入HND,但读起来会相当辛苦。

  HND毕业后,如果取得比较好的成绩,可以选择直接进入本科第三年的课程,通常是本校或联校的相应专业。也就是说,再加一年就可以取得学士学位。但英国最好的大学一般不接受此类学生。

  大学每学年分为了3学期。第一学期为9月中至圣诞节(约12月中);第二学期为1月中至万圣节(约4月中);第三学期为5月初。教学段是第一和第二学期,第三学期属于考试。

  UCAS

  是大学院校入学委员会,为想至英国修读大学课程的学生提供申请入学服务。对336所大学院校之申请,皆必须通过UCAS,学生并不能自己向学校直接申请。 UCAS有一点类似中国的大学高考,两者最大的不同是高考需要经由联考,而UCAS只是申请。经由UCAS需填写一份申请表(UCAS Form),表格内可填写6个大学,亦即最多可同时向六所大学提出申请,也可以只申请一所大学。UCAS Form上六所大学排列的顺序不是学生选择的优先级,优先次序是在学生收到大学的offer letter后自行决定。

  篇二:专业英语演讲稿

  Part 1 The Introduction Of Rose garden

  For centuries, there are many fairy tale about rose or take place in the rose garden, such as[The Nightingale And The Rose],you must heard of it, the nightingale made a red rose for the young man with her own blood with singing all night, it’s a sad story. What’s more, the story[Wild Swan],at the end of the story, princess sat on the rose blush with her swan brothers, what a romantic picture.

  Today, as far as I am concerned, many girls must have a dream of having a wedding with plenty of roses, or being a beautiful bride like a fresh rose, what’s more, living in a rose garden with the beloved one and so on. In a conclusion, rose is a symbol of beauty and love, it express the best wish of having a romantic life and the emotion.

  Here is a brief introduction of rose, it is a woody perennial of the genus Rosa. There are more than 100 species in the world, gardeners plant them to build a rose garden. So now, I’ll leave the stage to my partner Cai jun, she will tell us something about instance analysis.

  Part 2 Instance analysis

  Ok this part, I will give an example to discuss the Rose Garden.

  First, it’s a brief introduction about QingHai Rose Garden

  It is part of low density and top housing estate, with large space occupation, simple style of England in QingHai.

  Then Let’s see some roses applications in this community.

  It’s divides into two parts: To start with, planting in house to decorate room make people happy. On the other hand, a large area of cultivation to develop the secondary industry such as tea making. Closing to nature make people feel more comfortable.

  Meanwhile, rose garden has high collectable, attract the crows admire and form a senic spot. In addition drive more and more people purchase it, promote the local economic growth.

  However, everything has two sides. Rose garden not only increase the project costing unintentionally, but also has high requirements of the geographical conditions. And high price to limit consumers.

  That’s all what i want to say.

  Next then, welcome my partner explain the design of Rose Garden.

  Part 3 The layout of rose garden

  The layout of rose garden contains four parts: pergola, lattice well, flowers hedge and others.

  (I draw some pictures to help us to understand it.)

  Pergola: First, plant rose from both sides of pergola; then, lead the branch grows with it. Lattice well: This is the iron wire. Iron wire is utilized to make reticulation. The green stems could be coiled around the iron wire. Lattice well will be done about three years.

  Flowers hedge: There is a same way as the pergola to make a hedge.

  Others: you can also use roses to make some animal shapes.

  Such as: rabbit, hippocampus……

  The rose garden is done after collocate with garden lights, furniture, lattice well, flower

  hedge, pergola and awning. You can have a barbecue in the rose garden with friends.

  Part 4 The most popular rose

  Good evening, everyone, tonight I'd like to say something about the most popular rose. As we all known ,there are many kinds of roses, the red rose, blue rose, white rose, green roses and purple rose, black rose, yellow rose, rainbow rose. Now, Let's take a look some the most popular roses.

  Look at the picture ,it called Blue enchantress . we can rarely see a natural blue rose, when a white rose quickly to the flowering, watering it with dyes, because absorbs the dyes, and finally it turned blue

  Blue enchantress means pure love and sincere love.

  Next one, Avalanche. Avalanche is one of white roses, it Commonly used in modern fashion wedding. it’s price is higher than common White rose.

  This is Roasted rose, Roasted rose can adaptation for climate to grow in many

  country, it can be widely used in rose’s deep Processing. It’s a rare superior varieties of agricultural

  Then, Champagne roses: Champagne roses is The national flower of Bulgaria.

  Some people say wishing on a champagne roses can be achieved, so it called happy flower . Corolla:

  Corolla rose is the patent product of the United States, belong to the top

  varieties of red roses

  Bulgaria rose:

  Bulgaria rose is the best varieties rose for essence oil and production rose pure water, it has very highly economic value.

  Thank you for your attention, now welcome to my group members huang li chun To Introduction more about rose.

  Part 5 other five popular rose.

  Blue Moon, Sweet pretty, Alba Meialandina, Horatio Nelson and Sun Sprinkles are also very popular among people.

  Blue line rose have a fresh color like lavender, charming and make your feel romantic. It is popular in northern city and easily survival.

  Sweet Pretty

  It has a little of petals but has a number of flowers and like the butterflies dancing on the green leaves. You can see the stamen very clearly and the twigs are soft.

  Alba Meialandina

  The white color looks simple but elegant. It can serve as the potted plant and bedding plant. Horatio Nelson

  It cultivates from England. Both cold-consistence and disease -consistence are very good. It can use to decorate the wood-fence and act as the cut flower.

  Sun Sprinkles

  These flowers have thin petals, but have long flowering phase.

  The color of flowers like the sunlight, let us feel warm. People often use to decorate the arch.

  The most popular rose

  Part 6

  Today I will introduce five methods of growing roses; seedling、cuttage、grafting、marcottage and root division.

  The commonest form is generative propagation. Generally, it is used for cultivation of new cultivars, we can put the seeds picking in the autumn in plastic bags with wet soil. Placed in circadian rhythma. After a month heating up the temperature to 20℃ gradually, wait it rupture and sprout.

  Cuttage

  Twig cottage: choose the sprout buds in early spring, disbranch few xylom from stem, deal with growth hormone then nursery beds.

  Stiff wood cottage: cut the substantial branch overwintering place in low temperature romm and upside down wet sand. Next spring transplant to nursery beds.

  Stiff wood hygroscopic: choose the branch with one or two leaves, cut the bottom, stick in the water, put it in 15℃—20℃ with sunshine, it can promote proliferate.

  Grafting include budding、branch grafting and root grafting.

  There are two ways to marcottage, one is on the ground, the other one in the air. During the rose growing time, carve branch, curve it cover wet soil, when the wound outgrow new root, cut down and transplant. The second method we can choose a suitable position on train rose carve branch or peel off the skin. Put a packet of soil around it about a month, cut down when it have root.

  The last one is root division. Plant the roses deeply, urge branch grow root, cut the new root with the lateral branch to get a new one.

  Here are the five kinds of planting roses, thank you for your attention

  .

  Part 7 how to control diseases and insect pests

  There are often two kinds of diseases infect rose, powdery mildew and downy mildew. The powdery mildew often appears in new leaves in early spring and late autumn. It’s a kind of spore flow with the air. Spraying water frequently can prevent the disease. And the infected leaves must be cut immediately once the rose was ill. The downy mildew will hurt the leaves, petals, shoots, pedicels. The humidity should be controlled under 85% to prevent downy mildew and don’t use too much nitrogenous fertilizer to prevent the disease.

  And there are two kinds of insect pests often hurt rose, aphid and red spider. Aphid can appear in any time during a year. It will be threaten when weather is dry. Pesticide should be sprayed in the growing point and back of leaves to control the pest. Red spider will suck up chlorophyll of leaves. And pesticide should be sprayed at the early stage of the illness.

  篇三:专业英语演讲稿

  INTRODUCTION

  The operational [??p??rei??n?l] amplifier [??mpl??fa??] is an extremely efficient and versatile [?v?:s?tail] 通用device. Its applications span the broad electronic industry filling requirements for signal conditioning, special transfer functions, analog [??n??l?:g] 模拟instrumentation, analog computation, and special systems design. The analog assets [??set ] of simplicity [sim?plisiti] and precision characterize circuits

  [?s?:kit]utilizing [?ju:tilaiz] operational amplifiers.

  运算放大器是一个非常有效和通用设备。它的应用范围广泛的电子工业,信号调理,专项转移功能,模拟仪表,模拟计算,及特殊系统设计的灌装要求。简单性和精确度是使用运算放大器的模拟电路特点

  The Feedback Technique

  The precision and flexibility of the operational amplifier is a direct result of the use of negative feedback. Generally speaking, amplifiers employing feedback will have superior operating characteristics at a sacrifice [?s?krifais]of gain.

  在运算放大器的精度和灵活性是利用负反馈的直接结果。一般来说,采用反馈的放大器有卓越的经营特点,在牺牲增益的代价下。

  With enough feedback, the closed loop amplifier characteristics become a function of the feedback elements. In the typical feedback circuit, figure 1, the feedback elements are two resistors. The precision of the “closed loop” gain is set by the ratio [?rei?i?u] 比率of the two resistors and is practically independent of the “open loop” amplifier. Thus, amplification to almost any degree of precision can be achieved with ease.

  有了足够的反馈,闭环放大器的特点成为一个功能的反馈元件。在典型的反馈电路中,图1中,反馈元件是两个电阻器。的精度的“闭环”的增益设置的两个电阻的比率实际上是独立的“开环”放大器。因此,放大到几乎任何的精确度,可以容易地实现。

  Notation符号

  ?= Symbol (a) is a buffer [?b?f?] 缓冲器 op工作 amp放大器

  ?= Symbol (b) is a differential input, single ended output op amp. This symbol represents the most common types of op amps, including voltage feedback, and current feedback. It is often times pictured with the non-inverting input at the top and the inverting input at the bottom.

  ?= Symbol (c) is a differential input, differential output op amp. The outputs can be thought of as “inverting” [in?v?:t] 反转and “non-inverting”, and are shown across from

  the opposite [??p?zit]相反 polarity [p???l?r?ti] 极性 input for easy completion

  [k?m?pli:??n] 完成of feedback loops on schematics [ski:?m?t?k].

  符号(a)是一个缓冲器的运算放大器

  ?=符号(b)是一个差分输入,单端输出的运算放大器。这个符号代表最常见的类型,包括电压反馈和电流反馈运算放大器。它通常是在顶部和在底部的倒相输入端与非反相输入描绘的时间。

  ?=符号(C)是差分输入,差分输出运算放大器。输出可以被认为是“反转”和“非反相”,并示出从相反的极性的输入对面容易完成的反馈回路原理图

  Power Connections电源连接

  Power is supplied to each of these units at connections as shown in figure 4. Such a connection is implied in all operational amplifier circuits. The dual [?dju:?l]两部分

  supply presents the same absolute value of voltage to ground from either side, while the center connection ultimately ['?ltim?tli]最宗defines the common line and ground potential. The exceptions to this are AC amplifier circuits that may use a single power supply. This is accomplished by creating a floating [?fl??t??] AC ground with DC blocking capacitors. In such circuits, a source of “half-supply” creates a “virtual ground” exactly half way between the positive supply and ground potentials.

  电源供给到这些单元中的每一个,如在图4中所示的连接。这样的连接是隐含在所有的运算放大器电路。双电源呈现相同的绝对电压值从任一侧接地,而中心连接最终定义的公共线和接地电位。例外情况是可以使用单个电源的AC放大器电路。这是通过创建一个浮动的AC地面的隔直流电容器。在这种电路中,“半电源”的来源创建一个“虚拟地”正好有一半之间的正电源和接地电位的方法。

  Electrical Circuit Models电气电路模型

  The simplified models of the differential [?d?f??ren??l] 差分input operational amplifiers are shown in figures 6 and 7.

  在图6和图7中示出的差分输入运算放大器的简化模型。

  As indicated in figure 6, the operational amplifier can be represented by an ideal voltage source whose value depends on the input voltage appearing across the inverting and non-inverting inputs plus the effects of finite [?fainait] 有限input and output impedances [im?pi:d?ns]阻抗. The value, A, is known as the open loop (without feedback) gain of the operational amplifier.

  正如在图6中所示,运算放大器可以表示为一个理想电压源,其值取决于对输入电压的两端出现的反相和非反相输入端加上有限的输入和输出阻抗的影响。值,A,是被称为在运算放大器的开环增益(没有反馈)。

  The simplified model of the differential output operational amplifier (figure 7) is an accurate [??kjurit] approximation [??pr?ks??me???n] 近似值only under special conditions of feedback (see “Balanced Amplifier” later in this handbook). Figure 6 represents the model of the differential output type when it is used as a single ended output device; the inverting output simply being ignored.

  简化模型的差分输出运算放大器(图7)是一个准确近似,仅在特殊条件下的反馈(见“平衡放大器”,在本手册后面)。图6表示的差分输出的模型类型时,它被用作一个单端输出的移动设备简单地被忽略的反相输出。

  The Ideal Operational Amplifier理想运算放大器

  In order to introduce operational amplifier circuitry, we will use an ideal model of the operational amplifier to simplify the mathematics [?m?θi?m?tiks] involved in deriving gain expressions, etc., for the circuits presented. With this understanding as a basis, it will be convenient to describe the properties of the real devices themselves in later sections, and finally to investigate circuits utilizing practical operational amplifiers. 为了介绍运算放大器电路中,我们将使用一个理想的模型简化中获得的电路增益表达式等,所涉及的数学运算放大器的。有了这样的认识,以此为基础,可以方便的真实设备本身在后面的章节中描述的属性,最后调查利用实际的运算放大器电路。

  To begin the presentation of operational amplifier circuitry [?s?:kitri], then, it is necessary first of all to define the properties of a mythical “perfect” operational amplifier. The model of an ideal operational amplifier is shown in figure 9.

  首先介绍运算放大器电路,那么,它是必要的,首先要定义一个神话般的“完美”的运算放大器的性能。理想的运算放大器的模型是在图9中所示。

  Defining the Ideal Operational Amplifier

  ?= Gain: The primary function of an amplifier is to amplify, so the more gain the better. It can always be reduced with external circuitry, so we assume gain to be infinite

  [?infinit]无限.

  增益:放大器的主要功能是放大的,所以更多的获得更好。它总是可以减少与外部电路,所以我们假设增益是无限

  ?= Input Impedance: Input impedance is assumed to be infinite. This is so the driving source won’t be affected by power being drawn by the ideal operational amplifier. 输入阻抗:输入阻抗被认为是无限的。这是这样的驱动源将不会受到影响被绘制了理想的运算放大器的功率。

  ?= Output Impedance: The output impedance of the ideal operational amplifier is assumed to be zero. It then can supply as much current as necessary to the load being driven.

  输出阻抗:理想的运算放大器的输出阻抗被假定为零。然后,它可以提供尽可能多的电流所必需的被驱动的负载。

  ?= Response Time: The output must occur at the same time as the inverting input so the response time is assumed to be zero. Phase shift will be 180?. Frequency response will be flat and bandwidth infinite because AC will be simply a rapidly varying DC level to the ideal amplifier.

  响应时间:输出必须在相同的时间发生的反相输入端,这样的响应时间被假定为零。相移为180?。频率响应是平的,无限的,因为交流会只是一个快速变化的DC电平的理想放大器的带宽。

  ?= Offset: The amplifier output will be zero when a zero signal appears between the inverting and non-inverting inputs.

  偏移量:当一个零信号之间出现的反相和非反相输入端,放大器的输出将为零。

  CIRCUITS AND ANALYSES USING THE IDEAL OPERATIONAL AMPLIFIER用理想运算放大器的电路及分析

  The Desirability of Feedback是可取的反馈

  Consider the open loop amplifier used in the circuit of figure 10. Note that no current flows from the source into the inverting input - the summing point restraint derived in the previous section - hence, there is no voltage drop across RS and ES appears across the amplifier input. When ES is zero, the output is zero. If ES takes on any non-zero value, the output voltage increases to saturation [?s?t???re???n] 饱和, and the amplifier acts as a switch.

  考虑图10的电路中使用的开环放大器。请注意,从源代码编译成的反相输入端 - 来自上一节中的求和点约束 - 因此没有电流流过,有没有RS两端的电压降和ES出现整个放大器的输入。当ES是零,其输出为零。如果ES承担任何非零的值,输出电压增大到饱和,该放大器作为一个开关。

  The open loop amplifier is not practical - once an op amp is pushed to saturation, its behavior is unpredictable. Recovery time from saturation is not specified for op amps (except voltage limiting types). It may not recover at all; the output may latch up. The output structure of some op amps, particularly rail-to-rail models, may draw a lot of current as the output stage attempts to drive to one or the other rail. For more details on op amps in open loop operation, consult reference 1.

  开环放大器是不实际的 - 一旦一个运算放大器推到饱和,它的行为是不可预测的。未指定恢复时间从饱和运算放大器的(除了电压限制类型)。它可能无法收回;输出锁存。作为输出级试图把车开到一个或其他铁路的一些运算放大器,尤其是轨到轨车型,可能会吸引大量的电流输出结构。对于运算放大器开环运行的详细信息,请参阅参考文献1。

  Two Important Feedback Circuits

  篇四:专业英语演讲稿范文

  专业英语演讲稿范文

  feet, the carriers of life

  good morning, ladies and gentlemen.

  i would like to tell you about an unusual assignment. i was surprised and amused when our teacher told us our homework was to wash our feet carefully .

  yeah, washing the feet is such a common daily activity that i’ve never paid much attention to it. my feet had been cooperating and helping each other, nearly always managing to get washed, while i was enjoying my readings. but that night, while i gently touched my feet in the hot water, i realized how nice and cozy bathing my feet could be.

  deep in my mind, the hands always seemed superior to the feet. people use all sorts of things from soap to moisture cream to protect their hands. the feet become, kind of, neglected, since the feet spend all day long with the ground and dirt, and quite inevitably, get really smelly.

  as i slowly soaped and rinsed my feet, i was beginning to

  understand why my teacher launched such a mission. she wanted us to realize that the feet were more helpful than we had ever imagined.

  surely, the hands are important. however it’s the feet that carry your whole body weight, and everything about your life.

  the feet carry you, as well as your hopes and dreams, and walk steadily upon the most solid ground, moving forward step by step,

  upon mountains and down valleys, over the smooth as well as the rough, through the bitterness as well as the joy.

  as i was washing my feet, i let my mind wander. i felt as if i was on a vast desert. looking around, i saw millions of footprints, large and small, deep and shallow, being the marks of existence, and the traces of life. and there i was, using my own feet, making my own path, towards the oasis of life……

  thank you.

  脚,生命的载体

  女士们,先生们,上午好!

  我想告诉大家一份不寻常的家庭作业,老师布置我们当晚回家认真给自己洗一遍脚,听到后,我感到惊奇而有趣。

  是啊,脚,我每晚必洗,但从未重视过。洗脚时,我津津有味地看着书,任双脚摩挲,互帮互助。但今晚,当我的双手触摸到自己的双脚时,是多么的舒服、惬意啊!

  心中,总是觉得手比脚高贵,人们用香皂洗手,并抹上护手霜,百般呵护;而脚踩在地上,即使有鞋袜,也总被认为是与灰土打交道的粗笨一族,并有不可避免的异味,脚,似乎成了身体中被忽视的部分。

  我仔细地洗着脚,渐渐地,我明白了老师的用意:她布置这个特殊的任务,是为了让我们认识到脚,其实比我们想象的更伟大。

  无可争议,手固然重要。可脚却承担着你生命的全部重量。

  脚,负着你,你沉甸甸的希望和梦想,踩着踏实的大地,一步一步地前进,走上了高山也走下了峡谷,走过了平坦也走过了崎岖,走过了苦难也走过了幸福。

  我在洗脚,手脚依偎,恍惚间,我仿佛置身于广袤的大漠中。环视四周,一串串大大小小深深浅浅的脚印,这是存在的证明,生命的印迹。而我用自己的双脚,开辟着自己的道路,向生命的绿洲前进……

  谢谢!

  篇五:专业英语演讲稿

  Good morning! Ladies and gentlemen. Now I am standing here to give a report. The topic is Simulation of Temperature Field of Cable, and Liu Xingmou and Yang Chao are my partners.

  The content of this report is divided into five parts. The first part gives the introduction; the second part discusses the related theory; the third part establishes the geometric model; the fourth part gets the simulation result and the conclusions are given in the last part.

  Now let’s begin with the introduction. The extensive usage of underground power cables is a typical feature of modern power transmission and distribution networks. It is practically significant to bring in a rapid and real-time determination of the cable current carrying capacity. However, the temperature of cable core is one of the important parameters, and it can be used as an important basis of determination of the cable current carrying capacity. So simulation of temperature of cable is very necessary. Over the past years, two methods have been developed to calculate the cable current-carrying capability. One is the IEC60287-based thermal analysis method, which is based on the geographical position and meteorological condition of laying region. Another is the numerical calculation method, which analyzes the temperature distribution of cables and their laying area in the light of the theory of temperature field. It is advised to take advantage of the finite element method here, due to its ability to layout the grid nodes arbitrarily.

  Now let’s begin with the second part: theory. Based on the principle of heat transfer, it can be known that the associated steady-state heat conduction equation for two-dimensional underground cable system can be described as

  ?(?T

  ?x22??T?y22)?qv?0

  Where T denotes the unknown temperature, ?denotes thermal conductivity, qv is the heat

  source generated by cables. The boundary conditions are very often of three common categories T(x,y)|??f(x,y)|?

  ??T?n?T

  ?n|??qn?0|??h(T?Tf)|???

  Where ?is integral boundary, h is heat transfer coefficient and qn is density of heat flow rate.

  Now let’s begin with the third part: establishment of the geometric model. According to the structure parameters and laying parameters of the cable, a closed domain geometric model of the underground cable is established. Fig.1 shows the laying model of single-loop buried cables.

  Fig.1 Geometric laying model of single circuit loop buried cables

  As it is shown in Fig.1, Fig.1, d1, d2 and d3 represent, respectively, the cables spacing, the

  distance that from the cable to the left and right borders of the model and the buried depth.

  Now let’s begin with the fourth part: simulation. To calculate the temperature distribution of the cable, the type of 8.7/15kV YJV1×400 single-loop XLPE cable is taken for an example in this part. The structural parameters and laying parameters of the cable are described, respectively, in Table 1, 2.

  Table 1 Structural parameters of the cable

  Physical quantities

  Conductor diameter

  Insulation thickness

  Shielding layer thickness

  Protective covering thickness

  External diameter of the cable

  Parameter values 23.8mm 5.9mm 0.3mm 2.3mm 41.0mm

  The heat resource losses, which include conductor loss, insulating layer dielectric loss, the metallic sheath loss and shielding loss, can be calculate according to the IEC60287.

  The lower boundary belongs to the first category boundary condition, because constant temperature is taken. As the horizontal temperature gradient of left and right boundary is zero, so it belongs to the second category. The upper boundary belongs to the third category because the air temperature is 313K, which meets the convection boundary condition.

  According to the IEC-60287, the cable loss parameters are calculated. When I=680A, the temperature distribution of cable area is obtained correspondingly. The finally results are shown in figures. It is programmed by COMSOL software, and based on the principle of heat transfer and finite element method.

  Based on finite element method and the principle of heat transfer, a temperature field distribution model of underground cables is established by COMSOL software. This model can take account of laying condition and some influential factors, such as soil thermal resistance, the ambient temperature, heat external factors and so on. And it is practically significant to estimate cable current carrying capacity.

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