電氣工程與自動化專業變壓器電力變壓器的選擇和冷卻及斷路器畢業論文外

畢 業 設 計（論文）

外 文 文 獻 翻 譯

文獻、資料中文題目：

1.變壓器2.電力變壓器的選擇和冷卻3.斷路器

文獻、資料英文題目：

文獻、資料來源：

文獻、資料發表（出版）日期：

院 （部）：

專 業： 電氣工程與自動化

班 級：

姓 名：

學 號：

指導教師：

翻譯日期： 2017.02.14

本科畢業設計

外文文獻及譯文

文獻、資料題目：

《Special English for Architectural Electric

Engineering and Automation》

文獻、資料來源：

期刊（著作、網絡等）

外文文獻一：

Transformer

One of the most valuable apparatus in electric power system is the transformer,

for it enables us to utilize different voltage levels across the system for the most

economical value. Generation of power at the synchronous machine level is normally

at a relatively low voltage，which is most desirable economically．Stepping up of this

generated voltage to high voltage，extra-high voltage or even to ultra-high voltage is

done through power transformers to suit the power transmission requirement to

minimize loss and increa the transmission capacity of the lines．This transmission

voltage level is then stepped down in many stages for distribution and utilization

purpos．

A transformer is a static device for transferring electric energy from one circuit to

another electromagnetically，that is，by induction instead of by conduction．Its usual

function is to transfer energy between circuits of different voltage．A transformer has a

magnetic core on which there are two or more windings．The windings are insulated

from each other and from ground．In autotransformers，however，the windings are

connected together．The asmbly of core and coils is normally insulated and cooled

by immersion in mineral oil or other suitable liquid within an enclosing

tank．Connection to the windings is by means of insulating bushings，usually through

the cover.

The “ratio of transformation” is determined by the relative number of turns in

each of he windings．This is known as the “turn ratio” and it is the ratio of the no-load

voltages．When the unit is carrying load, the ratio of the actual voltages is slightly

different becau of the drop caud by the flow of 1oad current through the

impedance of the transformer windings．At rated load, this drop is known as the

"voltage regulation". The amount of voltage drop varies with the power factor of the

output even when the kilovolt-amperes remain constant．

Practically all power transformers and many distribution transformers have taps

in one or more windings for changing the turn ratio．Changing the ratio is desirable

for two reasons to compensate for varying voltage drop in the system and to assure

that the transformer operates as nearly as possible at the correct core density．For the

latter purpo, the taps should be in the winding subject to the voltage variation.

De-energized tap changers are ud when it is expected that the ratio will need to be

changed only infrequently, becau of load growth or some asonal change．The

desired tap is lected by means of a ratio adjuster(no load taps)．Load tap

changer(LTC)is ud when changes in ratio may be frequent or when it is undesirable

to de-energize the transformer to change a tap．It ldom makes much difference to

the ur which winding or windings are tapped；therefore，the choice is usually made

by the designer on the basis of cost and good design. Both winding current and

voltage must be considered when applying LTC equipment．High voltage and high

current applications require special considerations to arrive at an optimum location for

the LTC equipment．Step down units usually have LTC in the low-voltage winding

and de-energized taps in the high voltage winding．

When energy is to be transferred between two circuits of nearly the same

voltage．The u of autotransformers affords cost savings over two-winding units．The

nearer the voltages are to each other, the smaller will be the autotransformer per

kilovolt-ampere of output，and the greater the savings．The simplicity of phasing out

systems has incread its u．Most autotransformers are Y-connected，and it has been

a standard American practice to add a low capacity, delta winding．This is frequently

referred to as a “delta tertiary“．Its primary purpo has been to provide an internal

path for the third harmonic currents (required for excitation)，thus reducing tho

currents on the power system．It also helps to stabilize the neutral and to ground the

system better．In recent years，the u of shielded telephone cable has reduced the

requirements for the delta tertiary. Becau an autotransformer does not afford

electrical paration between the two circuits, disturbances originating on one circuit

can be communicated to the other．This difficulty is minimized by solidly grounding

the neutral of the autotransformer. Solidly grounding the neutral，however,

caus(among other things)current of short-circuit magnitude to flow through the

delta-connected tertiary winding during ground faults on either system.

Autotransformers are not inherently lf-protecting and, therefore，all windings must

be examined for mechanical strength as applied to the system where they will be ud .

Tertiaries are normally 35％of the physical size of the largest winding of the

autotransformer, unless otherwi specified by the ur.

The bulk of a11 transformers，except for large extra-high voltage(EHV)and

distribution units are three-pha units． In the early days of the industry，It was

almost universal practice in the United States to u three single-pha units

connected in a three-pha bank．Insulation clearances and shipping limitations for

certain large EHV units now require this design．The distribution systems rve

mainly single-pha loads in residential areas and are rved from single-pha

transformers．

中文譯文一

：

變壓器

在電力系統中最有價值的一個裝置是變壓器,因為它使我們能夠在系統中利

用不同的電壓水平獲得最經濟的價值。同步電機的發電電壓水平通常是在一個相

對較低的電壓,這是最令人滿意也是最經濟的。把發電電壓升高到高電壓,超高壓

甚至超高電壓是通過電源變壓器實現的,這樣可以適應電力傳輸要求,減少電壓

損失,提高線路的傳輸容量。在不同的階段，我們可以根據配電和使用目的的要

求把高電壓通過變壓器降到低電壓。

一個變壓器是一個靜態裝置，因為電能量從一個電路轉移到另一個電路是通

過電磁的形式實現的,也就是說,能量的轉移是通過感應而不是通過傳導。變壓器

通常的功能是傳遞不同電壓等級電路之間的能量。 變壓器有一個磁芯，磁芯上

有兩個或兩個以上的繞組，這些繞組相互之間是絕緣的并且與大地也是絕緣的。

然而自藕變壓器中的繞組是直接連在一起的的。 磁芯和繞組的組裝通常是在密

閉容器內進行的并且浸沒在礦物油或其他適當的液體中。線圈的連接是通過絕緣

套管,通常穿過表面。

“變壓比”是由每個繞組上線圈的相對匝數決定的。我們稱為“匝數比”,

這也是空載電壓比。當變壓器承載負荷時,實際電壓的比例略有不同,因為當負載

電流通過變壓器時會因為繞組阻抗而使電壓產生降落。在額定負載下,這種電壓

降落被稱為“電壓調整”。 電壓降落的大小隨輸出的功率因數的變化而變化即

使總的視在功率保持不變。

幾乎所有的電力變壓器和輸電變壓器在一個或多個線圈上都有改變變壓器

變比的開關。改變變比有兩個令人滿意的理由：補償系統中變化的電壓降落以及

確保變壓器盡可能的在正確的中心密度下操作。為了達到后邊的目的，改變變比

的開關通常放在變壓器的繞組中并且受電壓變化的控制。當變比不經常改變時，

例如負荷的增加或者季節的變化，我們常用斷距抽頭轉換開關。 理想的開關是

由比例調節器選擇的。當變比變化比較頻繁或者不希望斷開變壓器去改變抽頭

時，我們常用負載抽頭轉換開關(LTC)。 當線圈或線圈組都是抽頭時對使用者這

幾乎沒有任何區別；因此,設計師通常根據成本和良好的設計來做出選擇。應用

LTC設備時繞組電流和電壓都是必須考慮的。高電壓和大電流在應用中需要特殊

考慮才能達到負載抽頭轉換開關（LTC）設備的最佳使用條件。在降壓變壓器中，

低壓繞組通常用LTC（負載抽頭轉換開關），高壓繞組通常用斷距抽頭轉換開關。

當兩個具有相同的電壓的電路之間轉移能量時,使用自耦變壓器要比使用

兩個繞組單元更能夠節約成本。兩個電路的電壓越接近,自耦變壓器輸出的每千

伏安越小,也就越節約成本。一些簡單落后的系統往往常用它。很多自耦變壓器

是星形連接,這已經成為一個標準，但美國人嘗試采用低容量三角形連接的自耦

變壓器。這是經常被稱為是一個“三角洲三級“牽引,主要目的是為三次諧波(用

來激發)提供一個內部路徑,從而減少在電力系統的諧波。這也有助于穩定中性點

并且使接地系統更好的工作。在最近幾年,屏蔽電話電纜的使用已經降低了對三

角洲三級的要求。？？

因為一個自耦變壓器不負擔兩個電路之間的電氣隔離, 來源于一個電路的

干擾可以傳達到另一個電路。這一困難可以通過將自耦變壓器的中性點直接接地

來解決。然而,中性點直接接地,在系統發生接地故障時會(在其他事物之中)引起

短路電流流過三角接法的第三相繞組。第三繞組的物理尺寸通常為自耦變壓器最

大的繞組的35%,除非用戶另有指定。自耦變壓器就不具有自我保護的功能,因此,

所有的繞組在使用之前都必須經過機械強度檢查以確定是否適用于該系統。

？？除了大型超高壓(超高壓)和配電設備，大部分變壓器都是三相的。在美國早

期的工業中, 把三個單相單位連接成一個三相的組合設備是一個非常普遍的經

驗。某些大型超高壓單位的絕緣間隙和運輸限制現在就需要這個設計。配電系統

主要服務于居民區的單相負載并且電能是引自單相變壓器。

外文文獻二：

Selection and Cooling of Power Transformer

The lection of the transformer can have a major impact on the cost a

substation，since the transformer reprents the major cost item．Nameplate rating is

only a guide to transformer application，and should only be ud as a first step in the

lection process. The transformer is available as a lf-cooled unit，or it can be

purchad with additional steps of forced cooling that u fan or fans and oil

pumps．Transformer ratings can be incread from 25％ to 66％ by the addition of

fans and pumps．The nameplate rating is bad on a continuous load producing a 55℃

to 65℃ conductor temperature ri over ambient. Since many transformers do not

carry continuous loads，advantage can be gained from the thermal time lag to carry

higher peak loads without exceeding the temperature limits .Transformer ratings are

bad on the assumption that only an extremely slow deterioration of insulation will

take place with normal operation．A substantial increa in rating can be achieved by

accelerating the loss of insulation life．This increa in rating might approach 200％

for an hour or two, and approximately 120％for 24 hours．For substations that are

designed to carry full load under the outage of any one transformer, a high emergency

rating for a 24-hour period (e.g. until the failed unit can be replaced) could mean the

lection of smaller transformers and a substantial saving in substation cost．

The lection of the transformer should involve a careful evaluation of a number

of other factors：

(1)Impedances should be lected considering their effect on short-circuit duties

and low-side breaker ratings both for initial and future station developments．In

addition，impedance is important to achieve a proper load division in the parallel

operation of transformers.．

(2)No load tap ranges should be lected to provide an adequate low-side bus

voltage.

(3)If the high-side or low-side voltages vary over a wide range during the load

cycle, it may be necessary to provide bus regulation．The actual regulation can be

calculated using the system and load characteristics．If regulating equipment is

needed，it may be desirable to provide it in the transformer by using load tap

changer(LTC) equipment. If the need for bus regulation is not prently evident, but

may be required in the future, it may be economical to leave space in the station for

future regulators, and buy transformers without LTC equipment.

A great many transformers, including all the large ones and all the high voltage

ones are immerd in mineral oil which rves the double purpo of cooling and

insulating the windings. Small transformers have enough tank surface to radiate a11

the heat caud by their loss without exceeding the permissible temperature ri．As

size increas，the loss increa faster than the tank surface which soon becomes

inadequate．Various methods have been developed to get the heat out of the tank more

effectively．Large power transformer being built today are commonly of the

forced-oil-cooled type．In this design the oil is pumped both through the external

cooling devices(air or water heat-exchangers)and through internal channels that are

located nearest the points where the heat is generated．Thus the transfer of heat to and

from the oil is far more effective than in the plain lf-cooled or fan-cooled unit where

the oil is allowed to circulate by convection. When oil-to-air heat exchanger(a group

fans on each radiator)is ud，this cooling type is designated as type of FOA．While

oil-to-water heat exchanger is ud，it is called FOW．

For applications where any liquid，even a nonflammable one，is objectionable，

the dry-type transformer is ud．The ventilated dry-type unit is cooled by a

continuous natural draft of air and conquently is not suitable for locations where the

air is wet or dirty. For the locations a completely enclod unit，the aled dry-type，

is available，having a core-and-coil in a tank that is aled and filled with an insulating

gas. Dry-type transformers are completely nonflammable，using organic material such

as epoxy resin.

中文譯文二：

電力變壓器的選擇和冷卻

變壓器的選擇對變電所的建造成本具有重大影響,因為變壓器是主要的成

本項目。銘牌定額只是變壓器應用的指南,它只應該用作變壓器選擇過程的第一

步。變壓器可以是自冷式單位,也可以購買額外的冷卻裝置,如強制冷卻風機或機

組和柴油泵。根據額外的冷卻機組和柴油泵，變壓器評級可以從25%增加到66%。

銘牌評級是基于連續負荷產生超過環境55℃到65℃導體溫升而評定的。？？？

因為很多變壓器不帶連續負載,優勢可以獲得從熱滯后時間進行更高的高峰負荷

而不超過溫度限制。變壓器的評級是基于假設：正常操作下的絕緣老化只是一個

極其緩慢的過程。通過加速絕緣老化的進程可以大幅度的提高評定等級。在一兩

個小時左右評級可能增長接近200%,而在在二十四小時左右評級則增長大約

120%。因為變電站的設計要保證在任何一個變壓器斷電的情況下都要滿足全負荷

運行，為24變電站設計將滿載在停機的任何一個變壓器,因此在二十四小時內的

較高的緊急評級(例如直到失敗的單位可以更換)可能意味著選擇較小的變壓器

和節約大量的變電所成本。

變壓器的選擇應該涉及對其他影響因素的審慎評估:

(1)阻抗應該被選擇的考慮到他們對短路職責和下部斷路器評級的影響對初

始和未來空間站發展。此外,阻抗在并行變壓器的操作中獲得一個合適的負載也

是十分重要的.

(2)無載分接范圍應該選擇提供一個足夠的下部總線電壓。

(3)如果高壓側或低壓側電壓在負載周期內變化很大的話,可能有必要提供總

線監管。通過系統和負載特性實際監管和控制是可以被計算和描繪的。如果調節

設備是必要的,在變壓器內使用負載抽頭轉換開關(LTC)設備來提供監管是可取

的。如果需要總線監管目前是不需要的,但可能在未來需要的,那么在變電站預留

未來安裝設備的空間并且購買沒有LTC設備的變壓器是十分經濟的。

許多變壓器,包括所有的大體積的和所有的高電壓的變壓器都是沉浸在礦物

油,礦物油有雙重目的：冷卻和絕緣繞組。小變壓器有足夠的容器表面輻射a11

熱引起的損失而不超過容許溫度上升范圍。隨著體積的增加,損失增加的速度會

加快，這時容器表面會變得不適宜。很多的方法已經被改進以使的容器的散熱更

有效。今天一般建造的大型電力變壓器都是強制循環油冷卻類型的。在這個設計

中礦物油通過油泵不僅流進外部冷卻設備(空氣或水熱交換器)，而且流過內部最

靠近熱源的凹槽。因此通過礦物油對熱量進行轉移的方式要比一般的自冷裝置和

風冷裝置要有效的多,因為油是允許通過對流循環的。當油空氣熱交換器(在每個

散熱器有一組風機)被使用時,這種冷卻類型被指定為FOA。當油水熱交換器被使

用時，則被稱為FOW。

因為無論變壓器是采用何種液體都是不受歡迎的，即使這種液體不易燃，所

以干式變壓器得到普遍的應用。通風式的干式變壓器通常是通過自然風來使變壓

器冷卻的，所以這種變壓器不適于潮濕和惡劣的環境。如果鐵芯和線圈是在一個

充滿絕緣氣體的封閉裝置中則干式變壓器在潮濕惡劣環境中是完全可以正常運

行的的。干式變壓器是完全不燃燒的，因為它使用了有機材料如環氧樹脂。

外文文獻三：

Circuit Breaks

Within a few years of the introduction of the fu，the growing electrical industry

startedlooking for an alternative method of providing protection for electric

circuits．They wanted a device that would not be destroyed by its operation，that could

simply be ret to restore power, and that could also be ud as a means of switching

for the circuit．Out of this development work came the circuit breaker．which is an

electromechanical device．The circuit breaker is defined as a device designed to open

and clo a circuit by non-automatic means and to open the circuit automatically on a

predetermined over-current without injure to itlf when properly applied within its

rating.

As with other equipment，circuit breakers are divided into tho rated for 1 000

volts and less and tho rated for more than 1000 volts．Low-voltage circuit breakers

were also divided into two distinct categories，molded-ca and power

types．However，in the past few years the distinction between the two types has

become less clea-cut as a new type of encad breaker are universally operated in air,

so it is not necessary to designate them as air circuit breakers as this

understood．Medium and high—voltage breakers，on the other hand，u mediums

other than air in which to open the circuit and therefore must be designated as being

air, gas，and so on．

Apart from having different voltage and continuous current ratings．breakers

have widely different interrupting ratings，respon characteristics，and methods of

operation．The proper application of circuit breakers requires a good knowledge of all

the characteristics and options available for each type．

The simplest circuit—opening device is the manually operated knife switch．This

switch has the basic parts required of any circuit—opening device：a fixed contact, a

moving，an operating handle，and a ba—plate or flame．However as anyone who has

opened a knife switch under load has witnesd，there is a luminous discharge drawn

between the parating contacts of the switch．This discharge is called an arc，and it

consists of a stream of positive and negative ions. The current flowing in a circuit

cannot be instantaneously interrupted．As a result，the arc continues until the switch

contacts have parated far enough to finally extinguish the arc．

The arc can make the opening of the switch very unsafe and unreliable when

interrupting a circuit breaker must provide a safer and more reliable interrupting

action. The following are the means by witch low—voltage circuit breakers can be

made to safely interrupt large fault currents with a minimum of contact damage．

1．Fast speed of operation．The duration and verity of an arc depends in part on

the speed

with witch the contacts can be parated，therefore powerful spring are ud to rapidly

force the

contacts open．The springs are compresd (charged)during the closing

operation．The breaker contacts are then mechanically held clod and are relead by

a parate trip mechanism．An

operator can initiate the opening of the breaker but has no control over the speed with

which the

contacts parate．

2．U of arcing contacts．The arc burn can cau pitting，which eventually

affects the ability

of the contacts to carry the load current when clod．To offt this, two parallel ts

of contacts are ud for each pole of the breaker，a main current carrying t and an

auxiliary or arcing t．When the breaker is tripped open, the main contacts parate

first，transferring the current flow to the arcing contacts．The arcing contacts then

parate a split cond late，drawing the arc between them and leaving the main

contacts free of any arcing．This allows the surfaces of the main current carrying

contacts to be made of high—conductivity metal such as silver，the surfaces of the

arcing contacts are then made of a tougher alloy better able to withstand the effects of

arcing．

3．U of arc chutes Parallel plates enclod in the form of a chute are mounted

directly above the arcing contacts．As the arcing contacts parate, the resulting are

creates a strong magnetic field that forces the arc upward into the plates．The arc

stream is then broken into a ries of small arcs，which are quickly cooled，deionized，

and extinguished．The ionized gas created by the are stream must be deionized

before they are expelled from the arc chute；otherwi，condary arcing could occur

between the line side terminals of the breaker, which are still energized．

中文譯文三：

斷路器

在引入保險絲的幾年內,越來越多的的電力企業開始尋找一個可替代的保護

電氣電路的方法。他們想要一個裝置,不會因為它的操作而被破壞,可能只是恢復

供電,也可以用來作為一種電路轉換的手段。斷路器，作為一種機電設備，就是

這種發展的成果。斷路器被定義為這樣的一種裝置：可以通過非自動的方式閉合

或斷開電路，也可以在正確應用其評級并且自身不被破壞的情況下根據電路中的

過電流自動的斷開電路。

與其它設備類似,斷路器分為額定1 000伏特,少許被認為超過1000伏低。

壓斷路器也分為兩個不同的類別,塑殼和萬能式。然而,在過去的幾年中這兩個類

型之間的區別已經變得不那么明確，因為一種新型的微型斷路器是通常操作在空

氣的,所以不需要將它視為空氣斷路器。另一方面,中壓和高壓斷路器使用空氣外

的其他的介質斷開電路,因此必須指被整定為空氣、瓦斯等其他斷路器一樣。

與其它設備類似,斷路器分為額定1 000伏特,少許被認為超過1000伏低。

壓斷路器也分為兩個不同的類別,塑殼和萬能式。然而,在過去的幾年中這兩個類

型之間的區別已經變得不那么明確，因為一種新型的微型斷路器是通常操作在空

氣的,所以不需要將它視為空氣斷路器。另一方面,中壓和高壓斷路器使用空氣外

的其他的介質斷開電路,因此必須指被整定為空氣、瓦斯等其他斷路器一樣。除

了有不同的電壓和不間斷電流額定值，斷路器有廣泛不同的分斷能力、響應特性

和運行方式，正確的應用斷路器需要深入理解斷路器的特點并且對斷路器的設置

要通用。

電路中的電流不能在瞬間打斷。因此,電弧會持續存在直到開關觸頭分離的

足夠遠,直到最終熄滅電弧。最簡單的斷路設備是手動刀開關。這個開關有任何

短路設備都需要的基本組件:一個固定的觸頭,一個移動的觸頭,一個操作手柄和

一個冷卻基板。然而，如果在帶負載的情況下打開刀開關,在開關的分斷觸點之

間會有發光放電。這放電稱為電弧弧,它由大量的的正負離子組成。電路中的電

流不能在瞬間打斷。因此,電弧會持續存在直到開關觸頭分離的足夠遠,直到最終

熄滅電弧。

電弧會使開關的開斷變得很不安全,不可靠，因此開斷一個斷路器必須保證

一個更安全、更可靠的開斷動作。

以下就是低壓斷路器以最小的損失安全斷開故障電流的方法。

1.迅速操作。電弧的持續時間和嚴重程度在某種程度上取決于觸點斷開的速

度。因此我們用強大的彈簧來迅速迫使觸點斷開。在合閘操作時這些彈簧是被壓

縮的(帶電)。開關觸點由一個單獨的跳閘裝置來控制它的接觸和斷開。一個操作

員可以控制斷開斷路器但無法控制觸點斷開的速度。

2.使用滅弧裝置。電弧燃燒會導致點蝕,最終影響觸點帶負載電流運行的能

力。為了消除這種缺陷, 斷路器的每個極都用兩組相同的觸點,主要載流觸點和

一個輔助觸點或滅弧裝置。當斷路器跳閘斷開時，主觸點首先分開并且將當前電

流轉移到滅弧觸點。滅弧觸點然后在一瞬間斷開,吸引了他們之間的電弧而使主

觸點不受電弧影響。這就允許主觸點的表面可以用超導金屬來制作例如銀，滅弧

觸點的表面則是用可以很好滅弧的合金制作的。

3.使用滅弧隔板封。滅弧觸點上面直接安插著以斜槽形式排列的平行隔板,

在滅弧觸點分開時,會產生一個強磁場使得電弧向上到達隔板。弧流然后分解成

一系列的小弧線,迅速冷卻,去離子,最后熄滅。電離氣體流在被從滅弧隔板中趕

出之前必須背去離子化；否則,在斷路器的線路終端之間會發聲二次放電，而它

仍然是帶電的。