【正文】 otor is revolutions per minutes (r/min), this works out to cycles per minute, and the frequency of the induced . is： For f=50Hz, the rotor of a generator with one pair of poles should run at 3000r/ with two polepairs, at 1500r/min. With speeds like this, rotors are usually fabricated with nonsalient piles for greater mechanical strength.Highfrequency generators operating at 800 to 8000Hz are all of special designs. Their uses are in the heattreatment and inductionheating field. Still higher frequencies are generated by valve and semiconductor oscillators.Sinusoidal CurrentThe instantaneous value of a sinusoidal current is given bywhere is the peak value or amplitude of the current, and is the phase of the current. The quantity is the initial phase of the current (for t=0) and is termed the epoch angle. The phase of a current continuously increases with time. When it has increase by , the whole cycle of changes is repeated exactly all over again. Therefore, s peaking of the phase of a current, it is customary to drop the integer and to consider the phase within or between zero and .The above change of phase by occurs during the period T. therefore, the rate of change of the phase is given by . It is symbolized by the Greek letter (omega) and is called the pulsatance. Noting that , we may writeThe above expression, relating and ,has been responsible for the fact that the pulstance is also termed the angular velocity or frequency. It is expressed in radians per second. Thus, for , . Introduce in Eq.() we obtainSinusoidal current of the same frequency, but differing in amplitude and epoch angles, are shown in . their instantaneous values are The time or the product ,proportional to time, is laid off as abscissa. The epoch angle is always measured between the origin of coordinates, which corresponds to the reference time t=0, and the instant when a given sinusoidal just passes through zero(from negative to positive values). For 0, the start(or zero point) of the sinusoid is shifted to the left, and for 0 it is shifted to the right of the origin of coordinates.Alternatively, the instantaneous value of a sinusoidal current may be represented by a cosinusoidal function of the form)Where .When two or more sinusoidal function differ in time phase as reckoned from similar points, they are said to be shifted or displaced in phase with respect to one another. This phase shift, or the phase displacement, is measured between their respective zeros, and obviously is the difference in epoch angles. Referring to , , and the current is said to lead the current in phase by , or, which is the same, the current lags in phase behind the current by . Two sinusoidal functions of the same frequency are said to be in phase if they have same epoch angle, and are said to be in antiphase when their phase displacement is . Finally, they are said to be in quadrature if their difference is .附錄B 外文翻譯——譯文部分交流電交流電在電路中是一個(gè)隨時(shí)間變化的值。 hence the term a harmonic or a sinusoidal current. The preference for sinusoidal currents is explained modulated by the signal in amplitude, frequency or phase. Periodic nonsinusoidal current may likewise be treated as posed of sinusoidal current at a variety of frequencies occurring simultaneously. This is why thorough of sinusoidalcurrent circuits is of primary importance.The GeneratorAn generator consists of a stationary part, the stator, and a revolving part, the rotor. As a rule the rotor carries magnetic poles with coils around them. These are the filed coils of the generator ,because they establish a magnetic filed in the machine. They are energized with direct current through slip rings and brushes. The slots of the stator staked up from electricalsheet steel punchings receive the coils of the stator winding. The stator coils are connected in series, as shown by the fully and dotted lines in the drawing.The . induced in a stator conductor is given bywhere —magnetic induction of the field moving relative to the conductor。最后我要感謝所有幫助過(guò)支持過(guò)我的老師和同學(xué)。相信，它將使我們受益終身的?？傊敬卧O(shè)計(jì)，基本達(dá)到了鍛煉我們的目的。但如果電源質(zhì)量相同，那就要看在供配電的設(shè)計(jì)中，是不是合理了。不管怎樣，設(shè)計(jì)效果基本達(dá)到了本實(shí)際工程的需求和老師的要求。當(dāng)然要把這個(gè)設(shè)計(jì)用于現(xiàn)實(shí)施工中，可行性還是有一定欠缺的。在整個(gè)設(shè)計(jì)的過(guò)程中，我也時(shí)刻本著不懂就問(wèn)的原則，虛心的向?qū)W校的老高工學(xué)習(xí)請(qǐng)教。比如象在我們這個(gè)題目中，在選擇電纜的時(shí)候，我一開(kāi)始不知道，就隨便選了油浸式的，但聽(tīng)老師講解后，才知道在現(xiàn)實(shí)中一般不用這樣的電力電纜，而是用塑料電纜，油浸式的通常應(yīng)用在環(huán)境比較惡劣的場(chǎng)所。由于我們做的是實(shí)際工程，不可避免的要牽扯到很多現(xiàn)實(shí)生活中的東西。在整個(gè)的畢業(yè)設(shè)計(jì)過(guò)程中，我們把供配電工程又好好的復(fù)習(xí)了一遍，可以說(shuō)從頭到尾的又在我們的腦海中消化了一遍。最好能把這些老式柴油機(jī)處理掉，購(gòu)買進(jìn)新型節(jié)能，低耗，低污染的奔馳等。(2) 柴油發(fā)電機(jī)房設(shè)置在高壓配電房處，由于這里是生活區(qū)，相應(yīng)的噪聲污染和油污染會(huì)很大。走地下直埋的話，由于地下道處是一個(gè)低地，經(jīng)常有水滲透，線纜易受到腐蝕；如果走架空線，又很影響城市美觀。(5) 配電房的設(shè)置，便于了集中統(tǒng)一的管理。(3) 實(shí)現(xiàn)了自備應(yīng)急電源的高壓聯(lián)絡(luò)，直接有生活區(qū)1變，升壓為10KV后通過(guò)高壓配電線路送達(dá)各個(gè)變電所，設(shè)置集中，便于管理。 方案小結(jié) 方案評(píng)價(jià)(1) 高壓總配位于外來(lái)架空線路高壓入校處，進(jìn)線方便。前已有論述。相反，當(dāng)長(zhǎng)時(shí)間工作在輕載狀態(tài)下時(shí)（30%以下）的變壓器，應(yīng)更換小容量的變壓器，以減少電能損耗。當(dāng)一臺(tái)變壓器長(zhǎng)時(shí)間工作在輕載或過(guò)載，都會(huì)使效率下降，損耗增加。前已述及。 變配電裝置的節(jié)能為了使變壓器經(jīng)濟(jì)運(yùn)行，一般情況下，從以下幾個(gè)方面采取措施降低功率損耗。(2) 采用高效燈具在選擇燈具，一般不宜選用效率低于70%的燈具，采用熒光燈照明時(shí)應(yīng)選用高效熒光燈具及低能耗的電子鎮(zhèn)流器。任何一所高校都是一個(gè)大宗電力用戶。目前，全國(guó)照明用電約占發(fā)電量的8%~10%，總用電量的10%，%，所以開(kāi)展照明節(jié)能對(duì)于民用建筑的經(jīng)濟(jì)效益有著重要的意義，常用的照明節(jié)能措施有：、(1) 采用高效光源目前我國(guó)大量采用的幾種光源從節(jié)能效果的好壞來(lái)分為：高壓鈉燈，熒光燈，金屬鹵化物燈，汞燈，鹵鎢燈，白熾燈。這樣由于這些設(shè)備通常技術(shù)先進(jìn)，科技含量高，故初期投資雖高，但從長(zhǎng)期運(yùn)行來(lái)看，將節(jié)約大量的能源，也是一個(gè)節(jié)省電費(fèi)的好方法。 節(jié)能建議 電容補(bǔ)償前已述及的電容補(bǔ)償節(jié)能（及減少有色金屬耗量）在次不再贅述。工作原理和技術(shù)特性在此不做詳細(xì)介紹。UPS通常由整流器和充電器，儲(chǔ)能裝置，逆變裝置，開(kāi)關(guān)等組成。 UPS電源對(duì)某些不允許停電的（哪怕是1~2秒鐘）場(chǎng)所應(yīng)設(shè)置UPS電源。那么現(xiàn)在就有三電源，進(jìn)一步增強(qiáng)了我校的供電可靠性。但是由于我校的歷史原因，遺留下一些個(gè)柴油發(fā)電機(jī)，年代比較久遠(yuǎn)，有點(diǎn)老態(tài)龍鐘的感覺(jué)——似雞肋，食之無(wú)味，棄之可惜。 分時(shí)區(qū)別供電在有明顯時(shí)間區(qū)段用電負(fù)荷的變電所，可通過(guò)調(diào)節(jié)變壓器投入的臺(tái)數(shù)來(lái)適時(shí)調(diào)整供給量，甚至當(dāng)負(fù)荷相當(dāng)?shù)偷臅r(shí)候通過(guò)高壓配電房中的斷路器來(lái)切斷整個(gè)區(qū)的供電，而有鄰近的低壓聯(lián)絡(luò)線供給電能——主要時(shí)段是晚上11：30到早上6：00，和寒暑假期間。通常由進(jìn)線到個(gè)配線柜通過(guò)10KV電力電纜送到各區(qū)域變電所，降壓為380/220V后再通過(guò)低壓電力電纜送達(dá)各負(fù)荷點(diǎn)。但僅在實(shí)習(xí)工廠母線段上進(jìn)行電容補(bǔ)償，容量按全區(qū)負(fù)荷配制。這樣做能保證至少全部二級(jí)負(fù)荷和部分三級(jí)負(fù)荷的用電需求。 各變電所內(nèi)部設(shè)置給排水區(qū)，生活2區(qū)，研究生院區(qū)設(shè)置無(wú)特殊要求，采用單母線即可。最好能建成獨(dú)立式的變電所，具體位置建議設(shè)在教工住宅4棟之間的馬鞍山腳下。 低壓聯(lián)絡(luò)線在鄰近的變區(qū)設(shè)置低壓母線聯(lián)絡(luò)線，形成準(zhǔn)網(wǎng)式供電。當(dāng)控制回路設(shè)計(jì)的合理時(shí)，還可以實(shí)現(xiàn)自動(dòng)投切，停電后恢復(fù)期較短。各方案比較列表示下 項(xiàng)目方案號(hào)電源質(zhì)量供電可靠性建設(shè)費(fèi)用運(yùn)行維護(hù)費(fèi)用土建施工量靈活與否交通運(yùn)輸條件方案1相同高低省少是相當(dāng)方案2一般較高耗多一般方案3高高耗多是方案4一般高耗多一般 方案定案綜合比較以上各個(gè)方案,決定采用方案1,但需做些適當(dāng)?shù)难a(bǔ)充和改進(jìn)說(shuō)明 配電母線設(shè)置