無(wú)功功率優(yōu)化研究開題報(bào)告葛祥

1、石河子大學(xué)畢業(yè)論文(設(shè)計(jì))開題報(bào)告課題名稱： 配電網(wǎng)無(wú)功功率優(yōu)化研究 學(xué)生姓名： 葛祥 學(xué) 號(hào)： 2010509017 學(xué) 院： 機(jī)械電氣工程學(xué)院 專業(yè)、年級(jí)： 10級(jí)電氣工程及其自動(dòng)化 指導(dǎo)教師： 王洪坤 職 稱： 講師 畢業(yè)論文(設(shè)計(jì))起止時(shí)間 2014-3-1至2014-6-1 一、課題的目的及意義無(wú)功功率補(bǔ)償優(yōu)化問題就是找出補(bǔ)償位置及容量的問題，它是一個(gè)在滿足約束條件下求目標(biāo)函數(shù)極值的復(fù)雜非線性問題。因目標(biāo)函數(shù)與約束條件的非線性、控制變量的離散性與連續(xù)性相混合等特點(diǎn)，其問題的關(guān)鍵集中在對(duì)非線性函數(shù)的處理、算法的收斂上和如何解決離散變量的問題。而配電網(wǎng)無(wú)功優(yōu)化是指合理配置無(wú)功補(bǔ)償設(shè)備，合

2、理安排運(yùn)行方式，優(yōu)化無(wú)功潮流分布，進(jìn)步無(wú)功治理水平，從而改善城市電網(wǎng)功率傳輸和電壓質(zhì)量，減少受端無(wú)功功率損耗，進(jìn)步功率因數(shù)，降低網(wǎng)絡(luò)損耗，進(jìn)步發(fā)、供電設(shè)備利用率，進(jìn)步無(wú)功補(bǔ)償設(shè)備運(yùn)行水平。無(wú)功補(bǔ)償一般根據(jù)分區(qū)分層就地平衡的原則，采用集中補(bǔ)償和分散補(bǔ)償相結(jié)合的方式，高壓配電網(wǎng)般在變電站集中補(bǔ)償，中壓配電網(wǎng)多采用分散補(bǔ)償方式。2、 國(guó)內(nèi)外研究現(xiàn)狀在無(wú)功優(yōu)化配置方面，聞內(nèi)外已經(jīng)形成了比較成熟和完善的算法早起最簡(jiǎn)單的無(wú)功功率補(bǔ)償算法是由Neagle和Samson提出來(lái)的，假設(shè)無(wú)功負(fù)荷沿線均勻分布，只考慮支路電流無(wú)功部分變化引起損耗減少，且忽略節(jié)點(diǎn)電壓變化而得到的2/3法則。但是該簡(jiǎn)單計(jì)算方法只對(duì)梳狀網(wǎng)

3、而非樹狀網(wǎng)，因此如何將樹狀網(wǎng)簡(jiǎn)化成梳狀網(wǎng)，將會(huì)是影響計(jì)算結(jié)果的關(guān)鍵所在。接著就是各種傳統(tǒng)的數(shù)學(xué)規(guī)劃法，如線性規(guī)劃法、非線性規(guī)劃法、混合整法、動(dòng)態(tài)規(guī)劃法等，及圍繞這些算法的一些該進(jìn)完善。其中較為引人注目的是最近幾年興起的一些人工智能方法，如遺傳算法、模擬退火法、模糊集合理論以及規(guī)劃和智能法相結(jié)合的功率矩法，但是我國(guó)在實(shí)施和運(yùn)行方面還有在一定的差距。在我國(guó)的城市配電網(wǎng)建設(shè)和運(yùn)行中，長(zhǎng)期存在著無(wú)功補(bǔ)償容量不足或分組不合理的問題，造成部分地區(qū)補(bǔ)償裝置投切不靈活，甚至無(wú)法投運(yùn)。由于無(wú)功缺乏統(tǒng)一的規(guī)劃和優(yōu)化，造成資金的極大浪費(fèi)。實(shí)行配電網(wǎng)無(wú)功優(yōu)化技術(shù)，有針對(duì)性地進(jìn)行無(wú)功補(bǔ)償，具有非常大的經(jīng)濟(jì)效益和社會(huì)效益

4、。目前，我國(guó)電力網(wǎng)平均線路功率損耗比國(guó)外發(fā)達(dá)國(guó)家高出24個(gè)百分點(diǎn)。就全國(guó)講，線路gesep全球節(jié)能環(huán)保網(wǎng)損耗約占據(jù)12%，其中主要是無(wú)功分量引起的損耗，若無(wú)功線損降低50%60%，一年便可節(jié)電500億kWh左右，相當(dāng)于半個(gè)三峽工程的發(fā)電量。這種不消耗一次能源，便可增大發(fā)電量的工程是絕好的綠色工程，且投資極小，見效快。三、研究?jī)?nèi)容及預(yù)期目標(biāo)研究?jī)?nèi)容：（1）學(xué)習(xí)配網(wǎng)無(wú)功功率優(yōu)化的工作過(guò)程。（2）利用粒子群算法計(jì)算解決配網(wǎng)無(wú)功功率優(yōu)化問題。（3）總結(jié)配網(wǎng)無(wú)功功率優(yōu)化設(shè)計(jì)，對(duì)理論結(jié)果與測(cè)試結(jié)果進(jìn)行分析。（4）根據(jù)配電網(wǎng)絡(luò)的要求，做配電網(wǎng)絡(luò)功率優(yōu)化設(shè)計(jì)。從而解決配電網(wǎng)絡(luò)無(wú)功功率耗費(fèi)過(guò)大的問題。預(yù)期目標(biāo)：

5、（1） 在無(wú)功功率優(yōu)化配置中加入了經(jīng)濟(jì)性的考慮，并且應(yīng)用經(jīng)濟(jì)學(xué)原理講投資析算成等年值進(jìn)行計(jì)算，使優(yōu)化工作更符合實(shí)際應(yīng)用的需要。（2） 應(yīng)用粒子群算法參與補(bǔ)償點(diǎn)的選取優(yōu)化，并根據(jù)配網(wǎng)的實(shí)際情況將粒子群算法改為更適合節(jié)點(diǎn)選擇的二進(jìn)制算法。因?yàn)楣?jié)點(diǎn)的選擇只有補(bǔ)償和被補(bǔ)償兩種狀態(tài)，二進(jìn)制的位數(shù)1和0能很好地代表補(bǔ)償和不補(bǔ)償兩種狀態(tài)，這種該進(jìn)使得粒子群算法更適用于配網(wǎng)網(wǎng)絡(luò)的補(bǔ)償點(diǎn)優(yōu)化。（3）綜合三種負(fù)荷狀態(tài)進(jìn)行網(wǎng)損的計(jì)算，將系統(tǒng)分為最大負(fù)荷、一般負(fù)荷、最小負(fù)荷三種狀態(tài)，并且根據(jù)實(shí)際情況將其運(yùn)行時(shí)間比率設(shè)為0.25、0.5、0.25.從而避免了只考慮單一負(fù)荷的片面性，同時(shí)又使網(wǎng)損的計(jì)算能夠更好地符合實(shí)際情

6、況，達(dá)到促進(jìn)優(yōu)化精確性的效果。（4）應(yīng)用本文所提出的粒子群算法對(duì)某12節(jié)點(diǎn)配網(wǎng)及某28點(diǎn)節(jié)點(diǎn)配電網(wǎng)絡(luò)進(jìn)行無(wú)功補(bǔ)償優(yōu)化設(shè)置，充分證明該方法的合理性和有效性。4、 工作方案及進(jìn)度計(jì)劃階 段日 期 安 排 開題報(bào)告 2014年2月20日2014年3月1日 查詢文獻(xiàn)，進(jìn)行整理與閱讀 2014年3月2日2014年3月15日 完成課程設(shè)計(jì)技術(shù)方案 2014年3月16日2014年3月20日 完成各功能設(shè)計(jì) 2014年3月21日2014年4月22日 整理論文完成論文初稿 2014年4月23日2014年5月1日 論文定稿 2014年5月2日2014年5月25日五、參考文獻(xiàn)1張伯明、陳壽孫，高等電力網(wǎng)絡(luò)分析，清華

7、大學(xué)出版社，19992靳龍章、丁毓山，電網(wǎng)無(wú)功補(bǔ)償實(shí)用技術(shù)，電力自動(dòng)化設(shè)備，20013.李劍虹.顧紹柱.盧志剛.韓彥玲 配電網(wǎng)運(yùn)行經(jīng)濟(jì)性評(píng)價(jià)期刊論文 - 華北電力技術(shù) 2008(2)4楊維，粒子群算法綜述，中國(guó)工程科學(xué)，2004 5王成山，張義基于Benders分解和內(nèi)點(diǎn)法的無(wú)功優(yōu)化規(guī)劃J電力系統(tǒng)及其自動(dòng)化學(xué)報(bào)， 2003 6李林川，王建勇，陳禮儀，等電力系統(tǒng)無(wú)功補(bǔ)償優(yōu)化規(guī)劃J中國(guó)電機(jī)工程學(xué)報(bào)，1999 7許文超， 郭偉 電力系統(tǒng)無(wú)功優(yōu)化的模型及算法綜述J 電力系統(tǒng)及其自動(dòng)化學(xué)報(bào)，2003，(15)：100104指導(dǎo)教師審閱意見： 指導(dǎo)教師（簽字）： 年 月 日備注： 文獻(xiàn)綜述緒論： 改善工業(yè)

8、企業(yè)用電的功率因數(shù)是提高用電效率、節(jié)約電能的重要手段。本文通過(guò)理論分析和應(yīng)用實(shí)例說(shuō)明了工業(yè)企業(yè)無(wú)功補(bǔ)償?shù)囊饬x和作用，并針對(duì)目前工業(yè)企業(yè)供用電系統(tǒng)存在的問題，提出了改進(jìn)意見和措施。1 引言在工業(yè)企業(yè)中，絕大多數(shù)的用電設(shè)備屬于感性負(fù)荷，這些設(shè)備在運(yùn)行中要吸收大量的無(wú)功功率。無(wú)功功率的增加使供電系統(tǒng)的功率因數(shù)降低，從而出現(xiàn)系統(tǒng)電壓下降、電氣設(shè)備得不到充分利用、增加線路損耗以及降低供電設(shè)備的供電能力等情況。因而就地進(jìn)行無(wú)功補(bǔ)償、提高功率因數(shù)對(duì)降損節(jié)能有著極為重要的意義。2 補(bǔ)償方式的選擇無(wú)功補(bǔ)償分為集中補(bǔ)償、分散補(bǔ)償和就地補(bǔ)償三種。集中補(bǔ)償，即在高、低壓配電所內(nèi)設(shè)置若干組電容器，電容器接在配電母線上，

9、補(bǔ)償該配電所供電范圍內(nèi)的無(wú)功功率，并使總功率因數(shù)達(dá)到規(guī)定值以上。這種補(bǔ)償方式只能補(bǔ)償高、低壓母線之前線路上的無(wú)功功率，它們相當(dāng)于把無(wú)功功率源移到用電企業(yè)的配電所，使用戶對(duì)供電系統(tǒng)要求的無(wú)功功率有所減少，達(dá)到供電部門所要求的功率因數(shù)。而它們對(duì)配電母線以下的企業(yè)內(nèi)部的變壓器和線路的無(wú)功功率不能起到補(bǔ)償作用，仍有大量的無(wú)功功率在企業(yè)內(nèi)部線路上流動(dòng)并產(chǎn)生損耗。分散補(bǔ)償是將電容器組分別安裝在各個(gè)車間的配電盤處，這種安裝方式可以使配電變壓器以及變電所至車間的線路都可以由于無(wú)功負(fù)荷的減少而獲得補(bǔ)償效果。就地補(bǔ)償是把無(wú)功補(bǔ)償器直接接在異步電動(dòng)機(jī)旁或進(jìn)線端子上。集中補(bǔ)償方式所用電容器組的容量較分組補(bǔ)償或就地補(bǔ)償

10、要小，它的利用率則更高，缺點(diǎn)是對(duì)變、配電所各饋線并未得到補(bǔ)償，僅減輕了電網(wǎng)的無(wú)功負(fù)荷。分散補(bǔ)償方式中的電容器組的利用率比就地補(bǔ)償高，因此總需要量較就地補(bǔ)償要小，是一種經(jīng)濟(jì)合理的補(bǔ)償方式。無(wú)功補(bǔ)償應(yīng)遵循“全面規(guī)劃，合理布局，分級(jí)補(bǔ)償，就地平衡;集中補(bǔ)償與分散補(bǔ)償相結(jié)合，以分散補(bǔ)償為主；高壓補(bǔ)償與低壓補(bǔ)償相結(jié)合，以低壓補(bǔ)償為主；調(diào)壓與降損相結(jié)合，以降損為主”的原則。3 補(bǔ)償容量的確定在電力網(wǎng)中無(wú)功功率的消耗是很大的，大約50 %的無(wú)功功率消耗在輸、變、設(shè)備上，50 %消耗在電力用戶上。為了減少無(wú)功功率消耗，就必須減少無(wú)功功率在電網(wǎng)里的流動(dòng)。最好的辦法從用戶開始增加無(wú)功補(bǔ)償，提高用戶負(fù)荷的功率因數(shù)，

11、這樣可以減少發(fā)電機(jī)無(wú)功出力和減少輸、變、配電設(shè)備中的無(wú)功電力消耗，從而達(dá)到降低損耗的目的。補(bǔ)償?shù)臒o(wú)功功率容量為式中最大負(fù)荷日平均有功功率；未裝設(shè)補(bǔ)償裝置前的功率因數(shù)實(shí)測(cè)值；裝設(shè)補(bǔ)償裝置后所達(dá)到的功率因數(shù)值。4 無(wú)功補(bǔ)償裝置的作用可以根據(jù)負(fù)荷變化情況決定采用靜態(tài)還是動(dòng)態(tài)補(bǔ)償方式。當(dāng)負(fù)荷變化較為平穩(wěn)時(shí)，應(yīng)采用靜態(tài)補(bǔ)償方式，這不僅能較好地降低線路損耗，而且投資少;當(dāng)負(fù)荷變化較大時(shí)，應(yīng)采用動(dòng)態(tài)補(bǔ)償方式，穩(wěn)定電壓。4.1 降低線損設(shè)在某一額定電壓下，有功功率恒定不變，由于功率因數(shù)變化，其線路損耗變化率P %為從表4.1中可以看出提高功率因數(shù)對(duì)于降低電能損耗，提高經(jīng)濟(jì)效益具有十分重要的作用。表4.1功率因

12、數(shù)與有功損耗百分率的對(duì)應(yīng)數(shù)據(jù)若在恒定有功功率條件下，原有的功率因數(shù)為0.60，補(bǔ)償后的功率因數(shù)為1，0時(shí)，其線損率降低%為64 %。采用動(dòng)態(tài)補(bǔ)償裝置，將電力電容器分組跟蹤補(bǔ)償，則可由原來(lái)不同的功率因數(shù)穩(wěn)定在所規(guī)定的功率因數(shù)范圍內(nèi)，達(dá)到充分補(bǔ)償?shù)哪康摹?.2 線路、變壓器的增容線路、變壓器的增容量S 為加設(shè)補(bǔ)償裝置后，可提高功率因數(shù)，對(duì)企業(yè)的直接功率因數(shù)經(jīng)濟(jì)效益是明顯的。因?yàn)閲?guó)家電價(jià)制度中，從合理利用能源出發(fā)，依據(jù)企業(yè)的功率因數(shù)值來(lái)調(diào)整電價(jià)高低。這種補(bǔ)償裝置對(duì)企業(yè)和整個(gè)電力系統(tǒng)的經(jīng)濟(jì)運(yùn)行都有著重大的經(jīng)濟(jì)效。4.3 改善電壓質(zhì)量改善電壓質(zhì)量是指裝設(shè)動(dòng)態(tài)無(wú)功補(bǔ)償裝置前后，作用在補(bǔ)償?shù)攸c(diǎn)的線路電壓稍有

13、提高。式中未裝設(shè)補(bǔ)償裝置前角的正切；裝設(shè)補(bǔ)償裝置后角的正切；R 、x 線路的電阻、電抗。5 工業(yè)企業(yè)供用電系統(tǒng)存在的問題與解決措施圖1為某重型機(jī)床廠供電系統(tǒng)示意圖。目前，該廠變壓器總?cè)萘繛?7660kVA ，共有20臺(tái)變壓器(1 # 20 # 變壓器) ，每臺(tái)變壓器的容量范圍為501250 kVA ，變比為10kV/ 014kV。變壓器低壓側(cè)負(fù)載主要為電動(dòng)機(jī)，如圖中M1 、M2 Mn 所示。一般情況變壓器負(fù)載率基本上維持在28 %29 %之間，最大負(fù)載時(shí)為7000kW。5.1 采用高、低壓相結(jié)合的補(bǔ)償方式取代高壓集中補(bǔ)償從圖中可以看到該廠供電網(wǎng)絡(luò)的功率因數(shù)補(bǔ)償是高壓集中補(bǔ)償，即只在變電所10k

14、V 的高壓母線上接電容器組，而低壓卻沒有采取任何補(bǔ)償措施。這種固定電容器補(bǔ)償?shù)姆椒〞?huì)出現(xiàn)過(guò)補(bǔ)償或欠補(bǔ)償?shù)那闆r，并且對(duì)二次母線以下的供電線路的功率因數(shù)補(bǔ)償不起作用。由于功率因數(shù)低而造成的線路損失和變電設(shè)備的損失是很大的，所以補(bǔ)償時(shí)要盡量做到分級(jí)，靠近負(fù)載處安裝電容器。因而提出高壓側(cè)集中補(bǔ)償和低壓側(cè)分散補(bǔ)償相結(jié)合的補(bǔ)償方式。圖5.1某重型機(jī)床廠供電系統(tǒng)示意圖5.2 改變供電方式，盡可能避免“大馬拉小車”的現(xiàn)象在設(shè)備選型時(shí)，要考慮留有一定的容量，防止重載時(shí)損壞設(shè)備，這樣大部分時(shí)間都造成設(shè)備欠載和嚴(yán)重欠載形成“大馬拉小車”運(yùn)行。由于該廠變壓器的負(fù)載率基本上在28 %29 %之間，說(shuō)明變壓器的裝機(jī)容量過(guò)

15、大，變壓器容量不能充分利用，既浪費(fèi)了設(shè)備投資又增加了電能損耗?？梢酝ㄟ^(guò)合理選擇變壓器的容量以及減少或限制用電設(shè)備輕載或空載的時(shí)間來(lái)防止“大馬拉小車”現(xiàn)象。5.3 避免設(shè)備的空載運(yùn)行目前，該廠某些設(shè)備的空載運(yùn)行嚴(yán)重。在提高功率因數(shù)時(shí)，首先應(yīng)考慮使設(shè)備合理運(yùn)行，提高耗電設(shè)備本身的功率因數(shù)。該廠主要負(fù)荷是交流電動(dòng)機(jī)，其功率因數(shù)隨它的負(fù)載而改變，電動(dòng)機(jī)在空轉(zhuǎn)時(shí)，功率因數(shù)約在0.10.3 之間，額定負(fù)載時(shí)在0.80.85 之間，因而應(yīng)使電動(dòng)機(jī)接近額定負(fù)荷狀態(tài)下運(yùn)行。要把電動(dòng)機(jī)功率因數(shù)提高，最簡(jiǎn)單的辦法是用電容器和電動(dòng)機(jī)并聯(lián)，所以避免設(shè)備的空載運(yùn)行是提高設(shè)備功率因數(shù)的重要途徑。5.4 建議完善配電設(shè)備或?qū)?/p>

16、其進(jìn)行重新改造在現(xiàn)場(chǎng)測(cè)量數(shù)據(jù)的過(guò)程中，我們發(fā)現(xiàn)很多配電設(shè)備老化現(xiàn)象嚴(yán)重，沒有電流表、電壓表或者讀數(shù)不準(zhǔn)確，如鏜床車間的配電房?jī)?nèi)完全沒有電流表和電壓表。6 經(jīng)濟(jì)效益分析以該廠供電系統(tǒng)中的2 # 變壓器為例，在低壓側(cè)加裝電容器，使該廠采取高壓側(cè)集中補(bǔ)償和低壓側(cè)分散補(bǔ)償相結(jié)合的補(bǔ)償方式，如圖6.1 。圖中2 # 變壓器容量為800kVA ，型號(hào)為S9 - 800/ 10 ，額定銅損耗為 = 715kW ，輸電線路型號(hào)為YJV22 。取電價(jià)為0.55元/ kW.h 。將功率因數(shù)由補(bǔ)償前的0.59提高到補(bǔ)償后的0.98 ，表6.1是利用測(cè)量?jī)x器在現(xiàn)場(chǎng)測(cè)得的變壓器運(yùn)行時(shí)二次側(cè)數(shù)據(jù)，現(xiàn)通過(guò)計(jì)算分析無(wú)功補(bǔ)償降

17、損節(jié)能效益。圖6.1鑄造車間供電圖表6.1 變壓器運(yùn)行時(shí)二次側(cè)數(shù)據(jù)表6.1 高壓供電線路節(jié)電全年節(jié)約電能W =h式中增加的線路電功率，h 年運(yùn)行小時(shí)數(shù)，取5000h 。經(jīng)計(jì)算全年節(jié)約電能162217kW.h ，一年內(nèi)降低的電能損耗費(fèi)8192萬(wàn)元。6.2 變壓器節(jié)電變壓器的損耗主要有鐵損和銅損。提高變壓器二次側(cè)的功率因數(shù)，可使總的負(fù)荷電流減少，從而減少銅損。全年節(jié)約變壓器銅損耗電能h 式中補(bǔ)償前變壓器實(shí)際運(yùn)行時(shí)的銅損耗電功率PCu2 補(bǔ)償后變壓器的銅損耗電功率經(jīng)計(jì)算全年節(jié)約電能3150kW.h ，一年內(nèi)節(jié)約變壓器銅損耗電費(fèi)173518元。6.3 功率因數(shù)調(diào)整電費(fèi)用戶一年內(nèi)減少因功率因數(shù)偏低多支出

18、的罰金:800 0. 5895000 0.55 17.22 %(增收率) =22131萬(wàn)元補(bǔ)償后用戶一年內(nèi)得到的功率因數(shù)獎(jiǎng)金:800 0. 589 5000 0.55 2.7 %(減收率) =315萬(wàn)元兩項(xiàng)總計(jì)為25181萬(wàn)元由上述計(jì)算可知一年內(nèi)合計(jì)增加純收入34173萬(wàn)元，根據(jù)補(bǔ)償容量需設(shè)備投資2715萬(wàn)元，9個(gè)月就能收回投資。這說(shuō)明針對(duì)該廠鑄造車間的具體情況在變壓器二次側(cè)采用分散補(bǔ)償?shù)姆绞竭M(jìn)行無(wú)功補(bǔ)償是可行的，并且能取得長(zhǎng)期且明顯的經(jīng)濟(jì)效果。 Industrial enterprises of reactive power compensation From:Power System An

19、alysis and DesignAbstract The improvement of industrial enterprises is to improve the power factor of electric power efficiency， an important means of saving energy. In this paper， theoretical analysis and application examples of the industrial enterprises， the significance of reactive power compens

20、ation and the role and view of the current power system， industrial enterprises， the problems for the proposed improvements and measures. Introduction In industrial enterprises， the vast majority of electrical equipment belongs to perceptual load， these devices in operation to absorb a large number

21、of reactive power. An increase in reactive power supply system power factor to lower system voltage drop to occur， electrical equipment not fully utilized， increasing line losses and lower-powered equipment， power supply capacity and so on. In situ reactive power compensation and thus improve the po

22、wer factor of the Energy Conservation has extremely important significance. The choice of method of compensation Compensation for reactive power compensation is divided into centralized and decentralized compensation for three kinds of compensation and in situ. Focus on compensation， that is， high a

23、nd low voltage power distribution set up by several groups within the capacitor， capacitor connected to the power distribution bus， the compensation for the distribution of power within the reactive power， and to reach the required value of the total power factor above. This method of compensation c

24、an compensate for high and low voltage bus routes prior to the reactive power， which is equivalent to the reactive power source to move the electricity distribution companies， allowing users to power the system requirements for reactive power has been reduction in the electricity sector to achieve t

25、he required power factor. And their distribution within the enterprise bus following the line of transformer and reactive power compensation can not play a role， there is still a large number of reactive power line flows within the enterprise and generate losses. Dispersion compensation is the capac

26、itors were installed at various workshops at the switchboard， which will enable installation of distribution transformer and the substation to the plant lines can be due to a decrease in reactive load compensation effect. Local compensation is the reactive power compensation device directly connecte

27、d to the induction motor terminals on the side or into the line. Focus on compensation methods used in the capacity of capacitor compensation or in-place than the grouping of compensation should be small， its utilization rate is even higher disadvantage is the change in distribution has not been com

28、pensated by the feeders， only lightened the load reactive power grid. Dispersion compensation in the way the utilization of capacitor compensation than the in situ high， so the total requirement of compensation is smaller than the spot is an economical and reasonable remedy. Reactive power compensat

29、ion should follow the overall planning， rational distribution， classification of compensation， in-place balance; focus on compensation and dispersion compensation combine to spread-based compensation; high compensation and low voltage compensation combined with low-pressure-based compensation; Regul

30、ator combined with lower losses， down are the main loss principle 1. Compensation capacity to determine In the power grid in the reactive power consumption is a big， about 50% of the reactive power consumed in transmission， transformation and the device， 50% of the consumed electricity users. In ord

31、er to reduce reactive power consumption， it is necessary to reduce the reactive power in the grid where flow. The best way to start from the user to increase reactive power compensation， improve user load power factor， so that Generator reactive power can be reduced and the reduction of transmission

32、， transformation and distribution equipment in the reactive power consumption， so as to achieve the purpose of reducing wear and tear 2. Compensation for reactive power capacity of Qc for Load changes can be decided according to the static or dynamic compensation mode. When the load change is relati

33、vely stable， we should use the static method of compensation， which can not only reduce the line losses， and investment; when the load change is large， dynamic compensation method should be used， stable voltage 3. Reduce line lossesIs located at a rated voltage， active power is constant， due to powe

34、r factor changes， the line loss rate of change P% for the As can be seen from Table 1 to improve the power factor in lowering power consumption， improving economic efficiency plays an important role. Table 1 Power factor and power loss percentage of the corresponding data If a constant active power

35、condition， the original power factor cos1 of 0.59， compensated power factor cos2 of 0.98， its line loss rate reduction % to 64%. Dynamic compensation device， Group to track the power capacitor compensation， power factor can be different from the stability provided in the context of the power factor

36、to achieve adequate compensation purposes. Lines， transformer capacity increase Lines， transformer capacity increased S for the Additional compensation device， may improve the power factor， power factor on the business of direct economic benefit is obvious. Because the state electricity system， star

37、ting from the rational use of energy， according to the power company to adjust the price due to high and low values. The compensation device for enterprise and the entire power system economic operation all have significant economic effects . To improve the voltage quality To improve the voltage qua

38、lity is the dynamic reactive power compensation equipment installed around the role of place in the line voltage compensation has increased slightly . Where tg1 - compensation device is not installed before the 1 angle tangent; tg2 - compensation equipment installed after the 2 angle tangent; R， x -

39、 line resistance， reactance. Industrial enterprises for the power system problems and solution Fig 1 for a diagram of power supply systems for heavy machine tool plant. At present， the total capacity of the plant transformer 17660kVA， a total of 20 transformers (1 # 20， # transformers)， each transfo

40、rmer capacity range of 50 1250 kVA， changing the ratio of 10kV / 014kV. Transformer low voltage side of the load is mainly motor， shown in the M1， M2 Mn shown. In general the rate of transformer load is basically maintained at 28% 29%， and the maximum load of 7000kW. High and low voltage compensatio

41、n to replace a combination of high concentration of compensation From the figure we can see the plant supply network focused on high-voltage power factor compensation is compensation that is only in the high-voltage busbar 10kV substation capacitor banks on the pick， while the low pressure has not t

42、aken any compensation measures. The fixed capacitor compensation method there have been compensation or due compensation， and right below the second power supply bus power factor compensation circuit does not work. As the low power factor caused by the line losses and transformer equipment is a big

43、loss， so compensation as far as possible when grading， installation of capacitors near the load. Therefore proposed that the high side to focus compensation and dispersion compensation for low-voltage side of a combination of method of compensation . Figure 1 Power Supply System of a Heavy Machine T

44、ool Plant diagramTo change the power supply as much as possible to avoid the big horse-drawn cart phenomenon In making our selection， we should consider leaving a certain margin， to prevent heavy damage to equipment when， so most of the time caused by equipment， and severe underrun underrun the form

45、ation of the big horse-drawn cart Run. As the plant load factor of the transformer is basically 28% 29%， and shows the transformer capacity is too large， transformer capacity can not be fully utilized， not only a waste of investment in equipment has increased the power loss. Rational choice by the t

46、ransformer capacity and electrical equipment to reduce or limit the light-load or no load time to prevent the big horse-drawn cart phenomenon. To avoid the no-load operation of equipment At present， the plant is running a serious load of some equipment. Improving the power factor， the first consider

47、ation should be given a reasonable run the equipment to improve power factor of power the device itself. The plant main load is AC motor， its power factor load with it change， motor idling， the power factor of about 0.1 0.3 between the rated load at 0.8 0.85 between the motor and thus should be made

48、 near the rated load state run. We should improve the motor power factor， the simplest way is to use capacitors and electric motors in parallel， so to avoid the no-load operation device is to improve the power factor equipment， an important way. Economic Benefit Analysis To the factory power supply

49、system in two # transformers， for example， installation of capacitors in the low voltage side， so that high-pressure side of the plant to focus on compensation and dispersion compensation combination of low-voltage side of a compensation formula， shown in Figure 2. Graph 2 #transformer capacity of 8

50、00kVA， model S9 - 800 / 10， rated copper loss for the 715kW， transmission line model YJV22. Get price of 0.55 yuan / kWh. The power factor by the compensation prior to 0.59 to compensate for post-0.98， Table 2 is the use of measuring instruments measured in the field of transformer secondary side ru

51、n-time data are analyzed by calculating the loss of reactive power compensation reduced energy efficiency. Figure 2 foundry supply diagram Table 2 transformer secondary-side run-time data tableThe energy-saving high-voltage power lines Throughout the year to save electricity W = hWherel- the increas

52、e in electric power lines，The number of annual operating hours， whichever 5000h. The calculation of annual energy savings 162217kW.h， within one year to reduce electricity consumption costs 81.92 million yuan. Transformer-saving The loss of main transformer iron loss and copper loss. Transformer sec

53、ondary side to improve the power factor， can reduce the total load current， thereby reducing the copper loss. Transformer copper loss of the year to save energy W = (PCu1 - PCu2) h where PCu1 - compensation for the actual run-time before the transformer copper loss of electric power， PCu2 - compensa

54、ted transformer copper loss of electric power， The calculation of annual energy savings 3150kWh， within a year to save electricity transformer copper loss of 173，518 yuan. Power Factor Adjustment tariff Users within a year to reduce spending more than the low power factor penalty: 800 0. 589 5000 0.

55、55 17.22% (increase rate) = 221.31 million yuan of compensation within one year after the users get the power factor bonus: 800 0. 589 5000 0.55 2.7% (reduced rate) 3.15 million total of 251.81 million yuan from the two above calculations we can see an overall increase within one year of net income

56、341.73 million yuan， according to the capacity required to compensate for equipment investment 27.15 million yuan， 9 months will be able to recover their investments. This shows that the plant foundry for the specific circumstances of the transformer secondary side compensation for use of decentralized approach to reactive power compensation is feasible and can achie