功(gong)(gong)率因數(shu)(shu)是針對不同的負載說的，在(zai)之(zhi)前的直流(liu)電(dian)時(shi)代，是沒有功(gong)(gong)率因數(shu)(shu)這一說的，那時(shi)候功(gong)(gong)率因數(shu)(shu)都是1。后(hou)來特斯拉將我們(men)(men)帶(dai)入了交(jiao)流(liu)電(dian)時(shi)代，從此以后(hou)功(gong)(gong)率因數(shu)(shu)就常常伴隨著我們(men)(men)的身邊（一般(ban)功(gong)(gong)率因數(shu)(shu)都是小于1的）。

 下(xia)面就(jiu)給大家講(jiang)一(yi)講(jiang)無功補償(chang)的原理、補償(chang)形式(shi)，供大家學習(xi)參考。

為了降低發電廠的無功供給壓力，我們在供電系統中感性負載消耗較大的點投入相應的電容器來為感性負載提供無功功率，這樣就極大的減輕了發電廠的無功供給壓力。用戶應在提高用電自然功率因數的基礎上，設計和裝設無功補償裝置，并做到隨其負荷和電(dian)(dian)壓變(bian)動及時投入或切(qie)除，防止無(wu)功(gong)(gong)(gong)倒送(song)(song)。同時將用(yong)戶的(de)(de)功(gong)(gong)(gong)率(lv)(lv)因(yin)數(shu)達到相應的(de)(de)標準(zhun)，以(yi)避免供電(dian)(dian)部(bu)門加收力率(lv)(lv)電(dian)(dian)費(fei)。因(yin)此(ci)，無(wu)論(lun)對供電(dian)(dian)部(bu)門還(huan)是(shi)用(yong)電(dian)(dian)部(bu)門，對無(wu)功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)進行自(zi)動補償(chang)以(yi)提高功(gong)(gong)(gong)率(lv)(lv)因(yin)數(shu)，防止無(wu)功(gong)(gong)(gong)倒送(song)(song)，對節(jie)約電(dian)(dian)能、提高運(yun)行質量(liang)都具有(you)非常重要的(de)(de)意義。

一、為什么要進行無功補償？

無功功率絕不是無用功率，在交流供電系統中，電感和電容都是必不可少的負載，如電動機、變壓器等鐵(tie)磁(ci)性負(fu)載(zai)，如(ru)果沒(mei)有感性無功(gong)的勵磁(ci)，設備無法(fa)正常(chang)(chang)工(gong)作，比如(ru)定距(ju)離送電(dian)的線路本身，就(jiu)(jiu)是容性負(fu)載(zai)，只要(yao)是送電(dian)當中就(jiu)(jiu)會相當于電(dian)容器在(zai)工(gong)作。那么也就(jiu)(jiu)是說在(zai)交(jiao)流供電(dian)系統中，無功(gong)的存在(zai)對能量的傳輸和交(jiao)換(huan)有著巨大意(yi)義，不可缺少，或者說離開(kai)無功(gong)功(gong)率(lv)的交(jiao)換(huan)系統就(jiu)(jiu)不能正常(chang)(chang)工(gong)作。

那么，大量的(de)無(wu)功(gong)(gong)由(you)哪里來？系(xi)(xi)統(tong)中眾多的(de)無(wu)功(gong)(gong)負(fu)(fu)載(zai)，尤(you)其是(shi)感(gan)性無(wu)功(gong)(gong)負(fu)(fu)載(zai)，正常來講，這些負(fu)(fu)載(zai)所吸收的(de)無(wu)功(gong)(gong)功(gong)(gong)率是(shi)由(you)發(fa)電(dian)(dian)(dian)(dian)廠提(ti)供(gong)的(de)，也就(jiu)是(shi)說發(fa)電(dian)(dian)(dian)(dian)機在工作時就(jiu)會向系(xi)(xi)統(tong)釋放(fang)有功(gong)(gong)電(dian)(dian)(dian)(dian)能(neng)，同時對感(gan)性負(fu)(fu)載(zai)提(ti)供(gong)相應的(de)無(wu)功(gong)(gong)電(dian)(dian)(dian)(dian)能(neng)。發(fa)電(dian)(dian)(dian)(dian)機運(yun)行時必須要保持適(shi)當的(de)無(wu)功(gong)(gong)輸(shu)出(chu)，如果沒(mei)有無(wu)功(gong)(gong)輸(shu)出(chu)就(jiu)會對發(fa)電(dian)(dian)(dian)(dian)系(xi)(xi)統(tong)造成破壞性的(de)影響,也就(jiu)是(shi)說保護系(xi)(xi)統(tong)的(de)無(wu)功(gong)(gong)平衡至關重(zhong)要。

當系統中無(wu)功(gong)功(gong)率(lv)需求增(zeng)大時，如(ru)果(guo)不在系統人為地安裝無(wu)功(gong)補償(chang)裝置(zhi)，發電(dian)(dian)(dian)廠要(yao)通過調相(xiang)的方式來加大無(wu)功(gong)功(gong)率(lv)輸出(chu)，由于發電(dian)(dian)(dian)機的容量(liang)是(shi)有限的，那(nei)么就(jiu)勢必(bi)要(yao)減少有功(gong)功(gong)率(lv)的輸出(chu)量(liang)，也就(jiu)是(shi)降低(di)(di)發電(dian)(dian)(dian)機的輸出(chu)能力(li)，為滿足用電(dian)(dian)(dian)的要(yao)求，發電(dian)(dian)(dian)機、供(gong)(gong)電(dian)(dian)(dian)線路和變壓器的容量(liang)需增(zeng)大，這(zhe)樣(yang)不僅增(zeng)加供(gong)(gong)電(dian)(dian)(dian)投資、降低(di)(di)設(she)備利(li)用率(lv)，也將增(zeng)加線路損(sun)耗。

二、無功補償的基本原理

一般(ban)在系統中(zhong)(zhong)所說的(de)(de)無(wu)功(gong)(gong)(gong)(gong)負(fu)(fu)(fu)載(zai)(zai)(zai)大(da)部分是感(gan)(gan)性(xing)(xing)無(wu)功(gong)(gong)(gong)(gong)負(fu)(fu)(fu)載(zai)(zai)(zai)，把具有容(rong)(rong)(rong)性(xing)(xing)功(gong)(gong)(gong)(gong)率負(fu)(fu)(fu)荷(he)的(de)(de)裝置(zhi)與感(gan)(gan)性(xing)(xing)功(gong)(gong)(gong)(gong)率負(fu)(fu)(fu)荷(he)并聯(lian)接(jie)在同一電(dian)(dian)路，當感(gan)(gan)性(xing)(xing)無(wu)功(gong)(gong)(gong)(gong)負(fu)(fu)(fu)載(zai)(zai)(zai)吸收(shou)能(neng)(neng)(neng)量(liang)時，容(rong)(rong)(rong)性(xing)(xing)負(fu)(fu)(fu)載(zai)(zai)(zai)釋(shi)放(fang)能(neng)(neng)(neng)量(liang)，而(er)感(gan)(gan)性(xing)(xing)負(fu)(fu)(fu)載(zai)(zai)(zai)釋(shi)放(fang)能(neng)(neng)(neng)量(liang)時，容(rong)(rong)(rong)性(xing)(xing)負(fu)(fu)(fu)荷(he)卻在吸收(shou)能(neng)(neng)(neng)量(liang)，能(neng)(neng)(neng)量(liang)在容(rong)(rong)(rong)性(xing)(xing)負(fu)(fu)(fu)載(zai)(zai)(zai)和感(gan)(gan)性(xing)(xing)負(fu)(fu)(fu)載(zai)(zai)(zai)之間交換(huan)，這(zhe)樣容(rong)(rong)(rong)性(xing)(xing)負(fu)(fu)(fu)載(zai)(zai)(zai)所吸收(shou)的(de)(de)無(wu)功(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)率可以從容(rong)(rong)(rong)性(xing)(xing)負(fu)(fu)(fu)荷(he)裝置(zhi)輸出的(de)(de)無(wu)功(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)率中(zhong)(zhong)得到補償，無(wu)功(gong)(gong)(gong)(gong)功(gong)(gong)(gong)(gong)率就(jiu)地平(ping)衡掉(diao)，以降低(di)線路損失(shi)，提高帶載(zai)(zai)(zai)能(neng)(neng)(neng)力(li)，降低(di)電(dian)(dian)壓損失(shi)及(ji)緩解發電(dian)(dian)廠的(de)(de)供電(dian)(dian)壓力(li)，這(zhe)就(jiu)是無(wu)功(gong)(gong)(gong)(gong)補償的(de)(de)基(ji)本原(yuan)理。

相位分析(xi)無功補償的基本原理：

電(dian)(dian)(dian)(dian)感負(fu)載(zai)中(zhong)電(dian)(dian)(dian)(dian)流IL滯后電(dian)(dian)(dian)(dian)壓90°,而純電(dian)(dian)(dian)(dian)容(rong)的電(dian)(dian)(dian)(dian)流Ic則超前電(dian)(dian)(dian)(dian)壓90°。電(dian)(dian)(dian)(dian)容(rong)中(zhong)的電(dian)(dian)(dian)(dian)流與(yu)電(dian)(dian)(dian)(dian)感中(zhong)的電(dian)(dian)(dian)(dian)流相位相差180°,可以相互抵(di)消。

電(dian)(dian)力系統(tong)中的(de)負(fu)載大部分是感性負(fu)載，因此總(zong)(zong)電(dian)(dian)流(liu)(liu)I將(jiang)滯后電(dian)(dian)壓(ya)一(yi)(yi)個角度Φ1,如果將(jiang)并聯電(dian)(dian)容(rong)器(qi)與負(fu)載并聯，這(zhe)時I′＝I+IC,電(dian)(dian)容(rong)器(qi)的(de)電(dian)(dian)流(liu)(liu)將(jiang)抵(di)消一(yi)(yi)部分電(dian)(dian)感電(dian)(dian)流(liu)(liu)，從(cong)而使總(zong)(zong)電(dian)(dian)流(liu)(liu)從(cong)I降低(di)到I′，相位角由Φ1減(jian)少為Φ2,可以提(ti)高功率因數(shu)，無功就(jiu)地平衡掉。

三(san)、無功補(bu)償的補(bu)償形(xing)式

1）個別(bie)補(bu)償個別(bie)補(bu)償就(jiu)是對(dui)單臺用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)設(she)備所(suo)需(xu)的無(wu)功(gong)(gong)就(jiu)近(jin)補(bu)償的辦法，把電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)直接接到單臺用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)設(she)備的同(tong)一(yi)個電(dian)(dian)(dian)(dian)(dian)氣回路，用(yong)(yong)同(tong)一(yi)臺開關控制，同(tong)時(shi)(shi)投運(yun)(yun)或斷(duan)開。這(zhe)種補(bu)償方(fang)法的效果較好，電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)靠近(jin)用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)設(she)備，就(jiu)地平衡無(wu)功(gong)(gong)電(dian)(dian)(dian)(dian)(dian)流，可避免無(wu)負荷(he)時(shi)(shi)的過補(bu)償，使供電(dian)(dian)(dian)(dian)(dian)質量得到保證。這(zhe)種補(bu)償方(fang)式(shi)常用(yong)(yong)于高低壓(ya)電(dian)(dian)(dian)(dian)(dian)動(dong)機等用(yong)(yong)電(dian)(dian)(dian)(dian)(dian)設(she)備。但這(zhe)種補(bu)償方(fang)式(shi)在用(yong)(yong)戶設(she)備非(fei)連續(xu)運(yun)(yun)轉時(shi)(shi)，電(dian)(dian)(dian)(dian)(dian)容(rong)器(qi)利用(yong)(yong)率低，不能充分發揮其補(bu)償效益。

2）分散補償分散補償是將電容(rong)器分組安裝在車間配電室(shi)或(huo)變(bian)(bian)電所各分路的出線(xian)上，它可與根據系統負荷的變(bian)(bian)化(hua)投(tou)入或(huo)切除(chu)電容(rong)器組，補償效果也比(bi)較好(hao)。但(dan)造(zao)價相(xiang)對(dui)較高。

3）集中補償(chang)集中補償(chang)是(shi)所電(dian)容器組集中安(an)裝在變電(dian)所的一次(ci)或二次(ci)側的母(mu)線上。這種(zhong)補償(chang)方式安(an)裝簡(jian)單，運(yun)行可靠，但(dan)補償(chang)效果較前兩種(zhong)補償(chang)方式差，造(zao)價也相對較高。

四、無功補償的收益

降(jiang)低(di)輸電線(xian)路及變壓器的(de)損(sun)耗合理的(de)補(bu)(bu)償(chang)可(ke)以有效的(de)降(jiang)低(di)系統(tong)電流，以系統(tong)自然功率0.7為例，如(ru)通過(guo)補(bu)(bu)償(chang)裝(zhuang)置將系統(tong)功率因數提高到接近1的(de)水平，系統(tong)電流將下降(jiang)30%左(zuo)右，即(ji)線(xian)路和變壓器的(de)損(sun)耗可(ke)降(jiang)為P=I2R＝(1-30%)2R=0.49R，即(ji)線(xian)路和變壓器損(sun)耗可(ke)降(jiang)低(di)51%。

用電企業的自然(ran)功率因數一般(ban)在0.7左(zuo)右(you)，功率因數從(cong)0.7提高(gao)到(dao)0.95以上線損降低率和變壓(ya)器(qi)的銅損降低率如(ru)下(xia)表：

如果變(bian)壓(ya)(ya)器(qi)及(ji)(ji)(ji)線(xian)(xian)路(lu)小容量不足時，可以(yi)通(tong)過(guo)安裝(zhuang)無(wu)(wu)功(gong)補償裝(zhuang)置(zhi)的方法解決。安裝(zhuang)無(wu)(wu)功(gong)補償裝(zhuang)置(zhi)可以(yi)使無(wu)(wu)功(gong)功(gong)率(lv)就地平衡(heng)，從而減(jian)小流(liu)過(guo)線(xian)(xian)路(lu)及(ji)(ji)(ji)變(bian)壓(ya)(ya)器(qi)的電(dian)流(liu)，減(jian)緩導線(xian)(xian)及(ji)(ji)(ji)變(bian)壓(ya)(ya)器(qi)的絕緣老化速度(du)，延長使用壽命。同時可以(yi)釋放變(bian)壓(ya)(ya)器(qi)及(ji)(ji)(ji)線(xian)(xian)路(lu)的容量，增加變(bian)壓(ya)(ya)器(qi)及(ji)(ji)(ji)線(xian)(xian)路(lu)帶負(fu)荷能(neng)力(li)。

如，有一(yi)臺100KVA變(bian)壓器，目前負載(zai)率為85%,COSΦ=0.7。如果(guo)加裝無功補償設備，可(ke)(ke)使變(bian)壓器釋放30%的帶載(zai)量，用(yong)戶可(ke)(ke)在(zai)變(bian)壓器不(bu)增(zeng)容的情況下，增(zeng)加負載(zai)，進行擴(kuo)大再生(sheng)產。

4） 改善電(dian)壓質(zhi)量(liang)由于系(xi)統存在的大量(liang)感(gan)性負載將造成供(gong)電(dian)線路(lu)(lu)壓降，尤其在供(gong)電(dian)線路(lu)(lu)末(mo)端更為嚴重，通過合理的補償可以有效的緩解線路(lu)(lu)壓降，改善電(dian)能質(zhi)量(liang)。

線(xian)路中(zhong)的電壓損失的計(ji)算(suan)公式如(ru)下：

由于系統的(de)(de)(de)感抗(kang)遠遠大于阻(zu)抗(kang)，從上(shang)式中可以看到(dao),無功的(de)(de)(de)變(bian)化(hua)會引起電(dian)(dian)壓產生(sheng)很大的(de)(de)(de)變(bian)化(hua)。當(dang)線路(lu)中，無功功率Q減小以后(hou)，電(dian)(dian)壓損失也就(jiu)減少了。

對于供電(dian)線(xian)路末(mo)端(duan)電(dian)壓一(yi)般(ban)較低，可通過增加(jia)無功補償裝置來提升線(xian)路末(mo)端(duan)電(dian)壓，使用時(shi)設(she)備安全(quan)可靠運行(xing)。

另一(yi)(yi)方(fang)面，隨著工(gong)業的(de)(de)發展(zhan)，大量(liang)(liang)的(de)(de)自控設(she)備(bei)(bei)及非線性(xing)負載的(de)(de)使用(yong)，使大量(liang)(liang)諧(xie)波在供配電網絡中的(de)(de)流動，污染電網。通(tong)過合(he)理的(de)(de)配置補(bu)償濾波設(she)備(bei)(bei)，抑(yi)制(zhi)或(huo)大幅度降(jiang)低諧(xie)波對供電系統和(he)用(yong)電設(she)備(bei)(bei)的(de)(de)影響是改善電能質量(liang)(liang)的(de)(de)主要手段(duan)之一(yi)(yi)。

5）節約電(dian)費支出(chu)通過合(he)理的補償(chang)，使計量點的功率因數達(da)到國家標準的要求，可(ke)以消除力率電(dian)費，從而使電(dian)力用戶電(dian)費支出(chu)大(da)幅度降低。

注：動(dong)態無(wu)功(gong)(gong)功(gong)(gong)率(lv)補(bu)(bu)償(chang)裝置的有功(gong)(gong)節(jie)能(neng)只是(shi)降低了補(bu)(bu)償(chang)點(dian)至發電機(ji)之間(jian)的供配電的損耗(hao)。所以高壓(ya)網側的無(wu)功(gong)(gong)補(bu)(bu)償(chang)不(bu)能(neng)減少低壓(ya)閥(fa)側的損耗(hao)，亦(yi)不(bu)能(neng)使(shi)低壓(ya)供電變壓(ya)器的利用率(lv)提高，根據較佳補(bu)(bu)償(chang)理論，就地(di)動(dong)態無(wu)功(gong)(gong)功(gong)(gong)率(lv)補(bu)(bu)償(chang)節(jie)能(neng)效果(guo)最為顯著(zhu)。

文章來源 | 網絡，版權歸原作者。如有(you)異議(yi)請告知，我們會及時刪除。