无功补偿的工作原理：

      在(zai)交(jiao)流(liu)电(dian)路(lu)中(zhong)，由电(dian)源供给(ji)负载的电(dian)功(gong)(gong)率(lv)有(you)两种；一种是有(you)功(gong)(gong)功(gong)(gong)率(lv)，一种是无功(gong)(gong)功(gong)(gong)率(lv)。

      有功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)是保持用电(dian)(dian)(dian)设(she)备正(zheng)常(chang)运行所需的(de)电(dian)(dian)(dian)功(gong)(gong)(gong)率(lv)，也就是将电(dian)(dian)(dian)能(neng)转换为其(qi)(qi)他形(xing)式能(neng)量(liang)（机械能(neng)、光能(neng)、热能(neng)）的(de)电(dian)(dian)(dian)功(gong)(gong)(gong)率(lv)。无功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)比较抽象，它用于(yu)电(dian)(dian)(dian)路内电(dian)(dian)(dian)场与(yu)磁(ci)(ci)场的(de)交换，并用来(lai)在(zai)电(dian)(dian)(dian)气设(she)备中建立(li)和维持磁(ci)(ci)场的(de)电(dian)(dian)(dian)功(gong)(gong)(gong)率(lv)。它不对外作功(gong)(gong)(gong)，而是转变为其(qi)(qi)他形(xing)式的(de)能(neng)量(liang)。凡(fan)是有电(dian)(dian)(dian)磁(ci)(ci)线圈的(de)电(dian)(dian)(dian)气设(she)备，要(yao)建立(li)磁(ci)(ci)场，就要(yao)消(xiao)耗无功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)。

      无功(gong)功(gong)率(lv)决不(bu)(bu)是(shi)无用(yong)功(gong)率(lv)，它的(de)用(yong)处(chu)很大。电(dian)动机需要建(jian)立和维持旋转(zhuan)(zhuan)磁场，使转(zhuan)(zhuan)子转(zhuan)(zhuan)动，从而(er)带动机械(xie)运(yun)动，电(dian)动机的(de)转(zhuan)(zhuan)子磁场就是(shi)靠从电(dian)源(yuan)取得无功(gong)功(gong)率(lv)建(jian)立的(de)。变(bian)(bian)压器也同样需要无功(gong)功(gong)率(lv)，才能(neng)(neng)使变(bian)(bian)压器的(de)一次(ci)线圈产生(sheng)磁场，在二次(ci)线圈感(gan)应出电(dian)压。因此，没(mei)有无功(gong)功(gong)率(lv)，电(dian)动机就不(bu)(bu)会(hui)转(zhuan)(zhuan)动，变(bian)(bian)压器也不(bu)(bu)能(neng)(neng)变(bian)(bian)压，交流(liu)接触器不(bu)(bu)会(hui)吸合(he)。

      在正常情(qing)况下(xia)，用(yong)电(dian)(dian)设(she)备不但要(yao)(yao)(yao)从电(dian)(dian)源取得(de)有(you)功(gong)(gong)功(gong)(gong)率，同时还(hai)需(xu)要(yao)(yao)(yao)从电(dian)(dian)源取得(de)无功(gong)(gong)功(gong)(gong)率。如(ru)果电(dian)(dian)网中(zhong)的无功(gong)(gong)功(gong)(gong)率供(gong)不应求(qiu)，用(yong)电(dian)(dian)设(she)备就没有(you)足够(gou)的无功(gong)(gong)功(gong)(gong)率来建立正常的电(dian)(dian)磁场，这(zhei)些用(yong)电(dian)(dian)设(she)备就不能维持在额定情(qing)况下(xia)工作，用(yong)电(dian)(dian)设(she)备的端(duan)电(dian)(dian)压就要(yao)(yao)(yao)下(xia)降，从而影响用(yong)电(dian)(dian)设(she)备的正常运行。

      但是从发电机和高压输电线供给的(de)无功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)远远满足不了负荷的(de)需(xu)要，所(suo)以在电网中(zhong)要设置(zhi)一些(xie)无功(gong)(gong)(gong)补偿装置(zhi)来补充无功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)，以保证用户对无功(gong)(gong)(gong)功(gong)(gong)(gong)率(lv)(lv)的(de)需(xu)要，这样用电设备才能在额定(ding)电压下(xia)工作。

      无功(gong)(gong)补(bu)偿的(de)基本原(yuan)理是：把具有容性功(gong)(gong)率(lv)负荷(he)(he)的(de)装置(zhi)与(yu)感(gan)性功(gong)(gong)率(lv)负荷(he)(he)并联接(jie)在(zai)同一(yi)电路，能量在(zai)两(liang)种负荷(he)(he)之(zhi)间相互交换(huan)。这(zhei)样，感(gan)性负荷(he)(he)所需要的(de)无功(gong)(gong)功(gong)(gong)率(lv)可由容性负荷(he)(he)输(shu)出的(de)无功(gong)(gong)功(gong)(gong)率(lv)补(bu)偿。

      无(wu)功(gong)(gong)补(bu)偿(chang)可以改(gai)善电(dian)能质量、降低电(dian)能损(sun)耗、挖掘发(fa)供电(dian)设(she)备潜力、无(wu)功(gong)(gong)补(bu)偿(chang)减(jian)少(shao)(shao)用户电(dian)费支出，是(shi)一项投资(zi)少(shao)(shao)，收效快(kuai)的(de)节能措施(shi)。不过在确定(ding)无(wu)功(gong)(gong)补(bu)偿(chang)容量时应注意在轻负荷时要避(bi)免过补(bu)偿(chang)，倒送无(wu)功(gong)(gong)功(gong)(gong)率(lv)(lv)势必造成(cheng)功(gong)(gong)率(lv)(lv)损(sun)耗增加；另外功(gong)(gong)率(lv)(lv)因数(shu)越高(gao)，补(bu)偿(chang)容量减(jian)少(shao)(shao)损(sun)耗的(de)作(zuo)用将变小(xiao)，通常情况下，将功(gong)(gong)率(lv)(lv)因数(shu)提高(gao)到(dao)0.95就是(shi)合理补(bu)偿(chang)。