1、掩(yan)護(hu)緊張濾(lv)波補償裝置(zhi)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)的(de)(de)(de)(de)(de)自啟動(dong)。當(dang)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)消散(san)或低落時，電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)的(de)(de)(de)(de)(de)轉(zhuan)(zhuan)速降低。當(dang)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)規復時，在電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)自啟動(dong)時啟動(dong)電(dian)(dian)(dian)(dian)(dian)流比(bi)額外電(dian)(dian)(dian)(dian)(dian)流大(da)好幾倍，將使電(dian)(dian)(dian)(dian)(dian)網(wang)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降加(jia)大(da)，使電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)規復的(de)(de)(de)(de)(de)進(jin)程延伸，增加(jia)了電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)到(dao)達失(shi)常轉(zhuan)(zhuan)速的(de)(de)(de)(de)(de)難度，重大(da)時乃至(zhi)不(bu)克(ke)不(bu)及自啟動(dong)，必需切除一部(bu)分不(bu)緊張的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)，使電(dian)(dian)(dian)(dian)(dian)網(wang)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降削(xue)減。是(shi)以，在不(bu)緊張的(de)(de)(de)(de)(de)和次要(yao)的(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)上可裝設低電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)掩(yan)護(hu)，當(dang)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)消散(san)或低落時舉(ju)措，將電(dian)(dian)(dian)(dian)(dian)動(dong)機(ji)(ji)從電(dian)(dian)(dian)(dian)(dian)網(wang)上斷開。

2、包管機(ji)(ji)(ji)組及裝備平安(an)。當電(dian)(dian)(dian)壓(ya)歷久消散機(ji)(ji)(ji)（如(ru)10S閣(ge)下），依據技巧平安(an)的(de)前提(ti)及臨盆(pen)工藝進程(cheng)的(de)特色，需(xu)將某些電(dian)(dian)(dian)動機(ji)(ji)(ji)切(qie)除。由于(yu)(yu)在這段(duan)光陰(yin)內(nei)汽鍋已(yi)燃燒，電(dian)(dian)(dian)動機(ji)(ji)(ji)自啟(qi)動曾經沒(mei)有(you)需(xu)要了，以是應(ying)(ying)裝設低電(dian)(dian)(dian)壓(ya)掩護舉(ju)措于(yu)(yu)跳(tiao)閘(zha)。別的(de)，另有(you)一些帶恒定(ding)阻力矩(ju)機(ji)(ji)(ji)器的(de)電(dian)(dian)(dian)動機(ji)(ji)(ji)，如(ru)磨煤(mei)機(ji)(ji)(ji)等，在電(dian)(dian)(dian)壓(ya)低落時不可能自啟(qi)動，這些電(dian)(dian)(dian)動機(ji)(ji)(ji)也應(ying)(ying)在電(dian)(dian)(dian)壓(ya)低落時切(qie)除。    

不管是(shi)在(zai)電(dian)(dian)壓完整消散(san)機，或電(dian)(dian)網內的短路毛(mao)病惹(re)起電(dian)(dian)動機制動時，低(di)電(dian)(dian)壓掩(yan)護該當可以或許包管將電(dian)(dian)動機靠(kao)得住斷(duan)開。為此，低(di)電(dian)(dian)壓掩(yan)護應(ying)滿意(yi)如下幾點請求：

1、能反應對稱的和不對稱的電(dian)壓降低。由(you)于在不對稱短路時(shi)的電(dian)動(dong)機也(ye)(ye)可能被制動(dong)，是以(yi)當電(dian)壓規復(fu)時(shi)也(ye)(ye)會(hui)呈現自啟動(dong)成績。

2、電(dian)壓互感器(qi)(PT)一次(ci)側一相或兩相斷(duan)線，二(er)(er)次(ci)側各相斷(duan)線時(shi)（三(san)期(qi)為二(er)(er)次(ci)電(dian)壓小(xiao)開關QF1、QF2、QF3），掩護(hu)裝置不該誤舉措，而且收回“PT斷(duan)線”旌(jing)旗燈號(hao)。但在二(er)(er)次(ci)回路斷(duan)線毛病時(shi)代，假(jia)如廠用母線真(zhen)正落空電(dian)壓（或電(dian)壓降到規(gui)定值時(shi)），低電(dian)壓掩護(hu)仍應準確舉措。

3、0.5s與9s的(de)(de)低電(dian)壓掩(yan)(yan)護的(de)(de)舉(ju)措(cuo)電(dian)壓應(ying)分離(li)整定。在電(dian)壓消散(san)機，用接在線電(dian)壓上的(de)(de)一只(zhi)低電(dian)壓繼(ji)電(dian)器(qi)組成的(de)(de)掩(yan)(yan)護就可以(yi)到達目的(de)(de)，并能(neng)靠得住(zhu)的(de)(de)反響(xiang)三相短(duan)路(lu)。但(dan)當兩相短(duan)路(lu)時(shi)，用一只(zhi)電(dian)壓繼(ji)電(dian)器(qi)組成的(de)(de)掩(yan)(yan)護，只(zhi)要在接繼(ji)電(dian)器(qi)的(de)(de)兩相間產生短(duan)路(lu)時(shi)能(neng)力起感化(hua)，是以(yi)不克不及完整反響(xiang)不對稱的(de)(de)電(dian)壓降低。為了(le)包管在一切兩相短(duan)路(lu)的(de)(de)情(qing)況下掩(yan)(yan)護都能(neng)舉(ju)措(cuo)，應(ying)采納三相繼(ji)電(dian)器(qi)接線方法。

4、同一段廠用母線(xian)供電(dian)的多少(shao)臺電(dian)動機，平日配合裝一套低電(dian)壓掩護裝置，低電(dian)壓繼電(dian)器接在廠用母線(xian)PT上。     

 三(san)期6KV母線PT接(jie)(jie)線方法(fa)為YN/yn/△型。一次(ci)繞組中三(san)相(xiang)(xiang)各串接(jie)(jie)有(you)一只(zhi)高壓(ya)熔絲(si)。第(di)一組二(er)次(ci)繞組上(shang)三(san)相(xiang)(xiang)分離有(you)響(xiang)應的(de)(de)二(er)次(ci)電壓(ya)小開關QF1、QF2、QF3，四只(zhi)低(di)電壓(ya)繼電器(qi)(qi)分離跨(kua)接(jie)(jie)在ab，bc，ca相(xiang)(xiang)間的(de)(de)（此(ci)中有(you)兩個并聯同接(jie)(jie)在ca相(xiang)(xiang)間），分離毛(mao)病(bing)錄(lu)波(bo)器(qi)(qi)、廠(chang)用電快切以(yi)及(ji)到電壓(ya)變送器(qi)(qi)用于(yu)DCS畫面電壓(ya)表(biao)現(xian)以(yi)及(ji)到當場(chang)節(jie)制柜上(shang)用于(yu)電壓(ya)表(biao)表(biao)現(xian)。第(di)二(er)組二(er)次(ci)繞組為啟齒三(san)角形加消諧(xie)器(qi)(qi)，也(ye)稱二(er)次(ci)消諧(xie)器(qi)(qi)。      

失常(chang)時，四個低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓繼(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器均得(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)。假(jia)如母(mu)線(xian)(xian)PT一相(xiang)斷線(xian)(xian)，此中兩只(zhi)繼(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器將(jiang)失電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)舉措(cuo)，并(bing)使(shi)(shi)(shi)PT斷線(xian)(xian)中央繼(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器得(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)舉措(cuo)，收回“母(mu)線(xian)(xian)PT斷線(xian)(xian)”報警，同時閉鎖低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓掩(yan)護(hu)回路舉措(cuo)。假(jia)如母(mu)線(xian)(xian)PT兩相(xiang)及以上斷線(xian)(xian)或許母(mu)線(xian)(xian)失電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，則使(shi)(shi)(shi)四只(zhi)低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓繼(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器全體(ti)失電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)，使(shi)(shi)(shi)得(de)光(guang)陰(yin)繼(ji)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器得(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian) ，經響應(ying)延時收回低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓旌旗(qi)燈(deng)號，低(di)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓掩(yan)護(hu)舉措(cuo)，跳去母(mu)線(xian)(xian)上全體(ti)負荷開(kai)關。