一、串聯電抗器和并聯電抗器的區別在哪里
串聯(lian)電(dian)(dian)抗器與并聯(lian)電(dian)(dian)抗器有明(ming)顯區別,體現(xian)在作用和適用范圍上,串聯(lian)電(dian)(dian)抗器主要起限流(liu)和濾波作用,并聯(lian)電(dian)(dian)抗器主要起無功(gong)補償作用,下面做詳細介紹:
1、串(chuan)(chuan)聯電(dian)抗器(qi)是電(dian)力(li)(li)系(xi)統無功補償裝(zhuang)置的重(zhong)要配套(tao)設備。電(dian)力(li)(li)電(dian)容(rong)器(qi)與串(chuan)(chuan)聯電(dian)抗器(qi)串(chuan)(chuan)聯后,能有效地抑(yi)制電(dian)網(wang)中的高次諧波,限制合閘涌流及(ji)操作過電(dian)壓,改善系(xi)統的電(dian)壓波形(xing),提高電(dian)網(wang)功率因數,對電(dian)力(li)(li)電(dian)容(rong)器(qi)及(ji)其它電(dian)力(li)(li)設備的安全運行起到了較(jiao)大的作用。
串聯電抗器主要用(yong)于限制短路電流,而電容(rong)器(qi)組串聯電抗器(qi)可以限制高次(ci)諧波(bo),降低電抗。
2、并聯電(dian)抗器可(ke)以用于補償長(chang)距離(li)輸電(dian)線(xian)路的分布(bu)電(dian)容補償,防止(zhi)空載長(chang)線(xian)路末端電(dian)壓升高(gao)(通常(chang)用于500KV系統),還可(ke)以有(you)利于單(dan)相重合閘(zha)和降低操作過電(dian)壓。
為了(le)提(ti)高(gao)遠(yuan)(yuan)距(ju)離輸電(dian)(dian)(dian)線(xian)路的(de)(de)(de)傳輸能力和改善線(xian)路的(de)(de)(de)運行情況(kuang),削弱(ruo)空載(zai)或(huo)輕載(zai)時(shi)長(chang)線(xian)路的(de)(de)(de)電(dian)(dian)(dian)容效應所(suo)引起的(de)(de)(de)工頻電(dian)(dian)(dian)壓升高(gao),改善沿線(xian)電(dian)(dian)(dian)壓分(fen)布和輕載(zai)線(xian)路中的(de)(de)(de)無功分(fen)布并降低線(xian)損,減(jian)少潛(qian)供(gong)電(dian)(dian)(dian)流(liu),加(jia)速潛(qian)供(gong)電(dian)(dian)(dian)弧的(de)(de)(de)熄滅,提(ti)高(gao)線(xian)路自動重合閘的(de)(de)(de)成功率,并聯電(dian)(dian)(dian)抗器被(bei)廣泛應用于電(dian)(dian)(dian)網的(de)(de)(de)遠(yuan)(yuan)距(ju)離輸配電(dian)(dian)(dian)項目。
二、串聯電抗器的電流大嗎
確定電(dian)容器(qi)串聯電(dian)抗器(qi)回(hui)路(lu)的(de)電(dian)流,應該把(ba)電(dian)容器(qi)和(he)串聯電(dian)抗器(qi)作為一(yi)個(ge)回(hui)路(lu)整體(ti)來(lai)分析,因為補償回(hui)路(lu)中除了要承載正常的(de)基波(bo)無功電(dian)流外,還應該允許它能(neng)夠承載一(yi)定量的(de)某次(ci)諧波(bo)電(dian)流。
串聯電抗器的電容器(qi)補(bu)償(chang)回路(lu),常情況下補(bu)償(chang)容量及(ji)通(tong)過(guo)的電流如(ru)何計算(suan)呢,現舉例(li)如(ru)下:如(ru)果回路(lu)電抗器(qi)的電抗率為(wei)(wei)14%,系統電壓為(wei)(wei)400V。
電容(rong)(rong)(rong)器(qi)(qi)承(cheng)受(shou)的(de)電壓(ya)(ya)(ya)為:400(1-14%)=465.1V,如(ru)果選擇(ze)所配套的(de)電容(rong)(rong)(rong)器(qi)(qi)額定(ding)(ding)電壓(ya)(ya)(ya)為525V(也可以為480V),額定(ding)(ding)電壓(ya)(ya)(ya)525V,容(rong)(rong)(rong)量(liang)為30Kvar的(de)電容(rong)(rong)(rong)器(qi)(qi)額定(ding)(ding)電流(liu)為33A,串聯電抗率14%的(de)后實際發出(chu)30x(465.1/525)2-23.5Kvar,向電網只能補償23.5x(1-14%)=20.1Kvar的(de)無功(gong)功(gong)率,此時通(tong)過電容(rong)(rong)(rong)器(qi)(qi)的(de)電流(liu)23.5/(V3x0.4651)=29.2(A)。此時通(tong)過的(de)電流(liu)遠小于額定(ding)(ding)電流(liu)33A了(le)。
所以串聯電抗器的(de)電流是不大的(de)。