常見故障

一是在礦(kuang)井(jing)供(gong)(gong)電(dian)系(xi)統(tong)中，最常見的短路(lu)故(gu)障類型有(you)三相短路(lu)、兩相短路(lu)和單(dan)相接(jie)地短路(lu)。二是過載故(gu)障是煤礦(kuang)井(jing)下供(gong)(gong)電(dian)系(xi)統(tong)的不正常運行(xing)狀態，過載后電(dian)網的電(dian)流(liu)相位(wei)對稱，幅值大于整定電(dian)流(liu)，當設(she)備的運行(xing)溫度(du)超過其允許(xu)溫升時，就要(yao)對電(dian)網進(jin)行(xing)保護。三是由于礦(kuang)井(jing)中大部分供(gong)(gong)電(dian)線(xian)路(lu)為電(dian)纜(lan)供(gong)(gong)電(dian)，井(jing)下空間狹小，環境惡劣，陰暗潮濕，供(gong)(gong)電(dian)電(dian)纜(lan)的受潮和機械(xie)損(sun)傷使電(dian)纜(lan)經常發生(sheng)單(dan)相漏電(dian)故(gu)障。

解決措施

（1）針對上述各種短路故障時的特征，三相號幅值大小和系統電壓、電流的相位差即功率因數，就可以有效的將起動電流與短路電流區分開來，使短路保護可靠性得到提高；其它幾種不對稱短路故障電網中都會產生負序電流分量，根據負序電流的大小來判斷不對稱短路故障，故采取斷相保護原理。

（2）選(xuan)(xuan)擇基于零序(xu)功率方(fang)向(xiang)的礦井(jing)低壓電(dian)(dian)(dian)(dian)網選(xuan)(xuan)擇性漏(lou)(lou)電(dian)(dian)(dian)(dian)保(bao)護(hu)技術作為礦用(yong)隔爆負荷中(zhong)心(xin)選(xuan)(xuan)擇性漏(lou)(lou)電(dian)(dian)(dian)(dian)保(bao)護(hu)。該系(xi)統由總(zong)饋電(dian)(dian)(dian)(dian)開(kai)關(guan)和分饋電(dian)(dian)(dian)(dian)開(kai)關(guan)聯合(he)構成(cheng)(cheng)，總(zong)開(kai)關(guan)采(cai)用(yong)附(fu)加直流電(dian)(dian)(dian)(dian)源(yuan)檢(jian)(jian)測原(yuan)理檢(jian)(jian)測是否(fou)發生漏(lou)(lou)電(dian)(dian)(dian)(dian)，分開(kai)關(guan)采(cai)用(yong)零序(xu)功率方(fang)向(xiang)檢(jian)(jian)測原(yuan)理判(pan)斷發生漏(lou)(lou)電(dian)(dian)(dian)(dian)故(gu)障(zhang)的線路。附(fu)加直流電(dian)(dian)(dian)(dian)源(yuan)檢(jian)(jian)測原(yuan)理與零序(xu)功率方(fang)向(xiang)檢(jian)(jian)測原(yuan)理的結合(he)，可以保(bao)證(zheng)電(dian)(dian)(dian)(dian)網漏(lou)(lou)電(dian)(dian)(dian)(dian)保(bao)護(hu)動(dong)作的瞬動(dong)性和電(dian)(dian)(dian)(dian)網對稱漏(lou)(lou)電(dian)(dian)(dian)(dian)時(shi)保(bao)護(hu)動(dong)作電(dian)(dian)(dian)(dian)阻值的穩定性，還(huan)可以有效(xiao)的避免傳統單一方(fang)法(fa)無法(fa)對漏(lou)(lou)電(dian)(dian)(dian)(dian)故(gu)障(zhang)線路做(zuo)出有效(xiao)選(xuan)(xuan)擇的弊端(duan)，極大(da)程度(du)的縮小因漏(lou)(lou)電(dian)(dian)(dian)(dian)保(bao)護(hu)造成(cheng)(cheng)的斷電(dian)(dian)(dian)(dian)范圍，既可完(wan)成(cheng)(cheng)井(jing)下低壓電(dian)(dian)(dian)(dian)網單相漏(lou)(lou)電(dian)(dian)(dian)(dian)時(shi)的橫向(xiang)選(xuan)(xuan)擇性和縱(zong)向(xiang)選(xuan)(xuan)擇性保(bao)護(hu)功能。