一、礦用橡套軟電纜故障及維修
1、礦用橡套軟電纜損壞種類及其性質
導致礦用橡套軟電纜損(sun)傷的主要原因有井(jing)下環境潮濕,機械外(wai)力(li)致傷,電(dian)纜(lan)絕緣層(ceng)的電(dian)腐蝕(shi),長期過負(fu)荷運行,電(dian)纜(lan)過度彎曲和扭(niu)曲的疲勞(lao)破壞,以及接線工藝(yi)質量差等。電(dian)纜(lan)常(chang)見的故障類型有:短路(lu)、斷線和接地(di)。
(1)短路(lu):指(zhi)電纜的兩(liang)相或三(san)相之間,被潮濕灰(hui)塵(chen),導線和燒灼物接通。
(2)斷(duan)(duan)線(xian)(斷(duan)(duan)路):三相芯線(xian)和地芯線(xian)受電(dian)弧或機械損傷將芯線(xian)中斷(duan)(duan),使電(dian)路形不成通路。
(3)接(jie)地(di):指某(mou)一相(xiang)或(huo)三相(xiang)與接(jie)地(di)芯線(或(huo)設備外殼和(he)大地(di))接(jie)通。
2、電纜故障的測試及查找方法
電纜故(gu)(gu)障的查找,主(zhu)要是依靠儀(yi)器(qi)來進行探測的,針對不同性(xing)質的故(gu)(gu)障,采用不同查找方法。在不通電情況下(xia),通常用兆歐表判斷故(gu)(gu)障性(xing)質。
(1)查短路點。一般通過聞焦(jiao)(jiao)味和(he)看焦(jiao)(jiao)痕,就可(ke)以(yi)找到故障(zhang)點。也可(ke)以(yi)用(yong)手觸(chu),摸到有異常溫度處,即(ji)為短路點。
(2)查斷線(xian)(xian)(xian)點。將電(dian)纜(lan)一端的(de)芯線(xian)(xian)(xian)全部短(duan)接,用(yong)兆歐表分(fen)別測量(liang)另一端主芯線(xian)(xian)(xian)之(zhi)間的(de)電(dian)阻,如(ru)果(guo)某一芯線(xian)(xian)(xian)分(fen)別與其他兩(liang)芯線(xian)(xian)(xian)間電(dian)阻很大(da),說明這(zhe)一芯線(xian)(xian)(xian)斷線(xian)(xian)(xian)。然后用(yong)萬用(yong)表測量(liang)斷線(xian)(xian)(xian)芯線(xian)(xian)(xian)與另一芯線(xian)(xian)(xian)之(zhi)間的(de)電(dian)阻,由檢修人員對電(dian)纜(lan)逐(zhu)段(duan)彎曲或翻動(dong),當彎曲到某一點,萬用(yong)表指針(zhen)有較大(da)擺(bai)動(dong)時(shi),也就找到了故障(zhang)點。
(3)查接地點(dian)。可用驗電(dian)筆(bi)測(ce)電(dian)纜外(wai)皮,當(dang)電(dian)筆(bi)發(fa)亮時,說明該點(dian)發(fa)生接地。當(dang)故障點(dian)不能用直觀法尋找時,必須用電(dian)纜探(tan)(tan)傷儀進行探(tan)(tan)測(ce)。
3、礦用橡套軟電纜接續及護套修復方案
(1)割(ge)切電(dian)纜護(hu)套,當護(hu)套損(sun)(sun)(sun)壞(huai)破(po)口較小,縱向(xiang)長度(du)不超(chao)(chao)過護(hu)套周長,橫向(xiang)長度(du)不超(chao)(chao)過電(dian)纜護(hu)套直徑(jing),并且主線(xian)芯的(de)絕緣(yuan)沒(mei)有損(sun)(sun)(sun)壞(huai)時,可將損(sun)(sun)(sun)壞(huai)部位的(de)周圍(wei)護(hu)套割(ge)去(qu),進(jin)行局部硫化(hua)熱補(bu)修復,護(hu)套破(po)口超(chao)(chao)出上述范圍(wei)或較大(da),但主線(xian)芯絕緣(yuan)沒(mei)有損(sun)(sun)(sun)傷(shang)時,應切掉損(sun)(sun)(sun)傷(shang)部位的(de)一段外護(hu)套,然后再進(jin)行局部硫化(hua)熱補(bu)。
(2)電纜線(xian)(xian)芯(xin)的(de)(de)連(lian)接(jie)。將芯(xin)線(xian)(xian)的(de)(de)兩端按相(xiang)序用搭(da)接(jie)綁(bang)線(xian)(xian)法(fa)或用專用的(de)(de)接(jie)頭鋼管將線(xian)(xian)接(jie)牢(lao),在(zai)接(jie)三相(xiang)芯(xin)線(xian)(xian)的(de)(de)接(jie)頭時,要將各芯(xin)錯開一定長度(du),以保證相(xiang)同的(de)(de)絕緣(yuan)值(zhi)達要求。
(3)當護套和(he)線芯(xin)絕緣(yuan)同(tong)時損(sun)壞(huai),但其主線芯(xin)未斷(duan)時,電(dian)纜護套應(ying)按表1規定(ding)斜長切(qie)除,同(tong)時將芯(xin)線絕緣(yuan)破口外(wai)也切(qie)除。
(4)護(hu)套的(de)(de)修補。先(xian)將已(yi)補好(hao)的(de)(de)線芯(xin)整理好(hao),按一定的(de)(de)捻距絞(jiao)合成型(xing),然后緊繞(rao)扎一層白布帶(dai)(dai)。將已(yi)割好(hao)的(de)(de)護(hu)套斜面(mian)用木挫(cuo)挫(cuo)出新茬,涂上一層漿脂膠(jiao)(jiao),然后將熱(re)補膠(jiao)(jiao)帶(dai)(dai)從(cong)錐形(xing)端依(yi)次緊緊纏(chan)繞(rao)在(zai)(zai)修補段上,纏(chan)時膠(jiao)(jiao)帶(dai)(dai)壓(ya)邊量(liang)應為(wei)50%,并且把膠(jiao)(jiao)帶(dai)(dai)拉伸一定的(de)(de)力(li)量(liang)使之纏(chan)緊。兩端必(bi)須嚴密搭接好(hao),纏(chan)繞(rao)的(de)(de)總厚度比原護(hu)套的(de)(de)外徑(jing)大2~3mm即(ji)可(ke),纏(chan)繞(rao)好(hao)以后,在(zai)(zai)其接頭處涂一層漿脂膠(jiao)(jiao),即(ji)可(ke)進行加熱(re)硫化成型(xing)。
(5)線芯主絕緣和護套的(de)加熱硫(liu)化成(cheng)型(xing)。
①把電纜的修補部分放入電纜熱補器壓膜(mo)胎具中,胎膜(mo)表(biao)面要涂一層水性脫模劑,可防止電纜護(hu)套(tao)和模具粘連,并使護(hu)套(tao)表(biao)面更加光亮。
②給熱補器扣上蓋子,擰動絲桿(gan)手(shou)輪,使胎膜壓緊電纜(lan)。
③開始通電10~15min,溫度(du)升至100℃時,生(sheng)膠變軟,再旋轉熱補器,再壓手輪一次。
④加熱溫度升到170~190℃時(shi)(shi)間(jian)為(wei)10~15min,若(ruo)電纜(lan)直徑較大,可適(shi)當延長時(shi)(shi)間(jian),但一般(ban)為(wei)超過(guo)30min。
⑤停電(dian)(dian)(dian)(dian)(dian)(dian)后(hou),電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)應(ying)放(fang)在胎膜中,待逐步冷卻至100℃時(shi),將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)取出用刀子整形(xing)后(hou),使其平(ping)滑(hua)。經(jing)過修(xiu)補后(hou)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan),要對(dui)(dui)修(xiu)補質(zhi)量進行(xing)(xing)檢驗。用搖表測定其絕(jue)緣(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)阻,對(dui)(dui)額定電(dian)(dian)(dian)(dian)(dian)(dian)壓為6000V的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan),其絕(jue)緣(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)阻要大于400MΩ,對(dui)(dui)1140V以(yi)下的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan),其絕(jue)緣(yuan)電(dian)(dian)(dian)(dian)(dian)(dian)阻要大于10MΩ。檢修(xiu)后(hou)的(de)(de)橡(xiang)套電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)還必須進行(xing)(xing)浸(jin)水(shui)耐壓試(shi)(shi)(shi)驗,試(shi)(shi)(shi)驗時(shi)將(jiang)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)浸(jin)入(ru)水(shui)2h以(yi)上(shang),但電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)的(de)(de)兩端要露出水(shui)面,然后(hou)將(jiang)一根線的(de)(de)線芯接試(shi)(shi)(shi)驗電(dian)(dian)(dian)(dian)(dian)(dian)源,其余線芯短路接地。做耐壓試(shi)(shi)(shi)驗時(shi),對(dui)(dui)不同(tong)電(dian)(dian)(dian)(dian)(dian)(dian)壓等級的(de)(de)橡(xiang)套電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)應(ying)采用交流(liu)50Hz,2倍額定電(dian)(dian)(dian)(dian)(dian)(dian)壓加(jia)1kV試(shi)(shi)(shi)驗電(dian)(dian)(dian)(dian)(dian)(dian)壓進行(xing)(xing)試(shi)(shi)(shi)驗,耐壓時(shi)間為5min,電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)絕(jue)緣(yuan)不被(bei)擊穿,即為合格。
對(dui)于礦用(yong)(yong)橡(xiang)套電(dian)(dian)纜,因其(qi)用(yong)(yong)于煤礦井(jing)(jing)下較為惡劣的(de)環境(jing),電(dian)(dian)纜極(ji)易損傷(shang),而且修復質(zhi)量的(de)好壞又直接影響到井(jing)(jing)下設備使用(yong)(yong)的(de)安全,以及修補后電(dian)(dian)纜的(de)使用(yong)(yong)壽命。因而必須提高修理人員的(de)技術水平和修理技巧,改(gai)進電(dian)(dian)纜修補工藝,力保(bao)基本上完(wan)全恢復礦用(yong)(yong)電(dian)(dian)纜的(de)原有結(jie)構,達(da)到防(fang)爆(bao)和阻燃各方面的(de)性能(neng)要(yao)求,確(que)保(bao)滿(man)足(zu)井(jing)(jing)下各種用(yong)(yong)電(dian)(dian)設備的(de)要(yao)求。
二、礦用電纜運行和維護方法
礦用電纜的(de)運行維護主要是防(fang)止電纜絕緣受熱、受潮、及機械損傷引起的(de)短路(lu)(lu)、斷路(lu)(lu)、漏電等事(shi)故的(de)發生。
1、電纜的巡視
礦井(jing)中的(de)電(dian)(dian)纜由于環(huan)境不好,應(ying)加(jia)強巡(xun)視(shi);立井(jing)和(he)斜(xie)井(jing)井(jing)筒中敷設的(de)電(dian)(dian)纜,應(ying)由專(zhuan)職電(dian)(dian)工(gong)(gong)每(mei)月至(zhi)少(shao)巡(xun)查一(yi)次。井(jing)底車場、大巷、采區運輸巷道和(he)配電(dian)(dian)硐室(shi)敷設的(de)電(dian)(dian)纜,應(ying)由專(zhuan)職電(dian)(dian)工(gong)(gong)每(mei)周至(zhi)少(shao)巡(xun)視(shi)一(yi)次。巡(xun)視(shi)的(de)主要內容如下:
電(dian)(dian)纜有(you)(you)無機械損(sun)(sun)傷,鎧裝層(ceng)有(you)(you)無松散及(ji)嚴重銹蝕。固定電(dian)(dian)纜的(de)(de)卡子(zi)有(you)(you)無松動、損(sun)(sun)壞。懸掛是否合(he)格。電(dian)(dian)纜兩端引入及(ji)引出部分有(you)(you)無異狀(zhuang)。檢(jian)查(cha)接線盒(he)的(de)(de)地線是否完好,接線盒(he)的(de)(de)表面溫度是否過高。通過峒(tong)室和墻壁的(de)(de)電(dian)(dian)纜應有(you)(you)保護管,密封可靠,無被擠壓破損(sun)(sun)現象(xiang)。電(dian)(dian)纜的(de)(de)標牌應符(fu)合(he)要求,無損(sun)(sun)壞。電(dian)(dian)纜與電(dian)(dian)力設備的(de)(de)連接應符(fu)合(he)防爆要求,無不合(he)格接頭(tou)。
流動(dong)(dong)設備(bei)的電(dian)(dian)纜(lan)(lan),如(ru)采煤機(ji)(ji)組、刮板(ban)輸送機(ji)(ji)、裝(zhuang)載機(ji)(ji)、小(xiao)絞車(che)、回柱絞車(che)、煤電(dian)(dian)鉆(zhan)等的電(dian)(dian)纜(lan)(lan),每班應有(you)專人檢查,嚴防碰、砸(za)、擠、壓。停電(dian)(dian)后電(dian)(dian)纜(lan)(lan)要妥(tuo)善盤放,為防止電(dian)(dian)纜(lan)(lan)發(fa)熱(re)著(zhu)火(huo),在帶電(dian)(dian)情況下不準呈0字(zi)或8字(zi)盤放(采掘(jue)機(ji)(ji)用(yong)電(dian)(dian)纜(lan)(lan)除(chu)外)。礦用(yong)橡套電(dian)(dian)纜(lan)(lan)與(yu)防爆三通、四通、插銷(xiao)及母線盒等的連(lian)接(jie)點,應由專人每月(yue)檢查一(yi)次,特別要注(zhu)意連(lian)接(jie)處是否有(you)松動(dong)(dong)和接(jie)觸(chu)不良(liang)的現象。
2、電纜的運行與維護
新安裝的電纜投入運行時,應由電工跟班全面測定負荷電流及電壓損失,并檢查電纜接頭有無發熱現象,發現問題及時處理。無(wu)外被(bei)層鎧裝(zhuang)電(dian)纜(lan)的鎧裝(zhuang)層應定期涂(tu)防腐漆,一般每兩年進行一次(ci)。
鎧裝電纜的鋼帶或鋼絲如有斷裂應及時綁扎。高壓電纜在巷道中跨越電機車架線時,電纜的跨越部分應加膠皮被覆,防止架線火花灼傷電纜麻皮和鎧裝。電纜線路穿過淋水區時,最好不設接線盒,如有接線盒時,應嚴密遮蓋,并由專人經常檢查。為了減少雜散電流對鎧裝電纜的腐蝕,應定期測量電纜鉛(qian)包中的雜散電流密度(du),凡(fan)超過規(gui)定值時(shi),必須采取措施(shi)加(jia)以(yi)解決(jue)。
用溫(wen)度表(biao)測量運行中(zhong)電(dian)纜(lan)的(de)外皮溫(wen)度,3kv以上的(de)油浸紙電(dian)纜(lan)外皮溫(wen)度應不大(da)于(yu)(yu)35℃;高壓(ya)接線盒的(de)表(biao)面溫(wen)度應不大(da)于(yu)(yu)45℃;交聯聚乙烯絕緣電(dian)纜(lan)外皮溫(wen)度應不大(da)于(yu)(yu)55℃。3kv及以下的(de)電(dian)纜(lan)外皮溫(wen)度應不大(da)于(yu)(yu)50℃。
在緊急事故狀態(tai)下(xia),電(dian)纜允(yun)許短時(shi)(shi)間(jian)過(guo)(guo)負荷,但(dan)只允(yun)許超過(guo)(guo)額定(ding)負荷的10%(3kv及以下(xia))和15%(3kv以上),并且不超過(guo)(guo)兩個小時(shi)(shi)。
應每年進行一次絕緣電阻的測定,其絕緣電阻值應符合規定。如果(guo)測試的(de)絕緣(yuan)電(dian)阻(zu)比規定(ding)的(de)數值(zhi)有明顯降低,應(ying)考慮電(dian)纜(lan)受潮(chao)、受損傷和有缺陷(xian),或者接線盒有問題,應(ying)做泄漏電(dian)流試驗和耐壓(ya)試驗進一(yi)步查到原因。用(yong)絕緣(yuan)電(dian)阻(zu)隨時(shi)間變化的(de)關(guan)系,即吸(xi)(xi)收比來判定(ding)電(dian)纜(lan)是(shi)否受潮(chao)。一(yi)般取加壓(ya)后15秒(miao)與60秒(miao)絕緣(yuan)電(dian)阻(zu)的(de)比值(zhi)。油浸紙(zhi)紙(zhi)絕緣(yuan)電(dian)纜(lan)吸(xi)(xi)收比應(ying)不(bu)小于2。吸(xi)(xi)收比越(yue)小,說明絕緣(yuan)越(yue)潮(chao)濕或所含雜質越(yue)多,應(ying)加熱烘干。
測量泄(xie)漏電(dian)(dian)流(liu)及直流(liu)耐(nai)壓試驗(yan)應(ying)每年進行一(yi)次。兩個試驗(yan)的方(fang)法和(he)接線(xian)完全相(xiang)同(tong),是在絕(jue)緣(yuan)(yuan)體(ti)上加(jia)一(yi)個逐漸升高到幾倍于額定(ding)電(dian)(dian)壓的直流(liu)電(dian)(dian)壓,觀察絕(jue)緣(yuan)(yuan)中泄(xie)漏電(dian)(dian)流(liu)的變化。當泄(xie)漏電(dian)(dian)流(liu)與(yu)電(dian)(dian)壓不成比例迅速增加(jia)時,甚至發(fa)生絕(jue)緣(yuan)(yuan)擊穿(chuan)現(xian)象,說明電(dian)(dian)纜絕(jue)緣(yuan)(yuan)有局部缺陷和(he)均勻整(zheng)體(ti)性缺陷,如老化、受潮等。