電纜防水的探討
發布時間:2014-08-09
自1967年發現XLPE絕緣水樹老化後,目前已確認它成為XLPEdianlanlaohuadezhuyaoxianxiangzhiyi。suiranshuishuzhidejiliheruheyinqipohuaimuqianshangbuwanquanqingchu,danshidaliangshiyanshujuxianshishuishuzhihuizaochengjubuyinglizengjia,kenengchengweidianshuzhidefayuandi。gaowenxia,shuishuzhilikenengfashengxianzhudeyanghua,daozhixishuixingzengda,daodianxingzenggao,zuizhongrejichuan;即ji使shi在zai低di溫wen下xia,水shui樹shu枝zhi經jing較jiao長chang時shi間jian氧yang化hua或huo轉zhuan化hua為wei電dian樹shu枝zhi,也ye會hui造zao成cheng絕jue緣yuan的de破po壞huai。特te別bie是shi當dang電dian纜lan長chang期qi浸jin泡pao在zai水shui中zhong時shi,如ru果guo沒mei有you很hen好hao的de防fang水shui結jie構gou,那na麼me電dian纜lan更geng容rong易yi產chan生sheng絕jue緣yuan的de水shui樹shu枝zhi老lao化hua,從cong而er造zao成cheng絕jue緣yuan的de破po壞huai,這zhe樣yang將jiang會hui大da大da縮suo短duan電dian纜lan的de壽shou命ming。所suo以yi敷fu設she在zai有you水shui環huan境jing中zhong的de電dian纜lan一yi般ban都dou需xu要yao電dian纜lan具ju有you防fang水shui結jie構gou。
一、電纜防水結構類型: 對於中壓XLPE絕緣電力電纜來說,通常有以下幾種防水結構:
①duiyudanxindianlanlaishuo,zaidianlandejueyuanpingbicengshangraobaobandaodianzushuidai,zaijinshupingbicengwaimianraobaoputongzushuidai,ranhoujibaowaihutao,waihutaocailiaokeyishiputongdePVC,也可采用具有徑向阻水功能的HDPE材料或低煙無鹵阻燃護套料,可視電纜其它性能要求而定;duiyusanxindianlanzeweilebaozhengjinshupingbidechongfenjiechu,zhizaijueyuanpingbiwaimianraobaodandaodianzushuidai,jinshupingbiwaibuzairaozushuidai,shifangshuixingnengyaoqiudegaodi,tianchongkecaiyongputongtianchonghuozushuitianchong,neichencengjiwaihutaocailiaotongdanxindianlanzhongsuoshu;
②在外護套或內襯層的內部縱包鋁塑複合帶層作為
防水層;
③直接在電纜外部擠包HDPE外護套。
對於110kV級以上XLPEjueyuandianlanlaishuo,zezhuyaocaiyongjinshuhucengshidianlandadaofangshuiyaoqiu。jinshuhucengdezuidatedianshijuyouwanquanbutouguoxing,gujuyoujinshuhutaodedianlanjuyoufeichanghaodejingxiangzushuixingneng。jinshuhucengzhongleizhuyaoyou:熱壓鋁套、熱壓鉛套、焊接皺紋鋁套、焊接皺紋鋼套、冷拔金屬套等。
二、電纜防水形式:
電纜的防水方式一般分為縱向阻水和徑向徑水兩種。縱向阻水一般常用的有阻水紗、阻zu水shui粉fen及ji阻zu水shui帶dai,它ta們men的de阻zu水shui機ji理li是shi在zai這zhe些xie材cai料liao中zhong含han有you一yi種zhong遇yu水shui可ke膨peng脹zhang的de材cai料liao,當dang水shui份fen從cong電dian纜lan端duan頭tou或huo是shi從cong護hu套tao缺que陷xian中zhong進jin入ru後hou,這zhe種zhong材cai料liao就jiu會hui遇yu水shui迅xun速su膨peng脹zhang阻zu止zhi水shui份fen沿yan電dian纜lan縱zong向xiang進jin一yi步bu擴kuo散san,這zhe樣yang就jiu實shi現xian了le電dian纜lan縱zong向xiang防fang水shui的de目mu的de。徑jing向xiang阻zu水shui則ze主zhu要yao通tong過guo擠ji包baoHDPE非金屬護層或熱壓、焊接、冷拔金屬護套方式實現。 三、電纜防水試驗依據:
電纜防水試驗方法,電纜縱向阻水性能目前可以通過IEC 60502-1997 ANNEX D(normative)或GB/T 12706.2-2002附錄D(標準性目錄)透水試驗來進行試驗和判定;而電纜徑向阻水性能,目前主要是通過間接的方法進行確定,比如檢查HDPE非(fei)金(jin)屬(shu)護(hu)套(tao)的(de)或(huo)非(fei)金(jin)屬(shu)護(hu)套(tao)是(shi)否(fou)有(you)缺(que)陷(xian),如(ru)果(guo)這(zhe)些(xie)護(hu)套(tao)被(bei)確(que)定(ding)為(wei)完(wan)好(hao)的(de),那(na)麼(me)就(jiu)認(ren)為(wei)電(dian)纜(lan)具(ju)有(you)良(liang)好(hao)的(de)徑(jing)向(xiang)阻(zu)水(shui)性(xing)能(neng)。但(dan)這(zhe)種(zhong)方(fang)法(fa)有(you)很(hen)多(duo)用(yong)戶(hu)都(dou)提(ti)出(chu)了(le)一(yi)些(xie)疑(yi)問(wen),也(ye)引(yin)起(qi)一(yi)些(xie)爭(zheng)端(duan),缺(que)少(shao)說(shuo)服(fu)力(li),所(suo)以(yi)電(dian)纜(lan)製(zhi)造(zao)廠(chang)家(jia)及(ji)用(yong)戶(hu)現(xian)在(zai)都(dou)迫(po)切(qie)需(xu)要(yao)有(you)一(yi)種(zhong)試(shi)驗(yan)方(fang)法(fa)對(dui)電(dian)纜(lan)的(de)徑(jing)向(xiang)阻(zu)水(shui)性(xing)能(neng)做(zuo)出(chu)判(pan)定(ding),那(na)樣(yang)就(jiu)可(ke)以(yi)避(bi)免(mian)製(zhi)造(zao)廠(chang)家(jia)與(yu)用(yong)戶(hu)因(yin)缺(que)少(shao)徑(jing)向(xiang)阻(zu)水(shui)試(shi)驗(yan)方(fang)法(fa)而(er)對(dui)電(dian)纜(lan)徑(jing)向(xiang)阻(zu)水(shui)性(xing)能(neng)引(yin)起(qi)的(de)爭(zheng)議(yi)。
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