一、影響電纜附件質量的主要因素有哪些
影響電纜附件品質(zhi)的(de)因素是多元的(de),原則上有以(yi)下各幾個方面(mian):
1、電氣性能
電(dian)(dian)(dian)(dian)氣(qi)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)的(de)(de)(de)(de)好(hao)壞是評判電(dian)(dian)(dian)(dian)纜(lan)附件品質的(de)(de)(de)(de)首要(yao)原則。主要(yao)考慮(lv)電(dian)(dian)(dian)(dian)纜(lan)附件的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)場(chang)分布是否(fou)合(he)(he)理(li),改善電(dian)(dian)(dian)(dian)場(chang)分布的(de)(de)(de)(de)措施(shi)是否(fou)恰當,材(cai)料的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)氣(qi)強(qiang)度、介質損耗和(he)產品的(de)(de)(de)(de)絕緣裕(yu)度等(deng)。同時,還(huan)須考慮(lv)電(dian)(dian)(dian)(dian)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)的(de)(de)(de)(de)穩(wen)定(ding)(ding)性(xing)(xing)(xing)(xing),包括電(dian)(dian)(dian)(dian)纜(lan)附件材(cai)料的(de)(de)(de)(de)化學、物理(li)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)和(he)結(jie)構的(de)(de)(de)(de)穩(wen)定(ding)(ding)性(xing)(xing)(xing)(xing)等(deng),例(li)如(ru)應(ying)(ying)力控制材(cai)料性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)是否(fou)穩(wen)定(ding)(ding),應(ying)(ying)力錐是否(fou)易(yi)變形,電(dian)(dian)(dian)(dian)纜(lan)絕緣回縮對電(dian)(dian)(dian)(dian)纜(lan)附件的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)場(chang)分布的(de)(de)(de)(de)影(ying)響及(ji)防止(zhi)措施(shi),各種材(cai)料結(jie)合(he)(he)的(de)(de)(de)(de)相容性(xing)(xing)(xing)(xing),結(jie)合(he)(he)界(jie)面(mian)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)的(de)(de)(de)(de)穩(wen)定(ding)(ding)性(xing)(xing)(xing)(xing)等(deng)。此(ci)外,還(huan)應(ying)(ying)考慮(lv)電(dian)(dian)(dian)(dian)纜(lan)附件的(de)(de)(de)(de)熱(re)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng),如(ru)介質損耗、導(dao)體連接的(de)(de)(de)(de)接觸電(dian)(dian)(dian)(dian)阻及(ji)其穩(wen)定(ding)(ding)性(xing)(xing)(xing)(xing)、熱(re)量的(de)(de)(de)(de)傳導(dao)釋放(fang)、熱(re)脹冷縮對各部件電(dian)(dian)(dian)(dian)性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)和(he)機械性(xing)(xing)(xing)(xing)能(neng)(neng)(neng)的(de)(de)(de)(de)影(ying)響等(deng)。
2、密封性能
密封(feng)防潮(chao)性(xing)能直接(jie)影響電纜附件(jian)的(de)(de)電氣性(xing)能和使(shi)用壽命。終端的(de)(de)密封(feng)結構是否(fou)可靠、穩定。一(yi)般來(lai)說,中間(jian)接(jie)頭也應有一(yi)個與之相匹配金(jin)屬防潮(chao)外(wai)殼,特(te)別(bie)是直埋或使(shi)用在潮(chao)濕環(huan)境(jing)中。
3、機械性能
終端應該有足(zu)夠的抗彎、防震的能(neng)力。中間(jian)接頭應能(neng)承受一定的拉力和防止外力損(sun)傷(shang)的措施(shi)。
4、工藝性能
工(gong)藝(yi)性(xing)能(neng)是(shi)電纜附件設計和(he)選型(xing)的一個重要(yao)的條件,安裝工(gong)藝(yi)應盡量(liang)簡單(dan),便于現場(chang)施工(gong),工(gong)期(qi)短;對現場(chang)環境要(yao)求和(he)對工(gong)人技術(shu)水平(ping)要(yao)求不高;安裝質(zhi)量(liang)容易控制,質(zhi)量(liang)可靠等(deng)。
5、制造廠商的質量保證體系
預(yu)(yu)制(zhi)(zhi)型(xing)電纜附件出廠(chang)時(shi),制(zhi)(zhi)造(zao)廠(chang)提供的(de)是橡膠(jiao)預(yu)(yu)制(zhi)(zhi)件、預(yu)(yu)制(zhi)(zhi)應(ying)力錐、瓷套、外殼(ke)、浸漬劑等零(ling)部(bu)件,在現(xian)場安(an)裝時(shi)再裝配成整體終(zhong)端或接頭,因此,每一(yi)個零(ling)部(bu)件的(de)制(zhi)(zhi)造(zao)質量和(he)安(an)裝工藝(yi)好壞都與產品的(de)最終(zhong)質量直(zhi)接相關。
二、如何選擇電纜附件
1、對電纜接插頭密封的要求
10kV電(dian)纜接插頭(tou)對密(mi)封的(de)(de)要求是很嚴的(de)(de),潮氣(qi)的(de)(de)侵入會使(shi)電(dian)纜接插頭(tou)的(de)(de)絕緣下降,最終會導致電(dian)纜附(fu)件(jian)擊穿。國標GB12706.4明確(que)規定電(dian)纜附(fu)件(jian)應(ying)在水中進行30個恒壓負荷循環(huan)試(shi)驗。美式以及歐(ou)式電(dian)纜接頭(tou)采用橡膠(jiao)制成(cheng),利用橡膠(jiao)回彈力達到密(mi)封效果,十幾(ji)年的(de)(de)運行證(zheng)明是安全可靠的(de)(de)。國內(nei)有(you)些廠家采用環(huan)氧樹脂(zhi)加密(mi)封圈不能(neng)達到很好密(mi)封效果。
2、對電纜接插頭屏蔽層的要求
10kV電(dian)纜接(jie)(jie)插(cha)頭(tou)(tou)應盡量采用帶有(you)屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)的(de)(de)。電(dian)纜接(jie)(jie)插(cha)頭(tou)(tou)的(de)(de)屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)起到(dao)(dao)屏(ping)蔽(bi)和均(jun)勻電(dian)場作(zuo)用,屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)經接(jie)(jie)地表面(mian)電(dian)位為零,人在設備帶電(dian)的(de)(de)情(qing)況下接(jie)(jie)觸不(bu)會發生觸電(dian)危險(xian),而且在惡劣(lie)環境下(洪水、潮(chao)濕)可安全(quan)運(yun)行。屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)在制(zhi)作(zuo)工(gong)藝上(shang)有(you)一次(ci)(ci)將較厚(hou)的(de)(de)屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)與絕(jue)緣層(ceng)(ceng)(ceng)(ceng)硫化成型的(de)(de),也有(you)將屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)二(er)次(ci)(ci)硫化覆蓋(gai)上(shang)的(de)(de),甚至還有(you)將半導(dao)電(dian)漿涂到(dao)(dao)絕(jue)緣層(ceng)(ceng)(ceng)(ceng)上(shang)的(de)(de)。第一種工(gong)藝屏(ping)蔽(bi)層(ceng)(ceng)(ceng)(ceng)厚(hou),且與絕(jue)緣層(ceng)(ceng)(ceng)(ceng)緊密結合,局(ju)部放電(dian)性(xing)能高。其他兩種方法不(bu)能達到(dao)(dao)安全(quan)運(yun)行的(de)(de)要(yao)求。
3、對技術指標的要求
根據(ju)國(guo)標(biao)GB12706.4的要求,國(guo)內10kV電(dian)(dian)纜(lan)系統采用8.7/15kV等級電(dian)(dian)纜(lan)附(fu)件,交流(liu)耐壓(ya)水平為40kV5分鐘,局部放電(dian)(dian)水平為15kV時(shi),≤10Pc.型(xing)式(shi)試驗應在(zai)空(kong)氣中(zhong)和(he)水中(zhong)各進行30個(ge)恒(heng)壓(ya)負(fu)荷(he)循環試驗。動熱(re)穩定(ding)電(dian)(dian)流(liu)一般應大于20kA2秒(miao),200A肘(zhou)型(xing)插頭(tou)則應根據(ju)系統實(shi)際情況選擇。
4、對橡膠種類的要求
目前應用于電纜附件的橡(xiang)(xiang)(xiang)膠(jiao)有(you)兩種(zhong)(zhong):一(yi)種(zhong)(zhong)為(wei)三元乙(yi)丙(bing)橡(xiang)(xiang)(xiang)膠(jiao),一(yi)種(zhong)(zhong)為(wei)硅橡(xiang)(xiang)(xiang)膠(jiao)。這(zhe)兩種(zhong)(zhong)橡(xiang)(xiang)(xiang)膠(jiao)材料(liao)各有(you)其特(te)點。三元乙(yi)丙(bing)橡(xiang)(xiang)(xiang)膠(jiao)絕緣性能(neng)優越,耐老化,強(qiang)力大,但抗紫外(wai)線較差(cha)。硅橡(xiang)(xiang)(xiang)膠(jiao)耐候性好(hao)(hao),絕緣性能(neng)好(hao)(hao)。在國外(wai)制作電(dian)纜(lan)(lan)接(jie)插(cha)頭(tou)(tou)廣泛采(cai)用(yong)三元乙(yi)丙(bing)橡(xiang)(xiang)(xiang)膠(jiao),因為(wei)接(jie)插(cha)頭(tou)(tou)一(yi)般(ban)不受太陽(yang)光紫外(wai)線照(zhao)射,是制作電(dian)纜(lan)(lan)接(jie)插(cha)頭(tou)(tou)的最好(hao)(hao)材料(liao)。電(dian)纜(lan)(lan)冷縮(suo)/預制戶外(wai)終端頭(tou)(tou)則(ze)應采(cai)用(yong)硅橡(xiang)(xiang)(xiang)膠(jiao),充(chong)分利(li)用(yong)其抗紫外(wai)線性能(neng)好(hao)(hao),以及良好(hao)(hao)的憎水(shui)性能(neng)。