護(hu)層(ceng)是(shi)電(dian)(dian)纜(lan)(lan)(lan)外層(ceng)的(de)保(bao)護(hu)部分。根據電(dian)(dian)纜(lan)(lan)(lan)的(de)用(yong)途以(yi)及使用(yong)環境和(he)絕緣(yuan)的(de)不同(tong)，礦用(yong)控制電(dian)(dian)纜(lan)(lan)(lan)，護(hu)層(ceng)有許多(duo)不同(tong)型式和(he)結(jie)構，它們所起的(de)作用(yong)也不盡相同(tong)。絞(jiao)合線芯可以(yi)采(cai)用(yong)非緊壓(ya)和(he)緊壓(ya)線芯兩(liang)種。交聯電(dian)(dian)纜(lan)(lan)(lan) 的(de)導電(dian)(dian)線芯通(tong)常采(cai)用(yong)絞(jiao)合結(jie)構，1kV交聯電(dian)(dian)纜(lan)(lan)(lan)通(tong)常采(cai)用(yong)扇(shan)形(xing)(xing)、半圓(yuan)形(xing)(xing)和(he)圓(yuan)形(xing)(xing)。6kV以(yi)上交聯電(dian)(dian)纜(lan)(lan)(lan)采(cai)用(yong)圓(yuan)形(xing)(xing)緊壓(ya)線芯。電(dian)(dian)力電(dian)(dian)纜(lan)(lan)(lan)主要考(kao)查導體的(de)材質(zhi)和(he)截面(mian)積，若導體的(de)材質(zhi)不好或截面(mian)積嚴(yan)重不足，就會造成導體直流電(dian)(dian)阻嚴(yan)重超標，這(zhe)種電(dian)(dian)纜(lan)(lan)(lan)鋪設在(zai)線路中(zhong)就會增加電(dian)(dian)流在(zai)線路上通(tong)過時的(de)損耗(hao)。

絕(jue)緣(yuan)層的(de)(de)材料必須具有良好的(de)(de)電(dian)氣絕(jue)緣(yuan)性(xing)能，主要(yao)表(biao)現(xian)為承受電(dian)壓(ya)的(de)(de)大小。一般地講，同一質量的(de)(de)絕(jue)緣(yuan)層愈(yu)厚(hou)，耐(nai)電(dian)壓(ya)也越高。交聯聚(ju)乙烯具有優良的(de)(de)電(dian)氣絕(jue)緣(yuan)性(xing)能，經(jing)過(guo)交聯后，它的(de)(de)耐(nai)熱和機械性(xing)能大幅度地提高，是目前理想的(de)(de)絕(jue)緣(yuan)材料。導體包覆絕(jue)緣(yuan)層后稱為絕(jue)緣(yuan)線(xian)芯(xin)。每(mei)個導體上(shang)的(de)(de)絕(jue)緣(yuan)層，稱為線(xian)芯(xin)的(de)(de)絕(jue)緣(yuan)或簡稱芯(xin)絕(jue)緣(yuan)。成品(pin)電(dian)壓(ya)試驗(yan)(yan)及絕(jue)緣(yuan)線(xian)芯(xin)間電(dian)壓(ya)試驗(yan)(yan)不(bu)光(guang)要(yao)求(qiu)電(dian)纜(lan)有足夠的(de)(de)絕(jue)緣(yuan)能力，還要(yao)求(qiu)絕(jue)緣(yuan)或護套(tao)材料均(jun)勻無雜質、厚(hou)度足夠均(jun)勻，表(biao)面不(bu)能有看(kan)不(bu)見的(de)(de)、等，否則就會造成耐(nai)壓(ya)試驗(yan)(yan)時局部(bu)擊穿。

WDZN耐火(huo)電(dian)(dian)(dian)纜的主要特點是電(dian)(dian)(dian)纜除了(le)能(neng)在(zai)(zai)正常的工作(zuo)條件下傳輸(shu)電(dian)(dian)(dian)力外，電(dian)(dian)(dian)纜在(zai)(zai)著火(huo)燃燒時仍能(neng)保持一定時間(jian)的正常運行，適用于站、地鐵、隧道、高層建筑(zhu)等與防(fang)火(huo)安全和消防(fang)救生有關(guan)的地方。電(dian)(dian)(dian)力電(dian)(dian)(dian)纜主要有導體直流(liu)電(dian)(dian)(dian)阻(zu)(zu)、絕(jue)緣電(dian)(dian)(dian)阻(zu)(zu)、成(cheng)品電(dian)(dian)(dian)壓試(shi)驗(yan)及絕(jue)緣線(xian)(xian)芯(xin)間(jian)電(dian)(dian)(dian)壓試(shi)驗(yan)，每(mei)項(xiang)都很重要，導體電(dian)(dian)(dian)阻(zu)(zu)直接(jie)反映了(le)電(dian)(dian)(dian)纜的電(dian)(dian)(dian)傳輸(shu)性能(neng)，直接(jie)影響電(dian)(dian)(dian)纜在(zai)(zai)通(tong)電(dian)(dian)(dian)運行中的溫度、壽(shou)命(ming)、電(dian)(dian)(dian)壓降、以及運行安全。導體是指能(neng)傳導電(dian)(dian)(dian)流(liu)的物體，又稱(cheng)為導電(dian)(dian)(dian)線(xian)(xian)芯(xin)。用作(zuo)電(dian)(dian)(dian)線(xian)(xian)電(dian)(dian)(dian)纜導體的材料，首先要有良好的導電(dian)(dian)(dian)性能(neng)，即電(dian)(dian)(dian)阻(zu)(zu)要小(xiao)，以減少電(dian)(dian)(dian)流(liu)在(zai)(zai)線(xian)(xian)路上的損耗。損耗與電(dian)(dian)(dian)流(liu)大(da)小(xiao)、電(dian)(dian)(dian)阻(zu)(zu)大(da)小(xiao)有直接(jie)關(guan)系，并(bing)表現在(zai)(zai)導體的發(fa)熱(re)上。