電纜故障檢測查找方法：對于非直接短路電纜故障和接地電纜故障，對(dui)于直接短路或(huo)斷線電纜故障用萬用表可(ke)直接測量判斷，用兆歐表遙測芯線間絕(jue)緣(yuan)電阻(zu)或(huo)芯線對(dui)地(di)絕(jue)緣(yuan)電阻(zu)，根據其阻(zu)值(zhi)可(ke)判斷電纜故障類(lei)型。下面介紹電纜故障查找的方法：
高壓(ya)電(dian)橋法就是(shi)用雙(shuang)臂電(dian)橋測(ce)(ce)出電(dian)纜(lan)(lan)(lan)芯(xin)(xin)線(xian)的(de)直(zhi)流電(dian)阻(zu)(zu)(zu)值(zhi)，再(zai)準確測(ce)(ce)量電(dian)纜(lan)(lan)(lan)實際(ji)長度(du)，按照電(dian)纜(lan)(lan)(lan)長度(du)與(yu)電(dian)阻(zu)(zu)(zu)的(de)正比例關系，計算出電(dian)纜(lan)(lan)(lan)故障(zhang)點(dian)。該(gai)方法對(dui)于(yu)(yu)電(dian)纜(lan)(lan)(lan)芯(xin)(xin)線(xian)間(jian)(jian)直(zhi)接(jie)(jie)短(duan)路或短(duan)路點(dian)接(jie)(jie)觸(chu)電(dian)阻(zu)(zu)(zu)小于(yu)(yu)1Ω的(de)故障(zhang)，判(pan)斷誤(wu)差(cha)一(yi)般不大于(yu)(yu)3m，對(dui)于(yu)(yu)故障(zhang)點(dian)接(jie)(jie)觸(chu)電(dian)阻(zu)(zu)(zu)大于(yu)(yu)1Ω的(de)故障(zhang)，可(ke)采用加高電(dian)壓(ya)燒穿(chuan)的(de)方法使電(dian)阻(zu)(zu)(zu)降至(zhi)1Ω以下(xia)，再(zai)按此方法測(ce)(ce)量。測(ce)(ce)量電(dian)路時，首先測(ce)(ce)出芯(xin)(xin)線(xian)a與(yu)b之間(jian)(jian)的(de)電(dian)阻(zu)(zu)(zu)R1，R1=2RX+R其中(zhong)RX為a相或b相至(zhi)電(dian)纜(lan)(lan)(lan)故障(zhang)點(dian)的(de)一(yi)相電(dian)阻(zu)(zu)(zu)值(zhi)，只為短(duan)接(jie)(jie)點(dian)的(de)接(jie)(jie)觸(chu)電(dian)阻(zu)(zu)(zu)。
再就(jiu)電(dian)(dian)(dian)(dian)橋(qiao)移到電(dian)(dian)(dian)(dian)纜的(de)(de)另一端(duan)，測出a1與(yu)b1芯(xin)(xin)(xin)(xin)線間的(de)(de)直流電(dian)(dian)(dian)(dian)阻(zu)值R2，則(ze)(ze)R2=2R（L-X） R，R（L-X）為a1相(xiang)或b1相(xiang)芯(xin)(xin)(xin)(xin)線至電(dian)(dian)(dian)(dian)纜故(gu)(gu)障點(dian)(dian)的(de)(de)一相(xiang)電(dian)(dian)(dian)(dian)阻(zu)值。測完R1與(yu)R2后，再按圖3所示電(dian)(dian)(dian)(dian)路(lu)將b1與(yu)c1短路(lu)，測出b、c兩(liang)相(xiang)芯(xin)(xin)(xin)(xin)線間的(de)(de)直流電(dian)(dian)(dian)(dian)阻(zu)值，則(ze)(ze)該(gai)組織(zhi)的(de)(de)1/2為每相(xiang)芯(xin)(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)值，用(yong)RL表(biao)示，RL=RX R（L-X），由此可(ke)得出故(gu)(gu)障點(dian)(dian)的(de)(de)接觸電(dian)(dian)(dian)(dian)阻(zu)值：R=R1 R2-2RL表(biao)，因此，故(gu)(gu)障點(dian)(dian)兩(liang)側芯(xin)(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)阻(zu)值可(ke)用(yong)下式(shi)表(biao)示：RX=（R1-R）/2，R（L-X）=（R2-R）/2。RX、R（L-X）、RL三(san)個數值確定后，按比例公式(shi)即可(ke)求(qiu)出故(gu)(gu)障點(dian)(dian)距電(dian)(dian)(dian)(dian)纜端(duan)頭(tou)的(de)(de)距離(li)(li)X或（L-X）：X=（RX/RL）L，（L-X）=（R（L-2）在電(dian)(dian)(dian)(dian)纜的(de)(de)末端(duan)在測量(liang)每相(xiang)芯(xin)(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)容電(dian)(dian)(dian)(dian)流Ia1、Ib2、Ic3的(de)(de)數值，以核對完好(hao)芯(xin)(xin)(xin)(xin)線與(yu)斷(duan)(duan)線芯(xin)(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)容之比，初步可(ke)判斷(duan)(duan)出斷(duan)(duan)線距離(li)(li)近似點(dian)(dian)。
所謂(wei)測聲法(fa)(fa)(fa)就是(shi)根據故障(zhang)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)的聲音進行查(cha)找，該(gai)方(fang)法(fa)(fa)(fa)對(dui)(dui)于高(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)芯(xin)(xin)(xin)線對(dui)(dui)絕緣(yuan)層閃絡放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)較為(wei)有效。此方(fang)法(fa)(fa)(fa)所用設(she)(she)備為(wei)直流(liu)耐(nai)壓(ya)試(shi)驗機。其中TB為(wei)高(gao)壓(ya)試(shi)驗變壓(ya)器，C為(wei)高(gao)壓(ya)電(dian)(dian)(dian)(dian)(dian)容(rong)器，VE為(wei)高(gao)壓(ya)整流(liu)硅堆，R為(wei)限流(liu)電(dian)(dian)(dian)(dian)(dian)阻，Q為(wei)放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)球間隙，L為(wei)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)芯(xin)(xin)(xin)線。當電(dian)(dian)(dian)(dian)(dian)容(rong)器C充電(dian)(dian)(dian)(dian)(dian)到一(yi)定(ding)電(dian)(dian)(dian)(dian)(dian)壓(ya)值時，球間隙對(dui)(dui)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)故障(zhang)芯(xin)(xin)(xin)線放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)，在電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)故障(zhang)處(chu)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)芯(xin)(xin)(xin)線對(dui)(dui)絕緣(yuan)層放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)產生“滋、滋”的火花放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)聲，對(dui)(dui)于明敷設(she)(she)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)憑聽覺可直接查(cha)找，若為(wei)地埋電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)，則首先要確定(ding)并標明電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)走向。查(cha)找時，將拾(shi)音器貼近地面，沿電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)走向慢(man)(man)慢(man)(man)移(yi)動，當聽到“滋、滋”放(fang)(fang)電(dian)(dian)(dian)(dian)(dian)聲大時，該(gai)處(chu)即為(wei)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)故障(zhang)點。使用該(gai)方(fang)法(fa)(fa)(fa)一(yi)定(ding)要注意安全(quan)，在試(shi)驗設(she)(she)備端(duan)和電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)末端(duan)應設(she)(she)專人監(jian)看。我公(gong)司(si)生產的電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)故障(zhang)定(ding)位儀不僅可以(yi)測聲，同時可以(yi)檢測磁信號，信號強(qiang)度直觀同步(bu)顯(xian)示，能夠(gou)更快(kuai)更準的定(ding)位電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)故障(zhang)點。
零電位法
零(ling)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)(wei)法(fa)也就是(shi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)(wei)比(bi)較(jiao)(jiao)法(fa)，它適應(ying)于長度較(jiao)(jiao)短的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)芯線(xian)(xian)對地(di)故(gu)(gu)障，應(ying)用(yong)此(ci)(ci)方法(fa)測量(liang)簡便(bian)準確，不需要精密儀(yi)器和(he)復雜計(ji)算。測量(liang)原(yuan)理(li)如(ru)下：將電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)障芯線(xian)(xian)與(yu)等長的(de)(de)(de)(de)比(bi)較(jiao)(jiao)導線(xian)(xian)并(bing)聯，在(zai)(zai)b、c兩端(duan)加電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓VE時(shi)，相當于在(zai)(zai)兩個并(bing)聯的(de)(de)(de)(de)均勻電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻絲(si)(si)兩端(duan)接了電(dian)(dian)(dian)(dian)(dian)(dian)(dian)源，此(ci)(ci)時(shi)，一(yi)條電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻絲(si)(si)上(shang)的(de)(de)(de)(de)任何一(yi)點(dian)(dian)和(he)另(ling)一(yi)條電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻絲(si)(si)上(shang)的(de)(de)(de)(de)對應(ying)點(dian)(dian)之(zhi)間的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)(wei)差必然為(wei)零(ling)，反之(zhi)，電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)(wei)差為(wei)零(ling)的(de)(de)(de)(de)兩點(dian)(dian)必然是(shi)對應(ying)點(dian)(dian)。因為(wei)微(wei)伏(fu)表(biao)的(de)(de)(de)(de)負極接地(di)，與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)障點(dian)(dian)等電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)(wei)，所以，當微(wei)伏(fu)表(biao)的(de)(de)(de)(de)正極在(zai)(zai)比(bi)較(jiao)(jiao)導線(xian)(xian)上(shang)移(yi)動至指示值為(wei)零(ling)時(shi)的(de)(de)(de)(de)點(dian)(dian)與(yu)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)障點(dian)(dian)等電(dian)(dian)(dian)(dian)(dian)(dian)(dian)位(wei)(wei)(wei)，即電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)障點(dian)(dian)的(de)(de)(de)(de)對應(ying)點(dian)(dian)。S為(wei)單相閘刀開關(guan)，E為(wei)6E蓄電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池或4節1號干電(dian)(dian)(dian)(dian)(dian)(dian)(dian)池，G為(wei)直流微(wei)伏(fu)表(biao)，測量(liang)步驟如(ru)下：
a）先在(zai)b和c相芯線(xian)(xian)上(shang)接上(shang)電池E，再(zai)在(zai)地面(mian)上(shang)敷設一(yi)根與故障電纜長度相等的(de)比較導線(xian)(xian)S，該導線(xian)(xian)要用裸銅線(xian)(xian)或裸鋁線(xian)(xian)，其截面(mian)應相等，不能有(you)中間接頭。
b）將微(wei)伏(fu)表的負極接(jie)地(di)，正(zheng)極接(jie)一根較(jiao)長(chang)的軟導(dao)線，導(dao)線另一端(duan)要求在敷設的比較(jiao)導(dao)線上滑(hua)動(dong)時(shi)能(neng)充分接(jie)觸。
c）合上(shang)閘刀開(kai)關S，將軟導線的端頭在比(bi)較導線上(shang)滑(hua)動，當微伏(fu)表(biao)指示為零時的位置(zhi)即為電纜故障點的位置(zhi)。
