電纜故障檢測查找方法，你應該懂的

標簽： 電纜故障測試儀

　　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)(dui)于直接短路或斷線(xian)電(dian)纜(lan)故障用(yong)(yong)萬用(yong)(yong)表可直接測量判斷，用(yong)(yong)兆歐表遙測芯(xin)線(xian)間絕(jue)緣電(dian)阻或芯(xin)線(xian)對(dui)(dui)地絕(jue)緣電(dian)阻，根據其阻值可判斷電(dian)纜(lan)故障類型。下面介紹(shao)電(dian)纜(lan)故障查找的方(fang)法：

高(gao)壓電橋法

　　高壓電(dian)(dian)(dian)橋法(fa)就是(shi)用雙臂(bei)電(dian)(dian)(dian)橋測(ce)出電(dian)(dian)(dian)纜芯線(xian)(xian)的(de)直流電(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)(zhi)，再(zai)準(zhun)確測(ce)量電(dian)(dian)(dian)纜實際(ji)長度(du)，按照電(dian)(dian)(dian)纜長度(du)與(yu)電(dian)(dian)(dian)阻(zu)(zu)(zu)的(de)正比例關(guan)系，計算出電(dian)(dian)(dian)纜故障點。該(gai)方(fang)法(fa)對(dui)于電(dian)(dian)(dian)纜芯線(xian)(xian)間(jian)(jian)直接(jie)短(duan)路或短(duan)路點接(jie)觸(chu)電(dian)(dian)(dian)阻(zu)(zu)(zu)小于1Ω的(de)故障，判斷誤差(cha)一般不(bu)大(da)于3m，對(dui)于故障點接(jie)觸(chu)電(dian)(dian)(dian)阻(zu)(zu)(zu)大(da)于1Ω的(de)故障，可采(cai)用加高電(dian)(dian)(dian)壓燒穿的(de)方(fang)法(fa)使(shi)電(dian)(dian)(dian)阻(zu)(zu)(zu)降(jiang)至1Ω以下，再(zai)按此方(fang)法(fa)測(ce)量。測(ce)量電(dian)(dian)(dian)路時，首先(xian)測(ce)出芯線(xian)(xian)a與(yu)b之(zhi)間(jian)(jian)的(de)電(dian)(dian)(dian)阻(zu)(zu)(zu)R1，R1=2RX+R其(qi)中RX為(wei)a相或b相至電(dian)(dian)(dian)纜故障點的(de)一相電(dian)(dian)(dian)阻(zu)(zu)(zu)值(zhi)(zhi)，只為(wei)短(duan)接(jie)點的(de)接(jie)觸(chu)電(dian)(dian)(dian)阻(zu)(zu)(zu)。

　　再就電(dian)(dian)(dian)(dian)(dian)橋移到電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)的(de)(de)另一端，測(ce)出a1與(yu)(yu)b1芯(xin)(xin)(xin)線間的(de)(de)直流(liu)電(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)R2，則(ze)R2=2R（L-X） R，R（L-X）為(wei)a1相(xiang)或(huo)b1相(xiang)芯(xin)(xin)(xin)線至電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)故(gu)(gu)障(zhang)點(dian)的(de)(de)一相(xiang)電(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)。測(ce)完(wan)R1與(yu)(yu)R2后(hou)，再按圖3所示(shi)(shi)電(dian)(dian)(dian)(dian)(dian)路(lu)將(jiang)b1與(yu)(yu)c1短路(lu)，測(ce)出b、c兩相(xiang)芯(xin)(xin)(xin)線間的(de)(de)直流(liu)電(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)，則(ze)該組(zu)織的(de)(de)1/2為(wei)每(mei)相(xiang)芯(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)，用(yong)RL表(biao)示(shi)(shi)，RL=RX R（L-X），由此可(ke)(ke)得出故(gu)(gu)障(zhang)點(dian)的(de)(de)接觸電(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)：R=R1 R2-2RL表(biao)，因此，故(gu)(gu)障(zhang)點(dian)兩側芯(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)(dian)阻(zu)值(zhi)(zhi)可(ke)(ke)用(yong)下式表(biao)示(shi)(shi)：RX=（R1-R）/2，R（L-X）=（R2-R）/2。RX、R（L-X）、RL三個數(shu)值(zhi)(zhi)確定后(hou)，按比(bi)例公式即可(ke)(ke)求(qiu)出故(gu)(gu)障(zhang)點(dian)距電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)端頭的(de)(de)距離X或(huo)（L-X）：X=（RX/RL）L，（L-X）=（R（L-2）在(zai)電(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)的(de)(de)末端在(zai)測(ce)量(liang)每(mei)相(xiang)芯(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)(dian)容電(dian)(dian)(dian)(dian)(dian)流(liu)Ia1、Ib2、Ic3的(de)(de)數(shu)值(zhi)(zhi)，以核對完(wan)好(hao)芯(xin)(xin)(xin)線與(yu)(yu)斷線芯(xin)(xin)(xin)線的(de)(de)電(dian)(dian)(dian)(dian)(dian)容之(zhi)比(bi)，初步(bu)可(ke)(ke)判(pan)斷出斷線距離近(jin)似點(dian)。

  根據電容量計算公式C=I/（2ΠfU）可知，正電壓U、頻率f不變時，C與I成正比。因為工頻電壓的f（頻率）不變，測量時只要保證施加電壓不變，電容電流之比即為電容量之比。設電纜全長為L，芯線斷線點距離為X，則Ia/Ic=L/X，X=（IC/Ia）L。測量過程中，只要保證電壓不變，電流表讀書準確，電纜總長度測量準確，其測定誤差比較小。

測聲法

　　所(suo)謂測聲(sheng)法就是(shi)根據故(gu)障(zhang)(zhang)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)的(de)聲(sheng)音(yin)(yin)進行查(cha)找(zhao)(zhao)，該(gai)方法對(dui)于(yu)高壓(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)芯線(xian)(xian)(xian)對(dui)絕緣(yuan)層閃絡(luo)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)較(jiao)為(wei)(wei)有效。此方法所(suo)用(yong)設備為(wei)(wei)直(zhi)流(liu)耐壓(ya)(ya)(ya)試驗(yan)(yan)機。其中(zhong)TB為(wei)(wei)高壓(ya)(ya)(ya)試驗(yan)(yan)變壓(ya)(ya)(ya)器，C為(wei)(wei)高壓(ya)(ya)(ya)電(dian)(dian)(dian)(dian)(dian)(dian)容器，VE為(wei)(wei)高壓(ya)(ya)(ya)整流(liu)硅(gui)堆，R為(wei)(wei)限流(liu)電(dian)(dian)(dian)(dian)(dian)(dian)阻，Q為(wei)(wei)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)球(qiu)間(jian)隙，L為(wei)(wei)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)芯線(xian)(xian)(xian)。當(dang)電(dian)(dian)(dian)(dian)(dian)(dian)容器C充電(dian)(dian)(dian)(dian)(dian)(dian)到一(yi)定(ding)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)值時，球(qiu)間(jian)隙對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)故(gu)障(zhang)(zhang)芯線(xian)(xian)(xian)放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)，在電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)故(gu)障(zhang)(zhang)處電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)芯線(xian)(xian)(xian)對(dui)絕緣(yuan)層放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)產(chan)生(sheng)“滋(zi)、滋(zi)”的(de)火花放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)聲(sheng)，對(dui)于(yu)明(ming)敷設電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)憑聽(ting)(ting)覺可(ke)直(zhi)接查(cha)找(zhao)(zhao)，若為(wei)(wei)地(di)埋電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)，則首(shou)先要確(que)定(ding)并標明(ming)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)走向。查(cha)找(zhao)(zhao)時，將(jiang)拾音(yin)(yin)器貼(tie)近地(di)面，沿電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)走向慢(man)(man)慢(man)(man)移(yi)動(dong)，當(dang)聽(ting)(ting)到“滋(zi)、滋(zi)”放(fang)電(dian)(dian)(dian)(dian)(dian)(dian)聲(sheng)大(da)時，該(gai)處即為(wei)(wei)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)故(gu)障(zhang)(zhang)點(dian)。使用(yong)該(gai)方法一(yi)定(ding)要注意安全，在試驗(yan)(yan)設備端和電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)末(mo)端應設專人(ren)監看。我公司生(sheng)產(chan)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)故(gu)障(zhang)(zhang)定(ding)位(wei)儀不僅(jin)可(ke)以(yi)測聲(sheng)，同時可(ke)以(yi)檢(jian)測磁信(xin)號(hao)(hao)，信(xin)號(hao)(hao)強度直(zhi)觀(guan)同步顯(xian)示(shi)，能夠更快更準的(de)定(ding)位(wei)電(dian)(dian)(dian)(dian)(dian)(dian)纜(lan)(lan)(lan)(lan)(lan)(lan)(lan)故(gu)障(zhang)(zhang)點(dian)。

零電位法

　　零(ling)電(dian)(dian)(dian)(dian)位(wei)法也就是電(dian)(dian)(dian)(dian)位(wei)比較(jiao)法，它適(shi)應(ying)(ying)于長(chang)度較(jiao)短的(de)(de)(de)電(dian)(dian)(dian)(dian)纜(lan)芯線對(dui)(dui)地故(gu)(gu)(gu)障(zhang)，應(ying)(ying)用此方法測量(liang)簡便準確，不需要精密儀器和(he)復雜計(ji)算。測量(liang)原(yuan)理如(ru)下(xia)：將電(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)(gu)障(zhang)芯線與(yu)等長(chang)的(de)(de)(de)比較(jiao)導線并聯，在b、c兩(liang)端(duan)(duan)加電(dian)(dian)(dian)(dian)壓VE時，相(xiang)當于在兩(liang)個并聯的(de)(de)(de)均勻電(dian)(dian)(dian)(dian)阻絲兩(liang)端(duan)(duan)接了電(dian)(dian)(dian)(dian)源，此時，一條電(dian)(dian)(dian)(dian)阻絲上(shang)(shang)的(de)(de)(de)任何(he)一點(dian)(dian)和(he)另(ling)一條電(dian)(dian)(dian)(dian)阻絲上(shang)(shang)的(de)(de)(de)對(dui)(dui)應(ying)(ying)點(dian)(dian)之間的(de)(de)(de)電(dian)(dian)(dian)(dian)位(wei)差(cha)必然為(wei)零(ling)，反之，電(dian)(dian)(dian)(dian)位(wei)差(cha)為(wei)零(ling)的(de)(de)(de)兩(liang)點(dian)(dian)必然是對(dui)(dui)應(ying)(ying)點(dian)(dian)。因為(wei)微伏表的(de)(de)(de)負(fu)極接地，與(yu)電(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)(gu)障(zhang)點(dian)(dian)等電(dian)(dian)(dian)(dian)位(wei)，所以，當微伏表的(de)(de)(de)正極在比較(jiao)導線上(shang)(shang)移動至指示值為(wei)零(ling)時的(de)(de)(de)點(dian)(dian)與(yu)電(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)(gu)障(zhang)點(dian)(dian)等電(dian)(dian)(dian)(dian)位(wei)，即電(dian)(dian)(dian)(dian)纜(lan)故(gu)(gu)(gu)障(zhang)點(dian)(dian)的(de)(de)(de)對(dui)(dui)應(ying)(ying)點(dian)(dian)。S為(wei)單相(xiang)閘刀開關，E為(wei)6E蓄(xu)電(dian)(dian)(dian)(dian)池或4節1號干電(dian)(dian)(dian)(dian)池，G為(wei)直流(liu)微伏表，測量(liang)步驟(zou)如(ru)下(xia)：

a）先在(zai)b和c相芯(xin)線上(shang)接上(shang)電池E，再在(zai)地面(mian)上(shang)敷設一(yi)根與故障電纜長度相等的比較導(dao)線S，該導(dao)線要(yao)用裸銅線或(huo)裸鋁線，其截(jie)面(mian)應相等，不能有中間接頭。

b）將微(wei)伏表的(de)負(fu)極接地(di)，正極接一根較長的(de)軟導線(xian)，導線(xian)另一端(duan)要求在敷設的(de)比較導線(xian)上(shang)滑動(dong)時(shi)能充分接觸。

c）合(he)上(shang)閘刀(dao)開關(guan)S，將軟導線的端頭在比較(jiao)導線上(shang)滑動，當微(wei)伏表指示為零時的位(wei)(wei)置即(ji)為電纜(lan)故障(zhang)點的位(wei)(wei)置。