用(yong)電力電纜故障(zhang)測試儀解決電力電纜故障(zhang)的方(fang)案(an)
A、原因分析（b）脈沖電壓法：
是利(li)用直流高(gao)壓或脈沖(chong)高(gao)壓信(xin)號(hao)擊穿電(dian)(dian)力(li)電(dian)(dian)纜的故(gu)障點(dian)(dian)，通過(guo)記錄放電(dian)(dian)電(dian)(dian)壓脈沖(chong)在測試點(dian)(dian)與(yu)故(gu)障點(dian)(dian)往返的時間計算出(chu)故(gu)障點(dian)(dian)的距(ju)離(li)。脈沖(chong)電(dian)(dian)壓法是直接(jie)利(li)用故(gu)障點(dian)(dian)擊穿產生的瞬間脈沖(chong)電(dian)(dian)壓信(xin)號(hao)。
（a）音頻(pin)感應(ying)法：
對于電(dian)力電(dian)纜的(de)短路故(gu)障(zhang)，由于無放電(dian)聲而不能采用聲磁法，只能采用音頻(pin)感應法對故(gu)障(zhang)點進行(xing)準確(que)定點。
（b）聲磁法：
使用脈沖(chong)高(gao)壓使電(dian)力(li)電(dian)纜(lan)故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)點(dian)(dian)擊(ji)穿放電(dian)，利(li)用電(dian)纜(lan)故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)間(jian)(jian)隙(xi)放電(dian)時(shi)(shi)產生(sheng)機(ji)械聲(sheng)(sheng)音(yin)(yin)(yin)對發(fa)生(sheng)高(gao)阻故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)和閃絡故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)的(de)電(dian)力(li)電(dian)纜(lan)定(ding)點(dian)(dian)。由于(yu)電(dian)力(li)電(dian)纜(lan)故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)的(de)狀(zhuang)態和類別不一、故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)損傷的(de)程度也不一樣、且電(dian)纜(lan)埋深或(huo)是否穿管(guan)等因素(su)都會反映到放電(dian)聲(sheng)(sheng)音(yin)(yin)(yin)的(de)大小(xiao)，即(ji)使在故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)點(dian)(dian)附近(jin)(jin)能聽到放電(dian)聲(sheng)(sheng)仍很難(nan)準(zhun)確定(ding)點(dian)(dian)。聲(sheng)(sheng)磁(ci)(ci)法是根(gen)據(ju)聲(sheng)(sheng)音(yin)(yin)(yin)信(xin)(xin)(xin)(xin)號(hao)(hao)與磁(ci)(ci)場(chang)(chang)信(xin)(xin)(xin)(xin)號(hao)(hao)傳(chuan)(chuan)(chuan)播(bo)速(su)度不一的(de)原(yuan)理，利(li)用儀器探(tan)頭撿出聲(sheng)(sheng)音(yin)(yin)(yin)信(xin)(xin)(xin)(xin)號(hao)(hao)和磁(ci)(ci)場(chang)(chang)信(xin)(xin)(xin)(xin)號(hao)(hao)的(de)時(shi)(shi)間(jian)(jian)差來確定(ding)準(zhun)確的(de)故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)點(dian)(dian)。聲(sheng)(sheng)音(yin)(yin)(yin)在電(dian)力(li)電(dian)纜(lan)周圍(wei)介質(zhi)中傳(chuan)(chuan)(chuan)播(bo)速(su)度大約為 500m/s左右，而磁(ci)(ci)場(chang)(chang)信(xin)(xin)(xin)(xin)號(hao)(hao)傳(chuan)(chuan)(chuan)播(bo)速(su)度幾乎(hu)接近(jin)(jin)于(yu)光速(su)——30萬km/s，從(cong)故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)點(dian)(dian)至(zhi)儀器探(tan)頭之間(jian)(jian)磁(ci)(ci)場(chang)(chang)信(xin)(xin)(xin)(xin)號(hao)(hao)傳(chuan)(chuan)(chuan)播(bo)的(de)時(shi)(shi)間(jian)(jian)可(ke)以(yi)忽略不計，以(yi)磁(ci)(ci)場(chang)(chang)信(xin)(xin)(xin)(xin)號(hao)(hao)觸(chu)發(fa)后開始記錄(lu)聲(sheng)(sheng)音(yin)(yin)(yin)信(xin)(xin)(xin)(xin)號(hao)(hao)，所以(yi)根(gen)據(ju)檢出的(de)聲(sheng)(sheng)音(yin)(yin)(yin)信(xin)(xin)(xin)(xin)號(hao)(hao)至(zhi)儀器探(tan)頭之間(jian)(jian)傳(chuan)(chuan)(chuan)播(bo)時(shi)(shi)間(jian)(jian)的(de)長短(duan)可(ke)以(yi)作為判(pan)斷電(dian)力(li)電(dian)纜(lan)故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)點(dian)(dian)的(de)遠近(jin)(jin)，檢測聲(sheng)(sheng)音(yin)(yin)(yin)傳(chuan)(chuan)(chuan)播(bo)時(shi)(shi)間(jian)(jian)zui短(duan)地點(dian)(dian)即(ji)為故(gu)(gu)(gu)障(zhang)(zhang)(zhang)(zhang)點(dian)(dian)。
