1、地電(dian)波檢測(ce)
在(zai)高壓開(kai)關(guan)柜(ju)絕緣(yuan)層中發生(sheng)(sheng)局部放電(dian)(dian)時會(hui)產(chan)生(sheng)(sheng)電(dian)(dian)磁波(bo)(bo),而(er)開(kai)關(guan)柜(ju)的(de)(de)金(jin)屬(shu)外(wai)(wai)殼(ke)(ke)會(hui)將這種電(dian)(dian)磁波(bo)(bo)屏蔽掉一大(da)部分,不過(guo)仍有小部分會(hui)通過(guo)金(jin)屬(shu)殼(ke)(ke)體(ti)的(de)(de)接(jie)縫或(huo)者(zhe)氣體(ti)絕緣(yuan)開(kai)關(guan)襯墊(dian)傳(chuan)播出去,而(er)且還會(hui)產(chan)生(sheng)(sheng)一個(ge)地(di)電(dian)(dian)波(bo)(bo)通過(guo)設備金(jin)屬(shu)殼(ke)(ke)體(ti)外(wai)(wai)表面傳(chuan)向地(di)下。地(di)電(dian)(dian)波(bo)(bo)的(de)(de)范圍(wei)通常在(zai)幾(ji)毫伏直至幾(ji)伏中間,而(er)且上升時間內有幾(ji)個(ge)納秒(miao)。可以(yi)將探頭(tou)設置(zhi)于工作狀(zhuang)態中的(de)(de)開(kai)關(guan)柜(ju)的(de)(de)外(wai)(wai)表面,對局部放電(dian)(dian)活(huo)動進行檢測(ce)。
2、超聲波檢測
其(qi)實(shi)超聲(sheng)(sheng)波(bo)檢(jian)測屬(shu)于機械振動波(bo)的(de)(de)(de)一種,基于能(neng)(neng)(neng)量(liang)(liang)(liang)的(de)(de)(de)角度而(er)言,局部(bu)放(fang)(fang)(fang)電(dian)的(de)(de)(de)過(guo)(guo)程即(ji)為(wei)能(neng)(neng)(neng)量(liang)(liang)(liang)瞬時爆(bao)發的(de)(de)(de)過(guo)(guo)程,電(dian)能(neng)(neng)(neng)通(tong)(tong)過(guo)(guo)聲(sheng)(sheng)能(neng)(neng)(neng)、光能(neng)(neng)(neng)、熱(re)能(neng)(neng)(neng)以及電(dian)磁能(neng)(neng)(neng)的(de)(de)(de)形式釋(shi)放(fang)(fang)(fang)出(chu)去,電(dian)氣擊穿發生在空(kong)氣間(jian)隙,瞬間(jian)就可以完成放(fang)(fang)(fang)電(dian),此時電(dian)能(neng)(neng)(neng)也會(hui)在一瞬間(jian)轉(zhuan)化為(wei)熱(re)能(neng)(neng)(neng),放(fang)(fang)(fang)電(dian)中心的(de)(de)(de)氣體(ti)受(shou)到熱(re)能(neng)(neng)(neng)的(de)(de)(de)作用會(hui)發生膨脹,通(tong)(tong)過(guo)(guo)聲(sheng)(sheng)波(bo)向外傳播(bo),傳播(bo)區(qu)域內氣體(ti)被加(jia)熱(re)后形成一個等(deng)(deng)溫(wen)區(qu),其(qi)溫(wen)度超出(chu)環境溫(wen)度;等(deng)(deng)到這些氣體(ti)冷卻后開始(shi)收縮(suo),則會(hui)產生后續波(bo),后續波(bo)的(de)(de)(de)頻(pin)(pin)率(lv)以及強度均比較低(di),包含(han)各種頻(pin)(pin)率(lv)分量(liang)(liang)(liang),有很(hen)寬的(de)(de)(de)頻(pin)(pin)帶,超聲(sheng)(sheng)波(bo)的(de)(de)(de)頻(pin)(pin)率(lv)大(da)于20kHz。因為(wei)局部(bu)放(fang)(fang)(fang)電(dian)的(de)(de)(de)區(qu)域相對(dui)較小,所以局放(fang)(fang)(fang)聲(sheng)(sheng)源即(ji)為(wei)點聲(sheng)(sheng)源。
3、超高頻檢測法
時間(jian)變化過(guo)(guo)程中,局(ju)部放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)所產生(sheng)的(de)(de)電(dian)(dian)(dian)(dian)磁振動會(hui)產生(sheng)電(dian)(dian)(dian)(dian)磁波,在固氣(qi)與(yu)氣(qi)體介質中,局(ju)部放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)脈沖會(hui)發生(sheng)非常豐(feng)富(fu)的(de)(de)電(dian)(dian)(dian)(dian)磁波超(chao)高頻分(fen)量。在實際應用過(guo)(guo)程中,局(ju)放(fang)(fang)(fang)(fang)信(xin)號(hao)的(de)(de)檢測可(ke)以利用兩(liang)個探(tan)(tan)頭(tou)來(lai)進行,將探(tan)(tan)頭(tou)檢測到信(xin)號(hao)的(de)(de)時間(jian)順(shun)序作為判(pan)斷(duan)依據,放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)源的(de)(de)距離較(jiao)近,就會(hui)被先(xian)檢測到;探(tan)(tan)頭(tou)位置不斷(duan)變化,可(ke)以將放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)源的(de)(de)大(da)致位置逐步判(pan)斷(duan)出(chu)來(lai)。或者通過(guo)(guo)多個探(tan)(tan)頭(tou),將探(tan)(tan)頭(tou)檢測局(ju)放(fang)(fang)(fang)(fang)信(xin)號(hao)的(de)(de)時間(jian)差列方程組(zu),可(ke)以求出(chu)放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)源的(de)(de)三維空間(jian)坐標,最終確(que)定放(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)源。該方法的(de)(de)靈(ling)敏度相對較(jiao)高,且(qie)具備較(jiao)強的(de)(de)抗干(gan)擾能力。