浪(lang)涌保護器中的重要(yao)組成部分(fen)就是(shi)氣(qi)體(ti)(ti)放(fang)(fang)(fang)電管。氣(qi)體(ti)(ti)放(fang)(fang)(fang)電管是(shi)一種(zhong)用(yong)陶瓷或玻璃封(feng)裝、內充低壓(ya)惰性氣(qi)體(ti)(ti)的放(fang)(fang)(fang)電間隙(xi)。在(zai)正常工作時，間隙(xi)呈高(gao)阻抗。當加在(zai)間隙(xi)上的浪(lang)涌電壓(ya)超過其(qi)放(fang)(fang)(fang)電電壓(ya)時，間隙(xi)擊穿，從而(er)起(qi)到限制(zhi)過電壓(ya)的作用(yong)。浪(lang)涌過后氣(qi)體(ti)(ti)放(fang)(fang)(fang)電管應(ying)能恢(hui)復(fu)到高(gao)阻抗狀態。

【鈞(jun)和電(dian)子?浪(lang)涌(yong)(yong)保護器(qi)】今天重點(dian)介(jie)紹一下(xia)浪(lang)涌(yong)(yong)保護器(qi)中選配(pei)的氣體放電(dian)管(guan)的主要參數：

一、靜(jing)態(tai)放電電壓

靜(jing)態放電(dian)(dian)(dian)電(dian)(dian)(dian)壓是指在直流(liu)電(dian)(dian)(dian)壓作(zuo)用下(xia)放電(dian)(dian)(dian)管開始放電(dian)(dian)(dian)的(de)電(dian)(dian)(dian)壓。放電(dian)(dian)(dian)管靜(jing)態放電(dian)(dian)(dian)電(dian)(dian)(dian)壓的(de)高低，決定于極間距離與管內氣(qi)體壓力的(de)乘積，而且(qie)放電(dian)(dian)(dian)電(dian)(dian)(dian)壓存在一個最低值。

由于放(fang)電(dian)所需的(de)有效(xiao)電(dian)子的(de)出(chu)現(xian)以(yi)及有效(xiao)電(dian)子發(fa)展(zhan)為(wei)導致擊穿的(de)電(dian)子雪(xue)崩需要時(shi)間，所以(yi)作(zuo)用在(zai)放(fang)電(dian)管上(shang)的(de)電(dian)壓達到(dao)靜(jing)態放(fang)電(dian)電(dian)壓的(de)時(shi)間與放(fang)電(dian)管導通的(de)時(shi)間之(zhi)間，存在(zai)一(yi)定的(de)時(shi)延(yan)。這一(yi)時(shi)延(yan)稱為(wei)擊穿時(shi)延(yan)，也稱為(wei)響應時(shi)間。

二、沖擊放電電壓

沖(chong)(chong)擊放(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)(ya)是指放(fang)(fang)電(dian)(dian)(dian)(dian)管在(zai)沖(chong)(chong)擊電(dian)(dian)(dian)(dian)壓(ya)(ya)作用(yong)下導通(tong)時，作用(yong)在(zai)放(fang)(fang)電(dian)(dian)(dian)(dian)管兩端的電(dian)(dian)(dian)(dian)壓(ya)(ya)。由(you)于放(fang)(fang)電(dian)(dian)(dian)(dian)存在(zai)時延，而終極(ji)電(dian)(dian)(dian)(dian)壓(ya)(ya)是隨時間(jian)做迅速變化的，在(zai)放(fang)(fang)電(dian)(dian)(dian)(dian)時延期間(jian)沖(chong)(chong)擊電(dian)(dian)(dian)(dian)壓(ya)(ya)還在(zai)上升(sheng)，所(suo)以放(fang)(fang)電(dian)(dian)(dian)(dian)管的沖(chong)(chong)擊放(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)(ya)要比其靜(jing)態放(fang)(fang)電(dian)(dian)(dian)(dian)電(dian)(dian)(dian)(dian)壓(ya)(ya)高。沖(chong)(chong)擊電(dian)(dian)(dian)(dian)壓(ya)(ya)波的陡度越(yue)大，兩者的差(cha)距就越(yue)大。

工程(cheng)上(shang)常用(yong)放(fang)電(dian)管擊(ji)(ji)(ji)穿(chuan)器件出現的沖擊(ji)(ji)(ji)電(dian)壓(ya)(ya)的最大值(zhi)和(he)擊(ji)(ji)(ji)穿(chuan)時間的關系來表征放(fang)電(dian)管在(zai)沖擊(ji)(ji)(ji)電(dian)壓(ya)(ya)作用(yong)下(xia)的放(fang)電(dian)特(te)性(xing)，即伏(fu)(fu)秒特(te)性(xing)。科學實驗表明，伏(fu)(fu)秒特(te)性(xing)在(zai)絕(jue)緣組合中起(qi)著重要的作用(yong)，放(fang)電(dian)管的伏(fu)(fu)秒特(te)性(xing)越(yue)平坦越(yue)容易實現絕(jue)緣配合。

三、工頻耐(nai)流能(neng)力

工頻耐(nai)(nai)流(liu)能(neng)力是指放(fang)電(dian)管所能(neng)通(tong)過的(de)(de)(de)最大電(dian)流(liu)值。對給(gei)定的(de)(de)(de)放(fang)電(dian)管，通(tong)過電(dian)流(liu)的(de)(de)(de)時間越長，所能(neng)耐(nai)(nai)受的(de)(de)(de)電(dian)流(liu)就(jiu)越小。玻(bo)璃(li)放(fang)電(dian)管的(de)(de)(de)工頻耐(nai)(nai)流(liu)能(neng)力較小，陶瓷放(fang)電(dian)管的(de)(de)(de)工頻耐(nai)(nai)流(liu)能(neng)力則(ze)高得多。

四、沖(chong)擊(ji)耐流能(neng)力

沖擊耐(nai)流(liu)(liu)能力是指(zhi)放(fang)電(dian)管耐(nai)受脈沖電(dian)流(liu)(liu)的能力。通常用耐(nai)受規定波型(xing)和幅值的脈沖電(dian)流(liu)(liu)次(ci)數來標識。對于20/40μs的電(dian)流(liu)(liu)波，玻璃放(fang)電(dian)管的一次(ci)沖擊耐(nai)流(liu)(liu)能力最大可達(da)3kA，陶(tao)瓷放(fang)電(dian)管可達(da)到(dao)20kA以上。

五(wu)、熄弧(hu)時間

熄弧時間是指沖擊過后，放電(dian)管(guan)恢復到(dao)正常絕緣(yuan)所需要的時間，其值越小越好。

氣體放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管有二電(dian)(dian)(dian)(dian)(dian)極和(he)三電(dian)(dian)(dian)(dian)(dian)極兩種結構。二電(dian)(dian)(dian)(dian)(dian)極放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管的(de)缺點是(shi)分別接(jie)在一(yi)個回(hui)路(lu)的(de)兩根導線(xian)和(he)地(di)(di)(di)(di)間(jian)，用來限制(zhi)導線(xian)對(dui)(dui)地(di)(di)(di)(di)過電(dian)(dian)(dian)(dian)(dian)壓的(de)兩只二極放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管，有時會出現不同時放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)的(de)現象，使兩根導線(xian)之間(jian)存在電(dian)(dian)(dian)(dian)(dian)位差(cha)。為了有效限制(zhi)差(cha)模過電(dian)(dian)(dian)(dian)(dian)壓，必須再在導線(xian)間(jian)加裝放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管。三極放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管是(shi)由二極放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管合(he)并在一(yi)起構成的(de)，其中間(jian)的(de)一(yi)個電(dian)(dian)(dian)(dian)(dian)極接(jie)地(di)(di)(di)(di)，另兩電(dian)(dian)(dian)(dian)(dian)極分別接(jie)在回(hui)路(lu)的(de)兩根導線(xian)上。三級放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)管的(de)優點是(shi)會產(chan)生競爭放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)，利(li)用先對(dui)(dui)接(jie)地(di)(di)(di)(di)極放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)的(de)電(dian)(dian)(dian)(dian)(dian)極所產(chan)生的(de)電(dian)(dian)(dian)(dian)(dian)弧照射另一(yi)未(wei)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)的(de)間(jian)隙，促(cu)使未(wei)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)的(de)間(jian)隙提(ti)前產(chan)生點火(huo)電(dian)(dian)(dian)(dian)(dian)子(zi)，使之在極端時間(jian)內對(dui)(dui)地(di)(di)(di)(di)放(fang)(fang)(fang)(fang)(fang)電(dian)(dian)(dian)(dian)(dian)，從(cong)而有效地(di)(di)(di)(di)限制(zhi)差(cha)模過電(dian)(dian)(dian)(dian)(dian)壓。

氣體放電(dian)管通(tong)流容量大、絕緣電(dian)阻高、漏(lou)電(dian)流小、極間電(dian)容小，但(dan)其(qi)動作電(dian)壓較高，相應時(shi)間慢，而(er)且動作后會出現續流，不易關斷(duan)，所以通(tong)常適用于電(dian)話線及(ji)高至50MHz信號(hao)的初級保護。