一、真空滅弧室由什么組成
真(zhen)空滅弧室是中(zhong)高壓電(dian)力開關的核心部(bu)件,它(ta)的結構(gou)一般包括以下幾個部(bu)分(fen):
1、氣密絕緣系統
由玻(bo)璃(li)或(huo)陶(tao)瓷制(zhi)成的氣(qi)(qi)密(mi)絕緣(yuan)外殼、動(dong)(dong)端蓋(gai)板(ban)、定端蓋(gai)板(ban),不(bu)銹(xiu)鋼波紋(wen)管組成了氣(qi)(qi)密(mi)絕緣(yuan)系(xi)統(tong)。為了保證玻(bo)璃(li)、陶(tao)瓷與(yu)金(jin)屬之間(jian)有良好的氣(qi)(qi)密(mi)性,除(chu)了封(feng)接時要(yao)有嚴格的操(cao)作(zuo)工(gong)藝外,還要(yao)求材料本身的透氣(qi)(qi)性盡量(liang)小(xiao)和內(nei)部放氣(qi)(qi)量(liang)限制(zhi)到(dao)極小(xiao)值(zhi)。不(bu)銹(xiu)鋼波紋(wen)管的作(zuo)用(yong)不(bu)僅能將真空滅弧室內(nei)部的真空狀態與(yu)外部的大氣(qi)(qi)狀態隔離(li)開來,而且能使動(dong)(dong)觸頭連同(tong)動(dong)(dong)導電桿在(zai)規定的范圍內(nei)運動(dong)(dong),以完成真空開關的閉(bi)合與(yu)分斷操(cao)作(zuo)。
2、導電系統
定(ding)導(dao)(dao)電(dian)(dian)(dian)桿、定(ding)跑(pao)(pao)弧面、定(ding)觸頭(tou)、動(dong)(dong)(dong)(dong)觸頭(tou)、動(dong)(dong)(dong)(dong)跑(pao)(pao)弧面、動(dong)(dong)(dong)(dong)導(dao)(dao)電(dian)(dian)(dian)桿構成了滅(mie)弧室的(de)(de)導(dao)(dao)電(dian)(dian)(dian)系統。其中定(ding)導(dao)(dao)電(dian)(dian)(dian)桿、定(ding)跑(pao)(pao)弧面、定(ding)觸頭(tou)合(he)稱定(ding)電(dian)(dian)(dian)極(ji),動(dong)(dong)(dong)(dong)觸頭(tou)、動(dong)(dong)(dong)(dong)跑(pao)(pao)弧面、動(dong)(dong)(dong)(dong)導(dao)(dao)電(dian)(dian)(dian)桿合(he)稱動(dong)(dong)(dong)(dong)電(dian)(dian)(dian)極(ji),由真空(kong)(kong)滅(mie)弧室組裝成的(de)(de)真空(kong)(kong)斷路器,真空(kong)(kong)負(fu)荷開(kai)關和真空(kong)(kong)接(jie)觸器合(he)閘時,操動(dong)(dong)(dong)(dong)機構通(tong)過動(dong)(dong)(dong)(dong)導(dao)(dao)電(dian)(dian)(dian)桿的(de)(de)運動(dong)(dong)(dong)(dong),使(shi)兩觸頭(tou)閉合(he),完(wan)成了電(dian)(dian)(dian)路的(de)(de)接(jie)通(tong)。
為了使兩(liang)(liang)觸(chu)(chu)頭(tou)(tou)間(jian)(jian)的接(jie)觸(chu)(chu)電(dian)(dian)阻盡(jin)可能減小且(qie)保(bao)持穩定和滅(mie)(mie)弧室(shi)承受動穩定電(dian)(dian)流(liu)(liu)時有(you)(you)良好的機械強度,真(zhen)空開(kai)關(guan)在(zai)動導電(dian)(dian)桿一端設置有(you)(you)導向(xiang)套,并(bing)使用(yong)一組壓縮彈(dan)簧,使兩(liang)(liang)觸(chu)(chu)頭(tou)(tou)間(jian)(jian)保(bao)持有(you)(you)一個額定壓力。當真(zhen)空開(kai)關(guan)分斷(duan)(duan)電(dian)(dian)流(liu)(liu)時,滅(mie)(mie)弧室(shi)兩(liang)(liang)觸(chu)(chu)頭(tou)(tou)分離并(bing)在(zai)其間(jian)(jian)產生電(dian)(dian)弧,直至電(dian)(dian)流(liu)(liu)自然(ran)過零時電(dian)(dian)弧熄滅(mie)(mie),便完(wan)成(cheng)了電(dian)(dian)路的開(kai)斷(duan)(duan)。
3、屏蔽系統
真空(kong)滅弧(hu)室的(de)屏(ping)蔽系統主(zhu)(zhu)要由(you)屏(ping)蔽筒,屏(ping)蔽罩和其他零件組(zu)成。屏(ping)蔽系統的(de)主(zhu)(zhu)要作用(yong)是(shi):
(1)防止觸頭(tou)在燃弧(hu)過(guo)程中產生大量(liang)的(de)(de)金屬蒸(zheng)汽和液滴噴(pen)濺,污染絕(jue)緣外殼的(de)(de)內壁,避(bi)免造成真空滅弧(hu)室外殼的(de)(de)絕(jue)緣強度下降或產生閃絡。
(2)改善真(zhen)空(kong)(kong)滅弧室(shi)內部(bu)的電場分布,有利于真(zhen)空(kong)(kong)滅弧室(shi)絕緣外殼的小(xiao)型(xing)(xing)化(hua),尤其(qi)是對(dui)于高電壓的真(zhen)空(kong)(kong)滅弧室(shi)小(xiao)型(xing)(xing)化(hua)有顯著效果。
(3)吸(xi)(xi)收(shou)(shou)一(yi)部(bu)分電(dian)弧(hu)(hu)(hu)(hu)能量(liang)(liang),冷凝電(dian)弧(hu)(hu)(hu)(hu)生(sheng)(sheng)成物(wu)(wu)。特(te)別是(shi)真空(kong)滅弧(hu)(hu)(hu)(hu)室在開斷(duan)短路電(dian)流時,電(dian)弧(hu)(hu)(hu)(hu)所(suo)產生(sheng)(sheng)的(de)(de)熱能大(da)(da)部(bu)分被屏蔽系統所(suo)吸(xi)(xi)收(shou)(shou),有利于(yu)提高觸頭間(jian)的(de)(de)介(jie)質恢復強(qiang)度。屏蔽系統吸(xi)(xi)收(shou)(shou)電(dian)弧(hu)(hu)(hu)(hu)生(sheng)(sheng)成物(wu)(wu)的(de)(de)量(liang)(liang)越大(da)(da),說明他(ta)吸(xi)(xi)收(shou)(shou)的(de)(de)能量(liang)(liang)也越大(da)(da),這對增加真空(kong)滅弧(hu)(hu)(hu)(hu)室的(de)(de)開斷(duan)容量(liang)(liang)起良好作用。
4、觸頭系統
觸(chu)頭是導(dao)電產(chan)生電弧(hu)、熄(xi)滅(mie)電弧(hu)的(de)部位,對材料的(de)要(yao)(yao)求很(hen)高。觸(chu)頭材料主(zhu)要(yao)(yao)有(you)銅(tong)鉍合(he)(he)金(jin)、銅(tong)鉻合(he)(he)金(jin)、銅(tong)鎢合(he)(he)金(jin)等幾種,目前斷(duan)路器用真(zhen)空滅(mie)弧(hu)室大量使用的(de)主(zhu)要(yao)(yao)是銅(tong)鉻合(he)(he)金(jin)。
觸(chu)頭結構的作用主要(yao)是在真空滅(mie)弧室(shi)分(fen)斷短(duan)路電流時,在觸(chu)頭間(jian)形(xing)成(cheng)橫(heng)向磁場(chang)或縱向磁場(chang),從而限制(zhi)觸(chu)頭表(biao)面(mian)陽(yang)極斑(ban)點(dian)的形(xing)成(cheng),提(ti)高滅(mie)弧室(shi)的分(fen)斷能力。
5、波紋管
真(zhen)空(kong)(kong)滅(mie)(mie)弧(hu)室的(de)波紋管主要擔負保(bao)證動電(dian)極在一定范(fan)圍內運動和(he)長期保(bao)持高真(zhen)空(kong)(kong)的(de)功能,并保(bao)證真(zhen)空(kong)(kong)滅(mie)(mie)弧(hu)室具有很(hen)高的(de)機械壽命。
真空滅弧室的波(bo)(bo)紋(wen)管(guan)(guan)是由厚度為0.1~0.2mm的不銹鋼制(zhi)成的薄壁(bi)元件。真空開(kai)關在(zai)分合過程中,滅弧室波(bo)(bo)紋(wen)管(guan)(guan)受伸縮作用,波(bo)(bo)紋(wen)管(guan)(guan)截面上受變應(ying)力作用,所以(yi)波(bo)(bo)紋(wen)管(guan)(guan)的壽命應(ying)根據反復伸縮量(liang)和使(shi)用壓力來確定(ding)。
二、真空滅弧室的工作原理是什么
真空滅弧室主要由一對密封在真空中的電極構成,利用真空絕緣的特點,真空滅弧室能夠實現電路電流的導(dao)通和(he)開斷功能。其基本工(gong)作原理是:
在(zai)分斷(duan)電流時(shi),首先動(dong)定(ding)(ding)觸(chu)頭分離(li)致使金(jin)屬(shu)橋爆炸(zha),從而(er)(er)產(chan)生絕緣的(de)真空電弧,并(bing)在(zai)自(zi)生磁場的(de)作用(yong)下,保持電弧的(de)擴(kuo)散形(xing)態(tai),以保證觸(chu)頭的(de)燃弧面能(neng)(neng)夠均勻燒蝕,然后在(zai)電流過零時(shi)電弧熄滅,動(dong)定(ding)(ding)觸(chu)頭的(de)熔斷(duan)處會冷卻凝固,與此同時(shi),觸(chu)頭之間的(de)等離(li)子體(ti)也將迅速恢復(fu),從而(er)(er)保證觸(chu)頭能(neng)(neng)夠承受(shou)快(kuai)速升(sheng)高的(de)恢復(fu)電壓(ya),實(shi)現電流的(de)開斷(duan)。