斷(duan)(duan)路器的(de)(de)操作過(guo)電(dian)(dian)(dian)壓(ya)是由于電(dian)(dian)(dian)路中(zhong)(zhong)存在(zai)(zai)(zai)電(dian)(dian)(dian)感(gan)電(dian)(dian)(dian)容儲(chu)能(neng)(neng)(neng)元件，在(zai)(zai)(zai)開(kai)(kai)(kai)關操作瞬(shun)間釋放出能(neng)(neng)(neng)量，在(zai)(zai)(zai)電(dian)(dian)(dian)路中(zhong)(zhong)產生電(dian)(dian)(dian)磁振蕩而(er)引發(fa)的(de)(de)。而(er)真空斷(duan)(duan)路器由于具有高速(su)滅弧(hu)能(neng)(neng)(neng)力，在(zai)(zai)(zai)切(qie)斷(duan)(duan)電(dian)(dian)(dian)路時，往(wang)往(wang)在(zai)(zai)(zai)電(dian)(dian)(dian)流過(guo)零前(qian)被強(qiang)行(xing)開(kai)(kai)(kai)斷(duan)(duan)，在(zai)(zai)(zai)斷(duan)(duan)弧(hu)瞬(shun)間儲(chu)藏在(zai)(zai)(zai)負(fu)載(zai)內的(de)(de)電(dian)(dian)(dian)感(gan)與電(dian)(dian)(dian)容之間的(de)(de)電(dian)(dian)(dian)磁能(neng)(neng)(neng)量轉換將在(zai)(zai)(zai)負(fu)載(zai)上產生過(guo)電(dian)(dian)(dian)壓(ya)，這(zhe)(zhe)比一(yi)般斷(duan)(duan)路器要突出，尤其在(zai)(zai)(zai)最(zui)先斷(duan)(duan)開(kai)(kai)(kai)相觸(chu)頭(tou)間，有可能(neng)(neng)(neng)因過(guo)電(dian)(dian)(dian)壓(ya)引起電(dian)(dian)(dian)弧(hu)重燃(ran)，而(er)產生更(geng)大的(de)(de)過(guo)電(dian)(dian)(dian)壓(ya)。在(zai)(zai)(zai)感(gan)性(xing)(xing)負(fu)載(zai)中(zhong)(zhong)，這(zhe)(zhe)種過(guo)電(dian)(dian)(dian)壓(ya)幅值高，上升陡度快(kuai)，頻率也高，這(zhe)(zhe)無疑(yi)對電(dian)(dian)(dian)動機等感(gan)性(xing)(xing)負(fu)載(zai)的(de)(de)絕緣(yuan)是十分危(wei)險的(de)(de)，總之，真空斷(duan)(duan)路器不(bu)管出現(xian)那種過(guo)電(dian)(dian)(dian)壓(ya)都會對設(she)備不(bu)利，嚴重地威脅著安全生產運行(xing)。

真(zhen)空斷路器在接通和分斷電(dian)(dian)路時(shi)，都可(ke)能發生(sheng)(sheng)操作過(guo)電(dian)(dian)壓(ya)。真(zhen)空斷路器的觸(chu)頭(tou)合閘時(shi)一(yi)般存(cun)在不同(tong)程度的彈跳現象，因而發生(sheng)(sheng)過(guo)電(dian)(dian)壓(ya)。但(dan)接通電(dian)(dian)路時(shi)，觸(chu)頭(tou)間(jian)距隨(sui)時(shi)間(jian)增長很(hen)快消失，觸(chu)頭(tou)間(jian)出現的過(guo)渡電(dian)(dian)壓(ya)星下降(jiang)趨勢，因此，過(guo)電(dian)(dian)壓(ya)的峰值一(yi).般較(jiao)低，對設備沒(mei)有多大威脅(xie)。影(ying)響設備安全運行的主(zhu)要(yao)是(shi)斷開電(dian)(dian)路時(shi)產生(sheng)(sheng)的過(guo)電(dian)(dian)壓(ya)，即截流過(guo)壓(ya)、電(dian)(dian)弧重燃過(guo)電(dian)(dian)壓(ya)、三(san)相同(tong)時(shi)截流過(guo)電(dian)(dian)壓(ya)。.

由于在截流、重燃或三相同時斷開時等原因產生過電壓，造成設備損壞，且由于真空斷路器滅弧能力極強，開斷時引起的過電壓會造成高壓設備絕緣擊穿、回路設備故障甚至斷路器等損壞、高壓開關柜燒毀等事故發生。真空斷路器的操作過電壓是由于電路中存在電感、電容儲能器件,開關操作瞬間釋放能量在電路中產生電磁振蕩而實現的。真空斷路器操作過電壓的產生真空斷路器在開斷變壓器等感性負載時，產生的操作過電壓分為截流過電壓、三相同時截流過電壓和多次重燃過電壓。
一、氧化鋅避雷器（MOA）。
眾所周知，這種避雷器主要優點是具有非常優良的非線性伏安特性，續流小，殘壓低，體積小，重量輕，安裝方便。但傳統的無間隙MOA在運行中存在以下弊病:
1）熱老化問題;  
2）為降低放電后殘壓值，其持續運行電壓選擇偏低，當出現單相接地運行時其承受√3倍的相電壓，致使荷電率上升，易損壞甚; 　
3）沖(chong)擊(ji)放電(dian)電(dian)壓和(he)相(xiang)(xiang)間殘壓值(zhi)偏(pian)高(gao)，不利于保持設備的相(xiang)(xiang)間絕緣。針對以上問(wen)題，一些廠家已(yi)推出有帶間隙的氧(yang)化鋅(xin)避雷器(qi)，筆(bi)者認為(wei)在(zai)選用上應優先(xian)考慮。

1、帶(dai)串聯(lian)間隙(xi)的(de)MOA。這種避雷(lei)(lei)器與傳統的(de)閥式(shi)避雷(lei)(lei)器結構差不多或基(ji)本相同。由于氧化(hua)鋅(xin)閥片具(ju)有非(fei)常優良的(de)非(fei)線性伏安(an)特(te)性，續流(liu)非(fei)常小，一般在1mA以(yi)下，可以(yi)認為無續流(liu)，另外，由于有串聯(lian)間隙(xi)存(cun)在，在正常運行電(dian)壓下，氧化(hua)鋅(xin)可以(yi)不加考慮。另外這種MOA的(de)殘壓值較低，可用于電(dian)力變壓器等耐(nai)壓水平較高的(de)設備(bei)的(de)過(guo)電(dian)壓防護。

2、帶并(bing)聯(lian)(lian)間隙的(de)(de)MOA。帶并(bing)聯(lian)(lian)間隙的(de)(de)結構是將閥片分為主閥片RI和(he)(he)并(bing)聯(lian)(lian)閥片R2，R1和(he)(he)R2串聯(lian)(lian)，在R2上有并(bing)聯(lian)(lian)間隙G。在正常(chang)電(dian)(dian)壓(ya)下，G不放電(dian)(dian)，電(dian)(dian)壓(ya)加在R1和(he)(he)R2上，運行安全可(ke)靠，過電(dian)(dian)壓(ya)作用(yong)時，避雷器(qi)上的(de)(de)殘壓(ya)還未達(da)到技術條(tiao)件(jian)規定值之前，G放電(dian)(dian)，R2被(bei)短(duan)路，避雷器(qi)的(de)(de)殘壓(ya)完全由R1上的(de)(de)殘壓(ya)所(suo)決定，所(suo)以(yi)殘壓(ya)比(bi)(bi)較(jiao)低，保護(hu)性能也比(bi)(bi)較(jiao)好，用(yong)于(yu)保護(hu)電(dian)(dian)動(dong)機(ji)是適宜(yi)的(de)(de)。

3、保(bao)護旋轉電機用并聯間隙MOA與無間隙MOA的(de)參數比較: 

類別 型號 電機額定電壓 持續運行電壓 標稱電流下最大殘壓 比較
無間隙 Y3WD-7.6 6.3 4 19 >18.382
Y3WD-12.7 10.5 6.6 31 >29.694
有間隙 Y3BD-7.6 6.3 4 16.2 <18.382
Y3BD-12.7 10.5 6.6 26.4 <29.694
注(zhu): 高(gao)壓電機(ji)絕緣(yuan)耐壓試驗(yan)標(biao)準（峰值）: 18.382kV(Un=6.3kV),29.694kV(Un=10.5kV)

二、阻容保護器。

阻(zu)(zu)容(rong)(rong)保(bao)護(hu)器(qi)是一(yi)種保(bao)護(hu)效(xiao)(xiao)果較好的措施，只要(yao)阻(zu)(zu)容(rong)(rong)參(can)數(shu)選(xuan)(xuan)擇(ze)妥當，就(jiu)可(ke)降(jiang)(jiang)低恢復電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上升陡度，降(jiang)(jiang)低振蕩頻(pin)率，減少負載(zai)波(bo)阻(zu)(zu)抗(kang)，就(jiu)能有效(xiao)(xiao)降(jiang)(jiang)低過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)幅(fu)值(zhi)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)C的作(zuo)用(yong)，除可(ke)降(jiang)(jiang)低過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)幅(fu)值(zhi)外(wai)，主要(yao)用(yong)以減緩(huan)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)上升陡度，因為(wei)這(zhe)種過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)在(zai)極短時間(jian)(jian)內發生(sheng)，du/dt很大(da)(da)，容(rong)(rong)易造成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)機(ji)進線繞組匝(za)(za)間(jian)(jian)擊穿。所(suo)以要(yao)降(jiang)(jiang)低匝(za)(za)間(jian)(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)并使匝(za)(za)間(jian)(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)分布均(jun)勻(yun)。另外(wai)達到(dao)降(jiang)(jiang)低波(bo)阻(zu)(zu)抗(kang)，降(jiang)(jiang)低截流(liu)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)之目(mu)的。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)R則起(qi)消耗高頻(pin)振蕩電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能，抑止(zhi)截流(liu)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)幅(fu)值(zhi)的作(zuo)用(yong)。由(you)于(yu)負載(zai)等(deng)效(xiao)(xiao)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)感和(he)(he)開關(guan)的截流(liu)值(zhi)等(deng)參(can)數(shu)難以查找和(he)(he)實(shi)測(ce)，難以準確選(xuan)(xuan)擇(ze)阻(zu)(zu)容(rong)(rong)參(can)數(shu)。根據(ju)經驗，一(yi)般吸收電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)選(xuan)(xuan)0.1～0.3μF/相，吸收電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻(zu)(zu)選(xuan)(xuan)100～200Ω/相，功率以不小于(yu)100W為(wei)宜。但值(zhi)得(de)注意的是，如果R、C阻(zu)(zu)容(rong)(rong)參(can)數(shu)選(xuan)(xuan)擇(ze)不當，不但起(qi)不到(dao)保(bao)護(hu)作(zuo)用(yong)，反(fan)而會起(qi)消極作(zuo)用(yong)，甚至會導致(zhi)過(guo)(guo)(guo)(guo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)幅(fu)值(zhi)倍增，在(zai)小電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)接地系統(tong)中，單相接地短路因R——C保(bao)護(hu)器(qi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)容(rong)(rong)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)流(liu)太大(da)(da)而招(zhao)致(zhi)系統(tong)饋電(dian)(dian)(dian)(dian)(dian)(dian)(dian)回路跳閘(zha)。因此在(zai)選(xuan)(xuan)R——C電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)幅(fu)值(zhi)抑止(zhi)器(qi)時應謹慎小心(xin)。

為避(bi)免操(cao)作真空斷路器產生的過電壓，特別是相(xiang)間過電壓，通常采(cai)用氧(yang)化鋅避(bi)雷器、阻容吸收器、三相(xiang)組合式(shi)過電壓保(bao)護器來限制過電壓。采(cai)用哪一(yi)種過電壓保(bao)護設(she)備(bei)，都應滿足以下條(tiao)件(jian)。

第一，為(wei)能有效(xiao)地防止過(guo)高的(de)操(cao)作過(guo)電壓(ya)對(dui)電壓(ya)設備的(de)絕緣造成的(de)危害(hai)，過(guo)電壓(ya)保(bao)護設備的(de)保(bao)護水平應低于被保(bao)護對(dui)象(xiang)電氣(qi)設備的(de)絕緣沖擊耐壓(ya)水平。

第二，由(you)于(yu)電氣設(she)備(bei)的相(xiang)間絕緣水(shui)(shui)平與(yu)相(xiang)對地絕緣水(shui)(shui)平一致，因此過電壓保護(hu)設(she)備(bei)的相(xiang)間保護(hu)水(shui)(shui)平與(yu)相(xiang)對地保護(hu)水(shui)(shui)平- -致。

第三(san)，在正(zheng)常(chang)和單相接地(di)工況并考(kao)慮了電(dian)(dian)壓波(bo)動15%的情況下，過電(dian)(dian)壓保護設備自(zi)身應(ying)能安全(quan)可靠的運行。

綜上(shang)所述(shu)，對于操作過電(dian)壓(ya)若(ruo)采(cai)用(yong)避雷(lei)器保(bao)(bao)護方案，應優(you)先用(yong)帶有間隙(xi)的MOA，選帶有串聯間隙(xi)的MOA保(bao)(bao)護變(bian)。