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斷(duan)路器(qi)的(de)操作過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓是由(you)于電(dian)(dian)(dian)(dian)(dian)(dian)路中存(cun)在電(dian)(dian)(dian)(dian)(dian)(dian)感(gan)(gan)電(dian)(dian)(dian)(dian)(dian)(dian)容儲(chu)能(neng)(neng)元件，在開關(guan)操作瞬間(jian)釋放出(chu)能(neng)(neng)量(liang)，在電(dian)(dian)(dian)(dian)(dian)(dian)路中產生(sheng)(sheng)電(dian)(dian)(dian)(dian)(dian)(dian)磁振蕩(dang)而(er)引(yin)(yin)發(fa)的(de)。而(er)真空(kong)斷(duan)路器(qi)由(you)于具有(you)高速滅弧(hu)能(neng)(neng)力，在切斷(duan)電(dian)(dian)(dian)(dian)(dian)(dian)路時，往往在電(dian)(dian)(dian)(dian)(dian)(dian)流過(guo)零前(qian)被強行開斷(duan)，在斷(duan)弧(hu)瞬間(jian)儲(chu)藏在負(fu)載(zai)(zai)內(nei)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)感(gan)(gan)與電(dian)(dian)(dian)(dian)(dian)(dian)容之(zhi)間(jian)的(de)電(dian)(dian)(dian)(dian)(dian)(dian)磁能(neng)(neng)量(liang)轉換(huan)將在負(fu)載(zai)(zai)上產生(sheng)(sheng)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓，這比(bi)一般斷(duan)路器(qi)要，尤其在先斷(duan)開相觸頭(tou)間(jian)，有(you)可能(neng)(neng)因過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓引(yin)(yin)起電(dian)(dian)(dian)(dian)(dian)(dian)弧(hu)重(zhong)燃，而(er)產生(sheng)(sheng)更大的(de)過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓。在感(gan)(gan)性(xing)負(fu)載(zai)(zai)中，這種過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓幅值(zhi)高，上升陡度快(kuai)，頻(pin)率也高，這無疑(yi)對(dui)電(dian)(dian)(dian)(dian)(dian)(dian)動機等感(gan)(gan)性(xing)負(fu)載(zai)(zai)的(de)絕緣是十分危險的(de)，總之(zhi)，真空(kong)斷(duan)路器(qi)不(bu)管出(chu)現那種過(guo)電(dian)(dian)(dian)(dian)(dian)(dian)壓都(dou)會對(dui)設備(bei)不(bu)利，嚴重(zhong)地威脅著安全生(sheng)(sheng)產運行。

真(zhen)空斷路器(qi)在接通和分(fen)斷電(dian)(dian)(dian)路時(shi)(shi)，都可能發生操作(zuo)過(guo)電(dian)(dian)(dian)壓。真(zhen)空斷路器(qi)的(de)觸頭合閘時(shi)(shi)一般存在不同程(cheng)度的(de)彈跳現象，因(yin)而發生過(guo)電(dian)(dian)(dian)壓。但接通電(dian)(dian)(dian)路時(shi)(shi)，觸頭間距隨時(shi)(shi)間增長很(hen)快消失，觸頭間出現的(de)過(guo)渡電(dian)(dian)(dian)壓星下降趨(qu)勢，因(yin)此，過(guo)電(dian)(dian)(dian)壓的(de)峰(feng)值一.般較低，對(dui)設(she)備沒有多大(da)威脅(xie)。影響設(she)備安(an)全運行的(de)主要是斷開(kai)電(dian)(dian)(dian)路時(shi)(shi)產生的(de)過(guo)電(dian)(dian)(dian)壓，即截流(liu)過(guo)壓、電(dian)(dian)(dian)弧(hu)重(zhong)燃過(guo)電(dian)(dian)(dian)壓、三相同時(shi)(shi)截流(liu)過(guo)電(dian)(dian)(dian)壓。.

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)擊放電電壓和相(xiang)間殘(can)壓值偏高，不利(li)于保持設(she)備的相(xiang)間絕緣。針對以上問題，一些廠家已(yi)推出有(you)帶(dai)間隙的氧(yang)化鋅避雷器，筆者認為(wei)在選用上應(ying)優先考慮。

1、帶串(chuan)聯間隙的(de)MOA。這種避(bi)雷器(qi)與(yu)傳(chuan)統的(de)閥式避(bi)雷器(qi)結(jie)構(gou)差不(bu)多或(huo)基本相同(tong)。由于氧化鋅閥片具有非常(chang)優良的(de)非線性(xing)伏安特(te)性(xing)，續流非常(chang)小，一般在1mA以下，可以認為(wei)無(wu)續流，另外，由于有串(chuan)聯間隙存在，在正常(chang)運行電(dian)壓(ya)下，氧化鋅可以不(bu)加考慮。另外這種MOA的(de)殘壓(ya)值(zhi)較(jiao)低，可用于電(dian)力變壓(ya)器(qi)等耐(nai)壓(ya)水(shui)平較(jiao)高(gao)的(de)設備的(de)過電(dian)壓(ya)防護。

2、帶并聯(lian)間隙(xi)的(de)MOA。帶并聯(lian)間隙(xi)的(de)結構(gou)是將閥片分為主閥片RI和(he)并聯(lian)閥片R2，R1和(he)R2串聯(lian)，在(zai)R2上(shang)有(you)并聯(lian)間隙(xi)G。在(zai)正常電(dian)壓(ya)(ya)(ya)(ya)下，G不放電(dian)，電(dian)壓(ya)(ya)(ya)(ya)加(jia)在(zai)R1和(he)R2上(shang)，運行(xing)安全可靠，過電(dian)壓(ya)(ya)(ya)(ya)作用時，避(bi)雷器(qi)上(shang)的(de)殘(can)(can)壓(ya)(ya)(ya)(ya)還(huan)未達到技(ji)術條(tiao)件規定值之前，G放電(dian)，R2被(bei)短路(lu)，避(bi)雷器(qi)的(de)殘(can)(can)壓(ya)(ya)(ya)(ya)由R1上(shang)的(de)殘(can)(can)壓(ya)(ya)(ya)(ya)所決定，所以殘(can)(can)壓(ya)(ya)(ya)(ya)比(bi)較低，保護性能也比(bi)較好，用于保護電(dian)動機是適宜的(de)。

3、保護旋轉(zhuan)電(dian)機(ji)用并聯間隙MOA與(yu)無(wu)間隙MOA的參數(shu)比較(jiao): 

類別 型號 電機額定電壓 持續運行電壓 標稱電流下殘壓 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): 高壓(ya)電機絕緣耐壓(ya)試驗標(biao)準（峰值）: 18.382kV(Un=6.3kV),29.694kV(Un=10.5kV)

二、阻容保護器。

阻(zu)容(rong)(rong)(rong)保護(hu)器(qi)是一種(zhong)保護(hu)效果較好的(de)措(cuo)施，只要阻(zu)容(rong)(rong)(rong)參(can)數(shu)(shu)選(xuan)(xuan)擇(ze)妥當，就(jiu)可(ke)降(jiang)低(di)(di)恢(hui)復電(dian)(dian)(dian)(dian)壓(ya)(ya)上(shang)升(sheng)陡度(du)，降(jiang)低(di)(di)振蕩頻(pin)率，減少負(fu)載波阻(zu)抗，就(jiu)能(neng)有(you)效降(jiang)低(di)(di)過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)幅值。電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)C的(de)作(zuo)(zuo)用(yong)，除可(ke)降(jiang)低(di)(di)過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)幅值外，主要用(yong)以減緩(huan)過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)上(shang)升(sheng)陡度(du)，因(yin)為(wei)這種(zhong)過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)在(zai)短時間(jian)內發生，du/dt很大，容(rong)(rong)(rong)易造成電(dian)(dian)(dian)(dian)機進線繞組匝(za)間(jian)擊穿。所以要降(jiang)低(di)(di)匝(za)間(jian)電(dian)(dian)(dian)(dian)壓(ya)(ya)并(bing)使匝(za)間(jian)電(dian)(dian)(dian)(dian)壓(ya)(ya)分布均勻(yun)。另外達到降(jiang)低(di)(di)波阻(zu)抗，降(jiang)低(di)(di)截流(liu)過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)之(zhi)目的(de)。電(dian)(dian)(dian)(dian)阻(zu)R則起消耗高頻(pin)振蕩電(dian)(dian)(dian)(dian)能(neng)，抑止(zhi)截流(liu)過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)幅值的(de)作(zuo)(zuo)用(yong)。由(you)于負(fu)載等效電(dian)(dian)(dian)(dian)感(gan)和開關的(de)截流(liu)值等參(can)數(shu)(shu)難(nan)以查找和實測(ce)，難(nan)以準確選(xuan)(xuan)擇(ze)阻(zu)容(rong)(rong)(rong)參(can)數(shu)(shu)。根(gen)據(ju)經驗(yan)，一般吸收(shou)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)選(xuan)(xuan)0.1～0.3μF/相，吸收(shou)電(dian)(dian)(dian)(dian)阻(zu)選(xuan)(xuan)100～200Ω/相，功率以不小于100W為(wei)宜。但值得注意的(de)是，如果R、C阻(zu)容(rong)(rong)(rong)參(can)數(shu)(shu)選(xuan)(xuan)擇(ze)不當，不但起不到保護(hu)作(zuo)(zuo)用(yong)，反(fan)而會(hui)起消作(zuo)(zuo)用(yong)，甚至(zhi)會(hui)導(dao)致過(guo)電(dian)(dian)(dian)(dian)壓(ya)(ya)幅值倍增，在(zai)小電(dian)(dian)(dian)(dian)流(liu)接地系統(tong)中，單相接地短路(lu)因(yin)R——C保護(hu)器(qi)電(dian)(dian)(dian)(dian)容(rong)(rong)(rong)電(dian)(dian)(dian)(dian)流(liu)太大而招致系統(tong)饋電(dian)(dian)(dian)(dian)回路(lu)跳閘。因(yin)此在(zai)選(xuan)(xuan)R——C電(dian)(dian)(dian)(dian)壓(ya)(ya)幅值抑止(zhi)器(qi)時應(ying)謹慎(shen)小心(xin)。

為避免(mian)操作真空(kong)斷路器(qi)產(chan)生(sheng)的(de)過(guo)(guo)(guo)電(dian)壓(ya)(ya)，特別是相間過(guo)(guo)(guo)電(dian)壓(ya)(ya)，通常采(cai)用氧化鋅(xin)避雷器(qi)、阻容吸(xi)收器(qi)、三相組(zu)合(he)式過(guo)(guo)(guo)電(dian)壓(ya)(ya)保護器(qi)來限制過(guo)(guo)(guo)電(dian)壓(ya)(ya)。采(cai)用哪一(yi)種過(guo)(guo)(guo)電(dian)壓(ya)(ya)保護設備，都應(ying)滿足以下條件。

，為能有效地防止過高(gao)的(de)操作(zuo)過電壓對(dui)電壓設(she)(she)備的(de)絕緣造成的(de)危害，過電壓保護(hu)設(she)(she)備的(de)保護(hu)水平應低于被保護(hu)對(dui)象電氣(qi)設(she)(she)備的(de)絕緣沖擊耐壓水平。

第二，由于電(dian)氣(qi)設(she)備的(de)相間絕緣水(shui)(shui)平(ping)與(yu)相對地絕緣水(shui)(shui)平(ping)一致，因此(ci)過電(dian)壓保(bao)護(hu)(hu)設(she)備的(de)相間保(bao)護(hu)(hu)水(shui)(shui)平(ping)與(yu)相對地保(bao)護(hu)(hu)水(shui)(shui)平(ping)- -致。

第三，在正常和單相接地工(gong)況并考(kao)慮了(le)電壓波(bo)動15%的情況下，過電壓保(bao)護設備自身應能安全可靠的運(yun)行。

綜上所述，對于(yu)操作過電壓若采用避(bi)雷器保(bao)護(hu)方案(an)，應(ying)優先用帶(dai)有(you)間隙的MOA，選帶(dai)有(you)串聯間隙的MOA保(bao)護(hu)變。