新聞動態
試驗變壓器之擊穿試驗的方法分析
試驗變壓器之擊穿試驗的方法分析
1、測試方法現狀
目(mu)前(qian)(qian)國(guo)內電(dian)(dian)(dian)力行業(ye)，尤其是供電(dian)(dian)(dian)系(xi)統(tong)和安裝系(xi)統(tong)， 目(mu)前(qian)(qian)關于絕(jue)(jue)(jue)緣油(you)(you)擊(ji)穿電(dian)(dian)(dian)壓(ya)測試(shi)(shi)(shi)方(fang)(fang)法(fa)(fa)的(de)(de)標準比較(jiao)常用(yong)的(de)(de)有GB/T507—1986《電(dian)(dian)(dian)氣(qi)(qi)用(yong)油(you)(you)絕(jue)(jue)(jue)緣強度(du)測定法(fa)(fa)》和DL/T429—1991《電(dian)(dian)(dian)力系(xi)統(tong)油(you)(you)質試(shi)(shi)(shi)驗方(fang)(fang)法(fa)(fa)》，其中(zhong)GB/T507—1986主(zhu)要參照IEC156《絕(jue)(jue)(jue)緣油(you)(you)電(dian)(dian)(dian)氣(qi)(qi)強度(du)測定方(fang)(fang)法(fa)(fa)》制(zhi)定，與IEC156差別(bie)很小(xiao)。GB/T507—1986和DL/T429—1991這兩種(zhong)標準的(de)(de)測試(shi)(shi)(shi)方(fang)(fang)法(fa)(fa)(前(qian)(qian)者簡稱“方(fang)(fang)法(fa)(fa)一”，后(hou)者簡稱“方(fang)(fang)法(fa)(fa)二”)差別(bie)較(jiao)大(da)。絕(jue)(jue)(jue)大(da)多數采(cai)用(yong)方(fang)(fang)法(fa)(fa)二測試(shi)(shi)(shi)絕(jue)(jue)(jue)緣油(you)(you)擊(ji)穿電(dian)(dian)(dian)壓(ya)，即以平板(ban)倒角形電(dian)(dian)(dian)極和較(jiao)小(xiao)的(de)(de)油(you)(you)杯(bei)進行測試(shi)(shi)(shi)，但又忽略(lve)了DL/T429—1991中(zhong)的(de)(de)注釋，無論是什么狀態的(de)(de)油(you)(you)，從什么電(dian)(dian)(dian)壓(ya)等(deng)級的(de)(de)電(dian)(dian)(dian)氣(qi)(qi)設備中(zhong)采(cai)集(ji)的(de)(de)油(you)(you)樣(yang)，統(tong)統(tong)都用(yong)方(fang)(fang)法(fa)(fa)二進行測試(shi)(shi)(shi)。
2、原因分析
在電力系統(tong)中基本上采用(yong)方法二測試絕緣(yuan)油擊穿(chuan)電壓，這種狀(zhuang)況(kuang)的形(xing)成有歷史沿革的原因，也(ye)有方法一用(yong)油量大的原因。
多(duo)年(nian)來(lai)，各用(yong)油(you)(you)(you)部門一(yi)直(zhi)采(cai)(cai)(cai)用(yong)方(fang)法二進行擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓的(de)(de)(de)(de)(de)(de)(de)(de)測(ce)試(shi)，相應的(de)(de)(de)(de)(de)(de)(de)(de)試(shi)驗(yan)(yan)(yan)(yan)設(she)備(bei)(如(ru)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)、油(you)(you)(you)杯(bei)(bei))都(dou)(dou)為適應方(fang)法二而設(she)計(ji)(ji)。要嚴(yan)格執行標(biao)準，針對(dui)不(bu)(bu)(bu)(bu)同(tong)油(you)(you)(you)樣(yang)(yang)，隨時更(geng)換油(you)(you)(you)杯(bei)(bei)、電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)，必須對(dui)測(ce)試(shi)設(she)備(bei)進行更(geng)新改造，這(zhe)給試(shi)驗(yan)(yan)(yan)(yan)人員增添了(le)許多(duo)麻(ma)煩。絕(jue)大(da)(da)多(duo)數情況下，試(shi)驗(yan)(yan)(yan)(yan)人員就(jiu)(jiu)用(yong)一(yi)種(zhong)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)、一(yi)種(zhong)油(you)(you)(you)杯(bei)(bei)測(ce)試(shi)所有油(you)(you)(you)樣(yang)(yang)，若試(shi)驗(yan)(yan)(yan)(yan)結(jie)果能滿足不(bu)(bu)(bu)(bu)同(tong)等級要求的(de)(de)(de)(de)(de)(de)(de)(de)絕(jue)緣油(you)(you)(you)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓標(biao)準，這(zhe)也(ye)是一(yi)種(zhong)不(bu)(bu)(bu)(bu)錯的(de)(de)(de)(de)(de)(de)(de)(de)選擇，而且不(bu)(bu)(bu)(bu)會產生任何分(fen)歧，但(dan)(dan)是，如(ru)果測(ce)定(ding)(ding)值介于(yu)合(he)(he)格與不(bu)(bu)(bu)(bu)合(he)(he)格之間(jian)，麻(ma)煩就(jiu)(jiu)出(chu)現了(le)。例(li)如(ru)，需(xu)測(ce)定(ding)(ding)一(yi)臺500kV運(yun)行中(zhong)(zhong)變壓器(qi)油(you)(you)(you)的(de)(de)(de)(de)(de)(de)(de)(de)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓，采(cai)(cai)(cai)用(yong)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和(he)(he)小(xiao)油(you)(you)(you)杯(bei)(bei)，以(yi)及(ji)相配套的(de)(de)(de)(de)(de)(de)(de)(de)升壓設(she)備(bei)等試(shi)驗(yan)(yan)(yan)(yan)設(she)備(bei)，電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)之間(jian)距(ju)離2.5mm，測(ce)定(ding)(ding)的(de)(de)(de)(de)(de)(de)(de)(de)結(jie)果為46k V，這(zhe)顯然(ran)不(bu)(bu)(bu)(bu)滿足GB/T7595—2000規(gui)(gui)定(ding)(ding)的(de)(de)(de)(de)(de)(de)(de)(de)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓不(bu)(bu)(bu)(bu)小(xiao)于(yu)50kV的(de)(de)(de)(de)(de)(de)(de)(de)要求。但(dan)(dan)是此(ci)時并不(bu)(bu)(bu)(bu)能判(pan)(pan)斷此(ci)油(you)(you)(you)樣(yang)(yang)不(bu)(bu)(bu)(bu)合(he)(he)格，因為按照DL/T429—1991中(zhong)(zhong)的(de)(de)(de)(de)(de)(de)(de)(de)注釋規(gui)(gui)定(ding)(ding)，電(dian)(dian)(dian)(dian)(dian)壓高(gao)于(yu)220kV的(de)(de)(de)(de)(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)氣設(she)備(bei)的(de)(de)(de)(de)(de)(de)(de)(de)油(you)(you)(you)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓試(shi)驗(yan)(yan)(yan)(yan)應按方(fang)法一(yi)進行。要判(pan)(pan)斷此(ci)油(you)(you)(you)樣(yang)(yang)是否(fou)合(he)(he)格，就(jiu)(jiu)必須再取樣(yang)(yang)，用(yong)球蓋(gai)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和(he)(he)大(da)(da)油(you)(you)(you)杯(bei)(bei)進行試(shi)驗(yan)(yan)(yan)(yan)。這(zhe)樣(yang)(yang)無疑(yi)給試(shi)驗(yan)(yan)(yan)(yan)工作帶來(lai)更(geng)大(da)(da)的(de)(de)(de)(de)(de)(de)(de)(de)麻(ma)煩。有些單(dan)位(wei)則采(cai)(cai)(cai)取加深本體油(you)(you)(you)處(chu)理的(de)(de)(de)(de)(de)(de)(de)(de)手段，仍用(yong)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)，直(zhi)至測(ce)定(ding)(ding)值合(he)(he)格為止(zhi)。這(zhe)樣(yang)(yang)做使(shi)絕(jue)緣油(you)(you)(you)的(de)(de)(de)(de)(de)(de)(de)(de)絕(jue)緣性更(geng)可(ke)靠，但(dan)(dan)卻加大(da)(da)了(le)處(chu)理成(cheng)本，是極(ji)(ji)(ji)(ji)(ji)不(bu)(bu)(bu)(bu)經(jing)濟(ji)的(de)(de)(de)(de)(de)(de)(de)(de)。用(yong)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)、球形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和(he)(he)球蓋(gai)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)測(ce)得的(de)(de)(de)(de)(de)(de)(de)(de)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓值有顯著的(de)(de)(de)(de)(de)(de)(de)(de)差異，GB/T7959—2000附(fu)錄B中(zhong)(zhong)對(dui)采(cai)(cai)(cai)用(yong)3種(zhong)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)測(ce)定(ding)(ding)的(de)(de)(de)(de)(de)(de)(de)(de)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓值進行了(le)比較(jiao)：采(cai)(cai)(cai)用(yong)球形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)比采(cai)(cai)(cai)用(yong)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)約高(gao)6kV;采(cai)(cai)(cai)用(yong)球蓋(gai)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)比采(cai)(cai)(cai)用(yong)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)高(gao)3～6 k V;當(dang)油(you)(you)(you)的(de)(de)(de)(de)(de)(de)(de)(de)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓值在(zai)30kV以(yi)下時，球形(xing)(xing)(xing)和(he)(he)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)(de)(de)(de)(de)測(ce)定(ding)(ding)值基本一(yi)致(zhi)。但(dan)(dan)這(zhe)只是一(yi)種(zhong)統(tong)計(ji)(ji)規(gui)(gui)律(lv)，不(bu)(bu)(bu)(bu)能簡單(dan)地把采(cai)(cai)(cai)用(yong)平(ping)(ping)板(ban)(ban)倒(dao)角(jiao)(jiao)(jiao)形(xing)(xing)(xing)電(dian)(dian)(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)測(ce)得的(de)(de)(de)(de)(de)(de)(de)(de)擊(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)(dian)(dian)壓值都(dou)(dou)加上3～6kV，對(dui)單(dan)個油(you)(you)(you)樣(yang)(yang)來(lai)說差別可(ke)能很大(da)(da)，也(ye)可(ke)能很小(xiao)。
方法一(yi)用(yong)油量大，需從電(dian)氣(qi)設備中多(duo)(duo)次(ci)取(qu)(qu)樣，對(dui)于互感器(qi)、電(dian)抗器(qi)和少油開(kai)關等少油電(dian)氣(qi)設備，多(duo)(duo)次(ci)取(qu)(qu)樣后，油量不足就(jiu)必(bi)須補油。因此很多(duo)(duo)單位都選擇方法二，以小油杯(bei)進行測試。
3、試驗方法的改進建議
(1)方(fang)法(fa)(fa)標(biao)(biao)準應(ying)向國際標(biao)(biao)準靠攏。目前IEC156的(de)試(shi)驗方(fang)法(fa)(fa)是(shi)得到世(shi)界上大多數國家承認的(de)，其通(tong)用性、先進性不容置疑。在標(biao)(biao)準化工(gong)作中(zhong)，優(you)先采用先進的(de)、國際通(tong)用的(de)標(biao)(biao)準制訂(ding)本國的(de)標(biao)(biao)準是(shi)一條(tiao)很重要(yao)的(de)原則，GB/T507—1986基(ji)本上是(shi)參(can)照IEC156制訂(ding)的(de)，要(yao)求(qiu)基(ji)本相同。
(2)考慮(lv)到(dao)運行中電氣設備的(de)(de)油(you)量(liang)稍少及(ji)測試油(you)杯(bei)的(de)(de)容量(liang)稍小對測試結(jie)果影響(xiang)不(bu)大(da)的(de)(de)情況，可對GB/T507—1986中油(you)杯(bei)容量(liang)的(de)(de)限制放寬，例如從300～500mL放寬至200～500mL。
(3)方(fang)法一比方(fang)法二更(geng)接近于絕緣油(you)的實際使用情(qing)況(kuang)，充油(you)電(dian)氣設備中(zhong)(zhong)發(fa)生油(you)隙(xi)擊穿(chuan)是(shi)在場強較高又相(xiang)(xiang)對集中(zhong)(zhong)的區域，與球形(xing)或球蓋形(xing)電(dian)極間隙(xi)更(geng)相(xiang)(xiang)似，而不(bu)同于平板倒角形(xing)電(dian)極間隙(xi)
