新聞動態
試驗變壓器之擊穿試驗的方法分析
試驗(yan)變壓器之擊穿試驗(yan)的方法分析
1、測試方法現狀
目前國內電(dian)力行業，尤其是供電(dian)系統(tong)和(he)安裝(zhuang)系統(tong)， 目前關于絕緣油(you)(you)擊(ji)穿(chuan)電(dian)壓(ya)(ya)測(ce)試(shi)(shi)(shi)方(fang)法(fa)(fa)的(de)(de)(de)(de)標準比較常(chang)用的(de)(de)(de)(de)有GB/T507—1986《電(dian)氣用油(you)(you)絕緣強度(du)測(ce)定法(fa)(fa)》和(he)DL/T429—1991《電(dian)力系統(tong)油(you)(you)質試(shi)(shi)(shi)驗方(fang)法(fa)(fa)》，其中GB/T507—1986主要參照IEC156《絕緣油(you)(you)電(dian)氣強度(du)測(ce)定方(fang)法(fa)(fa)》制定，與IEC156差(cha)別很小(xiao)。GB/T507—1986和(he)DL/T429—1991這兩(liang)種標準的(de)(de)(de)(de)測(ce)試(shi)(shi)(shi)方(fang)法(fa)(fa)(前者簡稱(cheng)“方(fang)法(fa)(fa)一”，后(hou)者簡稱(cheng)“方(fang)法(fa)(fa)二”)差(cha)別較大。絕大多(duo)數采用方(fang)法(fa)(fa)二測(ce)試(shi)(shi)(shi)絕緣油(you)(you)擊(ji)穿(chuan)電(dian)壓(ya)(ya)，即以平板倒(dao)角形電(dian)極和(he)較小(xiao)的(de)(de)(de)(de)油(you)(you)杯進行測(ce)試(shi)(shi)(shi)，但(dan)又忽略(lve)了(le)DL/T429—1991中的(de)(de)(de)(de)注釋，無論是什么狀態的(de)(de)(de)(de)油(you)(you)，從什么電(dian)壓(ya)(ya)等級(ji)的(de)(de)(de)(de)電(dian)氣設備中采集的(de)(de)(de)(de)油(you)(you)樣，統(tong)統(tong)都(dou)用方(fang)法(fa)(fa)二進行測(ce)試(shi)(shi)(shi)。
2、原因分析
在電力(li)系(xi)統中(zhong)基本上采用(yong)方法二測試絕緣油(you)擊穿電壓，這種(zhong)狀況的(de)(de)形(xing)成有歷史沿革的(de)(de)原(yuan)(yuan)因(yin)，也有方法一用(yong)油(you)量大(da)的(de)(de)原(yuan)(yuan)因(yin)。
多(duo)年來，各用(yong)(yong)(yong)油(you)(you)(you)(you)(you)部門一直采用(yong)(yong)(yong)方(fang)法(fa)二進(jin)(jin)行(xing)(xing)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)的(de)(de)(de)(de)(de)測(ce)(ce)試(shi)(shi)，相應的(de)(de)(de)(de)(de)試(shi)(shi)驗(yan)(yan)設(she)(she)備(如電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)、油(you)(you)(you)(you)(you)杯(bei))都為(wei)(wei)適應方(fang)法(fa)二而設(she)(she)計。要(yao)嚴格執行(xing)(xing)標(biao)準，針對(dui)不(bu)(bu)同油(you)(you)(you)(you)(you)樣(yang)，隨時(shi)(shi)更換油(you)(you)(you)(you)(you)杯(bei)、電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)，必須對(dui)測(ce)(ce)試(shi)(shi)設(she)(she)備進(jin)(jin)行(xing)(xing)更新改(gai)造，這(zhe)(zhe)給試(shi)(shi)驗(yan)(yan)人員增(zeng)添(tian)了(le)許多(duo)麻煩。絕(jue)大(da)(da)多(duo)數情(qing)況下，試(shi)(shi)驗(yan)(yan)人員就用(yong)(yong)(yong)一種電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)、一種油(you)(you)(you)(you)(you)杯(bei)測(ce)(ce)試(shi)(shi)所有油(you)(you)(you)(you)(you)樣(yang)，若試(shi)(shi)驗(yan)(yan)結(jie)果能(neng)滿足不(bu)(bu)同等(deng)(deng)級要(yao)求(qiu)(qiu)的(de)(de)(de)(de)(de)絕(jue)緣油(you)(you)(you)(you)(you)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)標(biao)準，這(zhe)(zhe)也(ye)是(shi)(shi)(shi)一種不(bu)(bu)錯(cuo)的(de)(de)(de)(de)(de)選擇(ze)，而且(qie)不(bu)(bu)會產生任何分(fen)歧，但(dan)是(shi)(shi)(shi)，如果測(ce)(ce)定(ding)(ding)(ding)(ding)(ding)值(zhi)(zhi)介于(yu)(yu)合格與不(bu)(bu)合格之間(jian)，麻煩就出(chu)現了(le)。例如，需測(ce)(ce)定(ding)(ding)(ding)(ding)(ding)一臺500kV運行(xing)(xing)中(zhong)變(bian)壓(ya)(ya)(ya)器(qi)油(you)(you)(you)(you)(you)的(de)(de)(de)(de)(de)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)，采用(yong)(yong)(yong)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和(he)小(xiao)油(you)(you)(you)(you)(you)杯(bei)，以及相配(pei)套的(de)(de)(de)(de)(de)升壓(ya)(ya)(ya)設(she)(she)備等(deng)(deng)試(shi)(shi)驗(yan)(yan)設(she)(she)備，電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)之間(jian)距離2.5mm，測(ce)(ce)定(ding)(ding)(ding)(ding)(ding)的(de)(de)(de)(de)(de)結(jie)果為(wei)(wei)46k V，這(zhe)(zhe)顯(xian)然不(bu)(bu)滿足GB/T7595—2000規定(ding)(ding)(ding)(ding)(ding)的(de)(de)(de)(de)(de)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)不(bu)(bu)小(xiao)于(yu)(yu)50kV的(de)(de)(de)(de)(de)要(yao)求(qiu)(qiu)。但(dan)是(shi)(shi)(shi)此時(shi)(shi)并(bing)不(bu)(bu)能(neng)判(pan)斷此油(you)(you)(you)(you)(you)樣(yang)不(bu)(bu)合格，因為(wei)(wei)按照DL/T429—1991中(zhong)的(de)(de)(de)(de)(de)注釋規定(ding)(ding)(ding)(ding)(ding)，電(dian)(dian)(dian)壓(ya)(ya)(ya)高于(yu)(yu)220kV的(de)(de)(de)(de)(de)電(dian)(dian)(dian)氣設(she)(she)備的(de)(de)(de)(de)(de)油(you)(you)(you)(you)(you)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)試(shi)(shi)驗(yan)(yan)應按方(fang)法(fa)一進(jin)(jin)行(xing)(xing)。要(yao)判(pan)斷此油(you)(you)(you)(you)(you)樣(yang)是(shi)(shi)(shi)否合格，就必須再取(qu)樣(yang)，用(yong)(yong)(yong)球(qiu)蓋形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和(he)大(da)(da)油(you)(you)(you)(you)(you)杯(bei)進(jin)(jin)行(xing)(xing)試(shi)(shi)驗(yan)(yan)。這(zhe)(zhe)樣(yang)無疑給試(shi)(shi)驗(yan)(yan)工作帶來更大(da)(da)的(de)(de)(de)(de)(de)麻煩。有些(xie)單(dan)位則采取(qu)加深本(ben)體油(you)(you)(you)(you)(you)處理(li)的(de)(de)(de)(de)(de)手段，仍用(yong)(yong)(yong)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)，直至測(ce)(ce)定(ding)(ding)(ding)(ding)(ding)值(zhi)(zhi)合格為(wei)(wei)止(zhi)。這(zhe)(zhe)樣(yang)做使絕(jue)緣油(you)(you)(you)(you)(you)的(de)(de)(de)(de)(de)絕(jue)緣性更可靠，但(dan)卻加大(da)(da)了(le)處理(li)成(cheng)本(ben)，是(shi)(shi)(shi)極(ji)(ji)(ji)(ji)(ji)不(bu)(bu)經(jing)濟的(de)(de)(de)(de)(de)。用(yong)(yong)(yong)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)、球(qiu)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)和(he)球(qiu)蓋形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)測(ce)(ce)得的(de)(de)(de)(de)(de)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)值(zhi)(zhi)有顯(xian)著的(de)(de)(de)(de)(de)差(cha)異(yi)，GB/T7959—2000附(fu)錄B中(zhong)對(dui)采用(yong)(yong)(yong)3種電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)測(ce)(ce)定(ding)(ding)(ding)(ding)(ding)的(de)(de)(de)(de)(de)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)值(zhi)(zhi)進(jin)(jin)行(xing)(xing)了(le)比(bi)較(jiao)：采用(yong)(yong)(yong)球(qiu)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)比(bi)采用(yong)(yong)(yong)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)約高6kV;采用(yong)(yong)(yong)球(qiu)蓋形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)比(bi)采用(yong)(yong)(yong)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)高3～6 k V;當油(you)(you)(you)(you)(you)的(de)(de)(de)(de)(de)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)值(zhi)(zhi)在30kV以下時(shi)(shi)，球(qiu)形(xing)和(he)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)的(de)(de)(de)(de)(de)測(ce)(ce)定(ding)(ding)(ding)(ding)(ding)值(zhi)(zhi)基(ji)本(ben)一致。但(dan)這(zhe)(zhe)只(zhi)是(shi)(shi)(shi)一種統計規律，不(bu)(bu)能(neng)簡單(dan)地(di)把采用(yong)(yong)(yong)平(ping)板倒(dao)(dao)(dao)角(jiao)形(xing)電(dian)(dian)(dian)極(ji)(ji)(ji)(ji)(ji)測(ce)(ce)得的(de)(de)(de)(de)(de)擊(ji)(ji)(ji)穿(chuan)(chuan)(chuan)電(dian)(dian)(dian)壓(ya)(ya)(ya)值(zhi)(zhi)都加上(shang)3～6kV，對(dui)單(dan)個油(you)(you)(you)(you)(you)樣(yang)來說(shuo)差(cha)別可能(neng)很(hen)大(da)(da)，也(ye)可能(neng)很(hen)小(xiao)。
方(fang)(fang)法一用油(you)量大，需從電氣設備中多(duo)(duo)次取樣(yang)，對(dui)于互(hu)感(gan)器、電抗器和少油(you)開關等(deng)少油(you)電氣設備，多(duo)(duo)次取樣(yang)后，油(you)量不足就必須補油(you)。因此很多(duo)(duo)單位都選擇方(fang)(fang)法二，以小油(you)杯進行測試。
3、試驗方法的改進建(jian)議
(1)方法標(biao)準(zhun)(zhun)應向國際(ji)標(biao)準(zhun)(zhun)靠攏。目(mu)前IEC156的(de)(de)(de)試驗(yan)方法是得到世界上大多數國家承認的(de)(de)(de)，其通用性、先(xian)進(jin)性不容置疑。在標(biao)準(zhun)(zhun)化工作中，優先(xian)采用先(xian)進(jin)的(de)(de)(de)、國際(ji)通用的(de)(de)(de)標(biao)準(zhun)(zhun)制訂本(ben)國的(de)(de)(de)標(biao)準(zhun)(zhun)是一條很重要的(de)(de)(de)原(yuan)則，GB/T507—1986基本(ben)上是參照IEC156制訂的(de)(de)(de)，要求基本(ben)相同。
(2)考慮到(dao)運行(xing)中電氣(qi)設備的油量(liang)稍少及測試油杯(bei)的容(rong)量(liang)稍小對(dui)測試結果影(ying)響不大的情(qing)況，可對(dui)GB/T507—1986中油杯(bei)容(rong)量(liang)的限制放寬，例如(ru)從300～500mL放寬至200～500mL。
(3)方法一比方法二(er)更接(jie)近于(yu)絕緣油的(de)實際(ji)使用情況，充油電(dian)(dian)氣設備中發生油隙擊穿是在場強較(jiao)高又相對集(ji)中的(de)區域，與(yu)球(qiu)形或球(qiu)蓋形電(dian)(dian)極間(jian)隙更相似，而(er)不同于(yu)平板倒角形電(dian)(dian)極間(jian)隙
