電容器介質損耗因數的測試目的

電(dian)容(rong)(rong)器(qi)介(jie)質損耗因數(shu)和電(dian)容(rong)(rong)器(qi)絕(jue)(jue)緣(yuan)介(jie)質的(de)種(zhong)類、厚度、浸漬劑的(de)特性以(yi)及制造(zao)(zao)工(gong)藝(yi)有(you)關(guan)。電(dian)容(rong)(rong)器(qi)tanδ的(de)測量能靈敏(min)地反映電(dian)容(rong)(rong)器(qi)絕(jue)(jue)緣(yuan)介(jie)質受潮(chao)、擊穿等絕(jue)(jue)緣(yuan)缺陷(xian)，對(dui)制造(zao)(zao)過程中真空(kong)處理和剩余壓(ya)力、引(yin)線端子焊(han)接不良(liang)、有(you)毛刺、鋁箔或膜紙(zhi)不平整等工(gong)藝(yi)的(de)問(wen)題也有(you)較靈敏(min)的(de)反應，所以(yi)說(shuo)電(dian)容(rong)(rong)器(qi)介(jie)質損耗因數(shu)是電(dian)容(rong)(rong)器(qi)絕(jue)(jue)緣(yuan)優(you)劣的(de)重要指(zhi)標。

耦合電容器測試介質損耗因數的測試

測試接線

一般(ban)采用(yong)(yong)正(zheng)(zheng)接(jie)線(xian)，分析(xi)比較(jiao)時(shi)(shi)采用(yong)(yong)反(fan)(fan)接(jie)線(xian)測(ce)(ce)量(liang)(liang)。正(zheng)(zheng)接(jie)線(xian)測(ce)(ce)試接(jie)線(xian)如(ru)圖5-4(a)所(suo)示(shi)，反(fan)(fan)接(jie)線(xian)測(ce)(ce)試接(jie)線(xian)如(ru)圖5-4(b)所(suo)示(shi)。采用(yong)(yong)正(zheng)(zheng)接(jie)線(xian)測(ce)(ce)量(liang)(liang)時(shi)(shi)，耦合(he)電(dian)(dian)容器(qi)高壓(ya)(ya)電(dian)(dian)極(ji)接(jie)測(ce)(ce)試電(dian)(dian)壓(ya)(ya)，法蘭(lan)接(jie)地，耦合(he)電(dian)(dian)容器(qi)低(di)壓(ya)(ya)電(dian)(dian)極(ji)小(xiao)(xiao)套管(guan)(guan)接(jie)電(dian)(dian)橋(qiao)Cx端(duan)，若被(bei)試品沒有(you)小(xiao)(xiao)套管(guan)(guan)， C,端(duan)與法蘭(lan)連接(jie)并墊(dian)絕緣物測(ce)(ce)量(liang)(liang)。采用(yong)(yong)反(fan)(fan)接(jie)線(xian)時(shi)(shi)，耦合(he)電(dian)(dian)容器(qi)高壓(ya)(ya)電(dian)(dian)極(ji)接(jie)電(dian)(dian)橋(qiao)C,端(duan)法蘭(lan)和小(xiao)(xiao)套管(guan)(guan)接(jie)地。

測試步驟

采用正接(jie)線測(ce)量時(shi)，先將被(bei)試(shi)(shi)電(dian)(dian)容(rong)器對地(di)放電(dian)(dian)并(bing)接(jie)地(di)，拆(chai)除被(bei)試(shi)(shi)電(dian)(dian)容(rong)器對外所有一次(ci)連接(jie)線，電(dian)(dian)容(rong)器法蘭接(jie)地(di)，打開小套(tao)管接(jie)地(di)線并(bing)與電(dian)(dian)橋C,端相連接(jie)，高壓(ya)引(yin)線接(jie)至(zhi)電(dian)(dian)容(rong)器高壓(ya)電(dian)(dian)極，取下接(jie)地(di)線，檢查接(jie)線無誤后，通(tong)知其他人員遠(yuan)離被(bei)試(shi)(shi)品并(bing)監護。合上試(shi)(shi)驗電(dian)(dian)源，從零開始升(sheng)壓(ya)至(zhi)測(ce)試(shi)(shi)電(dian)(dian)壓(ya)進行測(ce)試(shi)(shi)，測(ce)試(shi)(shi)電(dian)(dian)壓(ya)為(wei)10kV。測(ce)試(shi)(shi)完畢后先將電(dian)(dian)壓(ya)降到(dao)零，然后讀取測(ce)量數據(ju)，切斷(duan)電(dian)(dian)源，對被(bei)試(shi)(shi)品進行放電(dian)(dian)并(bing)接(jie)地(di)，拆(chai)除測(ce)試(shi)(shi)引(yin)線。特別注意小套(tao)管接(jie)地(di)引(yin)線的恢復。

采(cai)用反接(jie)(jie)(jie)(jie)(jie)線(xian)測量(liang)時，電(dian)橋Cx端接(jie)(jie)(jie)(jie)(jie)電(dian)容器高(gao)壓(ya)電(dian)極，低(di)壓(ya)電(dian)極接(jie)(jie)(jie)(jie)(jie)地。測量(liang)下節耦合(he)電(dian)容器時下法蘭(lan)和(he)小套管接(jie)(jie)(jie)(jie)(jie)地，采(cai)用反接(jie)(jie)(jie)(jie)(jie)線(xian)測量(liang)時，橋體接(jie)(jie)(jie)(jie)(jie)地應直接(jie)(jie)(jie)(jie)(jie)與被試品接(jie)(jie)(jie)(jie)(jie)地點直接(jie)(jie)(jie)(jie)(jie)連接(jie)(jie)(jie)(jie)(jie)，測試電(dian)壓(ya)為(wei)10kV。

斷路器電容器介質損耗因數的測試

測試接線

通常采用正(zheng)接線(xian)，如圖5-5 所示，測(ce)量時被試電容(rong)器一(yi)端接測(ce)試電壓，另一(yi)端接電橋(qiao)Cx端。如斷口電容(rong)器在安裝前測(ce)試，應注意測(ce)量端要墊絕緣物。

測試步驟

1、交接時斷(duan)口電(dian)(dian)(dian)(dian)容器(qi)(qi)的tanδ 應在安裝前測(ce)試(shi)，主要(yao)是避免(mian)斷(duan)路(lu)器(qi)(qi)滅(mie)弧室的影響。測(ce)試(shi)前先將被(bei)試(shi)電(dian)(dian)(dian)(dian)容器(qi)(qi)對(dui)(dui)地放(fang)電(dian)(dian)(dian)(dian)并(bing)接地，高壓(ya)引(yin)線接至斷(duan)路(lu)器(qi)(qi)電(dian)(dian)(dian)(dian)容器(qi)(qi)一端(duan)(duan)電(dian)(dian)(dian)(dian)極(ji)，電(dian)(dian)(dian)(dian)容器(qi)(qi)另一端(duan)(duan)接電(dian)(dian)(dian)(dian)橋Cx端(duan)(duan)。取下接地線，檢(jian)查接線無誤后(hou)，通知其他人員(yuan)遠離(li)被(bei)試(shi)電(dian)(dian)(dian)(dian)容器(qi)(qi)。合上試(shi)驗電(dian)(dian)(dian)(dian)源，從零開始升壓(ya)至測(ce)試(shi)電(dian)(dian)(dian)(dian)壓(ya)進行測(ce)試(shi)，測(ce)試(shi)電(dian)(dian)(dian)(dian)壓(ya)為(wei)10kV。測(ce)試(shi)完畢后(hou)將電(dian)(dian)(dian)(dian)壓(ya)降(jiang)到零后(hou)讀取測(ce)量數(shu)據，然后(hou)切(qie)斷(duan)電(dian)(dian)(dian)(dian)源，對(dui)(dui)被(bei)試(shi)品(pin)進行放(fang)電(dian)(dian)(dian)(dian)并(bing)接地

2、預防性試驗(yan)時，如果測試數據偏大，可(ke)將電容器拆下(xia)進行(xing)測試。

電容器介質損耗因(yin)數測(ce)試注(zhu)意事項

測試電容器介質損耗因數的注意事項有:

1、測(ce)試應(ying)在良(liang)好的天氣(qi)下進行(xing)，電(dian)容器本身及環(huan)境溫度不低(di)于+5℃，電(dian)容器表面臟污(wu)、潮濕時(shi)，應(ying)采取擦拭和烘干等(deng)措施減少表面泄漏(lou)電(dian)流的影響，必要時(shi)加屏(ping)蔽(bi)環(huan)屏(ping)蔽(bi)表面泄漏(lou)電(dian)流。

2、采(cai)用反接(jie)線測量時，電橋(qiao)本(ben)體用截面較大的裸銅導線可(ke)靠接(jie)地(di)(di)，接(jie)地(di)(di)點(dian)應直接(jie)與被試品(pin)接(jie)地(di)(di)點(dian)直接(jie)連接(jie)

3、接線緊湊、布置(zhi)合理，注(zhu)意電場、磁(ci)場干擾(rao)。測試(shi)現場如(ru)有(you)電場或磁(ci)場干擾(rao)應(ying)采用移(yi)相(xiang)法、倒相(xiang)法或變頻法等抗干擾(rao)法進行測量。

4、高壓引線連接(jie)應(ying)緊密(mi)牢(lao)靠，否則(ze)接(jie)觸電阻會對(dui)膜紙復合(he)絕緣電容器 tanδ帶來誤差。

5、測試前(qian)必須檢查(cha)電(dian)容(rong)器是否漏(lou)油(you)。如漏(lou)油(you)，則電(dian)容(rong)器應退出運行(xing)，不必進(jin)行(xing)測試。

6、電容器(qi) tanδ測量通常采用(yong)正(zheng)接線。如果檢查瓷套絕緣狀(zhuang)況，可使用(yong)反接線測試，反接線能反映瓷套裂(lie)紋及內壁受潮的絕緣缺陷。

例如

一臺型號為 OY-110/√3-0.01的(de)(de)耦(ou)合電(dian)容(rong)(rong)(rong)器,原始tanδ測(ce)試(shi)數(shu)據是(shi)0.2%，電(dian)容(rong)(rong)(rong)量(liang)0.00998μF，測(ce)試(shi)環(huan)境溫度 29℃，本次(ci)測(ce)試(shi)數(shu)據 0.3%，電(dian)容(rong)(rong)(rong)量(liang)0.011μF，測(ce)試(shi)環(huan)境溫度30℃，tanδ增大，電(dian)容(rong)(rong)(rong)量(liang)增長(chang)明顯，仔細檢查(cha)發現(xian)耦(ou)合電(dian)容(rong)(rong)(rong)器上法蘭與瓷套(tao)結合處滲油(you)。分析(xi)認為耦(ou)合電(dian)容(rong)(rong)(rong)器密封不嚴進(jin)水受(shou)潮(chao)(chao)，導致絕(jue)緣劣化。因為良好的(de)(de)油(you)紙(zhi)絕(jue)緣的(de)(de)tan在10~30℃范圍內是(shi)穩(wen)定的(de)(de)或(huo)變化很小(xiao)的(de)(de)，只有絕(jue)緣劣化， tanδ變化才會明顯，電(dian)容(rong)(rong)(rong)量(liang)增大顯著，說明電(dian)容(rong)(rong)(rong)器進(jin)水受(shou)潮(chao)(chao)，因為水的(de)(de)介電(dian)系數(shu)比電(dian)容(rong)(rong)(rong)器油(you)要高。

7、電容(rong)(rong)器內部元(yuan)件為串(chuan)聯(lian)、并聯(lian)結構，特(te)別是耦合電容(rong)(rong)器等電容(rong)(rong)器串(chuan)聯(lian)元(yuan)件較多，，別元(yuan)件短(duan)路(lu)、開路(lu)或劣化，tanδ反應并不是很靈敏，還要結合電容(rong)(rong)量的變化綜合判斷。