干式電力變壓器是一種常(chang)用的電力設(she)備(bei),它具(ju)有高效、可靠(kao)、安全等特點(dian)。為了確保變(bian)壓(ya)器(qi)的正(zheng)常(chang)運行,需要進行過壓(ya)和過溫保護。
過壓保護是指在變壓器輸入或輸出的電壓超過額定值時,及時采取措施將其限制在安全范圍內。一般來說,干式變壓器的(de)過壓保護可分(fen)為內部保護和外部保護兩種。
內部保護通(tong)常通(tong)過(guo)(guo)在變壓(ya)器(qi)(qi)的輸(shu)入(ru)和輸(shu)出(chu)側(ce)分別設置過(guo)(guo)壓(ya)保護器(qi)(qi)實現。這些保護器(qi)(qi)一般由過(guo)(guo)壓(ya)繼電(dian)(dian)器(qi)(qi)和電(dian)(dian)磁觸點組成(cheng),當電(dian)(dian)壓(ya)超過(guo)(guo)設定值(zhi)時,過(guo)(guo)壓(ya)繼電(dian)(dian)器(qi)(qi)會自(zi)動(dong)動(dong)作,觸點關閉(bi),從而切斷(duan)電(dian)(dian)源,實現過(guo)(guo)壓(ya)保護。同(tong)時,在變壓(ya)器(qi)(qi)輸(shu)入(ru)側(ce)還可以設置過(guo)(guo)壓(ya)繼電(dian)(dian)器(qi)(qi),用于監測輸(shu)入(ru)電(dian)(dian)源的電(dian)(dian)壓(ya),如(ru)電(dian)(dian)壓(ya)增(zeng)至(zhi)設定值(zhi)的1.1倍時,過(guo)(guo)壓(ya)繼電(dian)(dian)器(qi)(qi)就會自(zi)動(dong)動(dong)作,觸點關閉(bi),實現過(guo)(guo)壓(ya)保護。
外部保(bao)護(hu)主要通過額外的電(dian)(dian)力設(she)備和保(bao)護(hu)裝(zhuang)置實(shi)現(xian)。例如,可以為變壓(ya)(ya)(ya)(ya)器(qi)的輸入電(dian)(dian)路(lu)安裝(zhuang)過壓(ya)(ya)(ya)(ya)繼電(dian)(dian)器(qi)和斷(duan)(duan)路(lu)器(qi),在電(dian)(dian)壓(ya)(ya)(ya)(ya)超過設(she)定(ding)值時,過壓(ya)(ya)(ya)(ya)繼電(dian)(dian)器(qi)會(hui)(hui)自動動作,從而(er)切(qie)斷(duan)(duan)電(dian)(dian)源,保(bao)護(hu)變壓(ya)(ya)(ya)(ya)器(qi)。此外,在變壓(ya)(ya)(ya)(ya)器(qi)的輸出(chu)側還可以安裝(zhuang)過壓(ya)(ya)(ya)(ya)保(bao)護(hu)開(kai)(kai)關,在電(dian)(dian)壓(ya)(ya)(ya)(ya)超過設(she)定(ding)值時,過壓(ya)(ya)(ya)(ya)保(bao)護(hu)開(kai)(kai)關會(hui)(hui)自動斷(duan)(duan)開(kai)(kai)輸出(chu)電(dian)(dian)路(lu),以確保(bao)變壓(ya)(ya)(ya)(ya)器(qi)的安全(quan)運行。
過溫(wen)保(bao)護是指在變壓器的(de)溫(wen)度超過額定值時,及(ji)時采取措(cuo)施將其冷卻降溫(wen),以確保(bao)變壓器不被過熱損壞。干(gan)式(shi)變壓器的(de)過溫(wen)保(bao)護主要通過熱敏(min)繼電器和(he)溫(wen)控開關等裝置(zhi)實現。
熱(re)敏(min)(min)(min)繼(ji)電(dian)(dian)器(qi)是(shi)一種基于熱(re)敏(min)(min)(min)元件的保護(hu)裝置,當變(bian)壓(ya)器(qi)溫度超過(guo)設定值時(shi),熱(re)敏(min)(min)(min)繼(ji)電(dian)(dian)器(qi)會自動(dong)動(dong)作,觸點(dian)關(guan)閉,從而切斷電(dian)(dian)源,保護(hu)變(bian)壓(ya)器(qi)免受(shou)過(guo)熱(re)損壞。同時(shi),熱(re)敏(min)(min)(min)繼(ji)電(dian)(dian)器(qi)還可(ke)以(yi)將預(yu)警信號發送給控制系統,以(yi)提醒(xing)操(cao)作人(ren)員發生(sheng)了過(guo)溫現象。
溫(wen)控(kong)開(kai)關(guan)一般安裝在(zai)變壓(ya)器的關(guan)鍵(jian)部位(wei),如(ru)油箱、冷卻(que)器等(deng)位(wei)置。當溫(wen)度超過設定(ding)值時,溫(wen)控(kong)開(kai)關(guan)會(hui)(hui)自動斷開(kai)電路或啟動冷卻(que)系(xi)統,以降低溫(wen)度,保護變壓(ya)器。此外,溫(wen)控(kong)開(kai)關(guan)還(huan)可以監測變壓(ya)器的溫(wen)度,當溫(wen)度升高過快時,溫(wen)控(kong)開(kai)關(guan)會(hui)(hui)自動報警(jing)。
除了以上的(de)過(guo)(guo)壓(ya)和(he)過(guo)(guo)溫保護措(cuo)施,還(huan)可以通過(guo)(guo)定(ding)期(qi)檢(jian)查和(he)維護來保障變壓(ya)器的(de)安全運行。例如,定(ding)期(qi)清洗變壓(ya)器的(de)冷卻(que)(que)設備,保持冷卻(que)(que)效果良(liang)好;定(ding)期(qi)檢(jian)查電氣(qi)連(lian)接是否松動(dong)或(huo)有燒焦現象,及(ji)時進行維修或(huo)更(geng)換(huan)等。
總之,干式電力變壓器的過壓和過溫(wen)保護(hu)(hu)措施是確(que)保變(bian)壓器(qi)(qi)安全運行的重(zhong)要手(shou)段。通過合理設置過壓保護(hu)(hu)器(qi)(qi)和熱敏繼電器(qi)(qi),并(bing)配備溫(wen)控開關等裝置,可以(yi)及時發現和處(chu)理過壓和過溫(wen)現象,防(fang)止變(bian)壓器(qi)(qi)損壞,確(que)保電網(wang)的穩定運行。同時,定期檢查和維護(hu)(hu)也(ye)是保障(zhang)變(bian)壓器(qi)(qi)安全運行的重(zhong)要環節,必須得(de)到重(zhong)視。