三相干式變壓器的工作原理是基于電(dian)(dian)磁感(gan)應定律來改變電(dian)(dian)壓。
1.三(san)相干式(shi)變(bian)(bian)壓(ya)(ya)(ya)器(qi)是利用(yong)電(dian)(dian)磁感應(ying)的原(yuan)理(li)來改變(bian)(bian)交流電(dian)(dian)壓(ya)(ya)(ya)的裝置,主(zhu)要構件包括初(chu)級線(xian)圈(quan)、次級線(xian)圈(quan)和鐵心(xin)(磁芯(xin))。其工作原(yuan)理(li)是將一(yi)組(zu)繞組(zu)繞在磁鐵芯(xin)上,通過改變(bian)(bian)輸(shu)(shu)入繞組(zu)與輸(shu)(shu)出繞組(zu)的匝(za)(za)數(shu)比例,實現(xian)電(dian)(dian)壓(ya)(ya)(ya)的升降。當(dang)輸(shu)(shu)入繞組(zu)的匝(za)(za)數(shu)比輸(shu)(shu)出繞組(zu)的匝(za)(za)數(shu)少時,輸(shu)(shu)出電(dian)(dian)壓(ya)(ya)(ya)會升高(gao);反之亦然。因此,干式(shi)變(bian)(bian)壓(ya)(ya)(ya)器(qi)可(ke)以實現(xian)從380V到1140V的電(dian)(dian)壓(ya)(ya)(ya)轉換。
2.三(san)相干式變壓(ya)器使用(yong)(yong)空(kong)氣作為冷卻介質,沒有油來實(shi)現(xian)絕緣(yuan),這種變壓(ya)器的主要結構包括(kuo)磁(ci)路部(bu)(bu)分(fen)(fen)和繞(rao)(rao)組(zu)部(bu)(bu)分(fen)(fen)。磁(ci)路部(bu)(bu)分(fen)(fen)由硅鋼片(pian)等磁(ci)性材料組(zu)成,用(yong)(yong)于導磁(ci)并產生磁(ci)通;繞(rao)(rao)組(zu)部(bu)(bu)分(fen)(fen)由線圈(quan)組(zu)成,通過互感作用(yong)(yong)實(shi)現(xian)電壓(ya)的變換。在繞(rao)(rao)組(zu)上,通常采用(yong)(yong)多層絕緣(yuan)紙或(huo)絕緣(yuan)片(pian)進行絕緣(yuan)和隔離(li)。
3.三(san)(san)相(xiang)干式(shi)變(bian)壓(ya)器(qi)的連(lian)接(jie)(jie)方(fang)式(shi)有(you)多(duo)種,包括星(xing)形(xing)、三(san)(san)角(jiao)(jiao)形(xing)和(he)鋸齒形(xing)連(lian)接(jie)(jie),這些連(lian)接(jie)(jie)類型的共同點(dian)(dian)是變(bian)壓(ya)器(qi)的相(xiang)位(wei)端子在(zai)高(gao)壓(ya)側標記(ji)為1U、1V和(he)1W,在(zai)低(di)壓(ya)側標記(ji)為2U、2V和(he)2W。任何代(dai)表繞組中性點(dian)(dian)的連(lian)接(jie)(jie)點(dian)(dian)標記(ji)為1N或2N。星(xing)形(xing)連(lian)接(jie)(jie)主要(yao)用(yong)于低(di)電壓(ya)和(he)高(gao)電壓(ya)以及低(di)電流,三(san)(san)角(jiao)(jiao)形(xing)連(lian)接(jie)(jie)主要(yao)用(yong)于高(gao)額定電流和(he)低(di)電壓(ya),而(er)鋸齒形(xing)連(lian)接(jie)(jie)主要(yao)用(yong)于相(xiang)間及中性點(dian)(dian)可能出現負荷(he)不平衡的場合。