變壓器(qi)繞組測(ce)溫系統的必要性

變壓器可分為油浸式變壓器和干式變壓器，除一些特殊用途的中小容量變壓器和氣體變壓器外，絕大多數大中型變壓器仍使用變壓器油作為冷卻和絕緣介質的油浸變壓器。油浸式變壓器絕緣采用油紙絕緣結構形式，壽命主要取決于固體絕緣(纖維紙)壽命，促使絕緣老化的主要因素是溫度、水分和氧氣等，其中變壓器繞組運行時產生繞組溫度升高產生的熱效應作用最為突出，是變壓器老化的決定性因素。
根據(ju)相(xiang)關資料統計，在變(bian)(bian)壓(ya)(ya)器事(shi)故中(zhong)，因繞(rao)組超溫運(yun)行，導致絕緣老化，變(bian)(bian)壓(ya)(ya)器繞(rao)組擊穿、燒損事(shi)故占有相(xiang)當大比例。因此準確、實(shi)時的監測變(bian)(bian)壓(ya)(ya)器繞(rao)組及其絕緣油(you)的溫度(du)是保證(zheng)變(bian)(bian)壓(ya)(ya)器正常運(yun)行的必要條(tiao)件。

變壓器油溫計的原理

現有監(jian)測(ce)繞(rao)(rao)(rao)組熱點溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)的(de)(de)溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)表(biao)稱(cheng)為(wei)繞(rao)(rao)(rao)溫(wen)(wen)(wen)(wen)(wen)表(biao)，監(jian)測(ce)絕緣(yuan)油(you)(you)溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)的(de)(de)溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)表(biao)稱(cheng)為(wei)油(you)(you)溫(wen)(wen)(wen)(wen)(wen)表(biao)，一(yi)個(ge)油(you)(you)浸(jin)式變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)一(yi)般需要兩個(ge)油(you)(you)溫(wen)(wen)(wen)(wen)(wen)表(biao)監(jian)測(ce)頂(ding)層和底(di)層油(you)(you)面溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)，一(yi)個(ge)繞(rao)(rao)(rao)溫(wen)(wen)(wen)(wen)(wen)表(biao)監(jian)測(ce)繞(rao)(rao)(rao)組熱點溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)。其(qi)中(zhong)，油(you)(you)溫(wen)(wen)(wen)(wen)(wen)表(biao)由溫(wen)(wen)(wen)(wen)(wen)包(bao)(bao)、毛細管、彈(dan)(dan)性(xing)元(yuan)(yuan)件、壓(ya)敏電(dian)(dian)阻等元(yuan)(yuan)件封閉構成，將溫(wen)(wen)(wen)(wen)(wen)包(bao)(bao)通(tong)過(guo)襯(chen)管插(cha)入，使(shi)溫(wen)(wen)(wen)(wen)(wen)包(bao)(bao)浸(jin)沒在(zai)變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)油(you)(you)中(zhong)，并旋轉固定，當變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)油(you)(you)溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)升高時，溫(wen)(wen)(wen)(wen)(wen)包(bao)(bao)內(nei)的(de)(de)液體(ti)膨(peng)脹，通(tong)過(guo)毛細管將壓(ya)力傳送到(dao)彈(dan)(dan)性(xing)元(yuan)(yuan)件(布爾登管)。彈(dan)(dan)性(xing)元(yuan)(yuan)件連接到(dao)指針心(xin)(xin)軸(zhou)，驅動心(xin)(xin)軸(zhou)轉動，從而(er)(er)將溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)變(bian)(bian)(bian)化和當前溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)值指示到(dao)刻度(du)(du)(du)盤(pan)上(shang)，這是一(yi)個(ge)純機械的(de)(de)測(ce)量系(xi)統，不需要外部(bu)輸入功率。而(er)(er)繞(rao)(rao)(rao)溫(wen)(wen)(wen)(wen)(wen)表(biao)只是在(zai)油(you)(you)溫(wen)(wen)(wen)(wen)(wen)表(biao)基礎上(shang)增加了一(yi)個(ge)電(dian)(dian)流匹配器(qi)(qi)(qi)和一(yi)個(ge)電(dian)(dian)熱元(yuan)(yuan)件，溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)計的(de)(de)傳感器(qi)(qi)(qi)(溫(wen)(wen)(wen)(wen)(wen)包(bao)(bao))插(cha)在(zai)變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)油(you)(you)箱頂(ding)部(bu)的(de)(de)溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)計座內(nei)，當變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)負載為(wei)零時，繞(rao)(rao)(rao)組溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)計的(de)(de)讀數為(wei)變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)油(you)(you)箱頂(ding)層油(you)(you)面的(de)(de)溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)，當變(bian)(bian)(bian)壓(ya)器(qi)(qi)(qi)帶上(shang)負載后，通(tong)過(guo)電(dian)(dian)流互感器(qi)(qi)(qi)取(qu)出的(de)(de)與負荷成正比的(de)(de)電(dian)(dian)流，經電(dian)(dian)流匹配器(qi)(qi)(qi)調整后流經彈(dan)(dan)性(xing)元(yuan)(yuan)件內(nei)的(de)(de)電(dian)(dian)熱元(yuan)(yuan)件，使(shi)彈(dan)(dan)性(xing)元(yuan)(yuan)件的(de)(de)位移量增加，從而(er)(er)指示繞(rao)(rao)(rao)組溫(wen)(wen)(wen)(wen)(wen)度(du)(du)(du)。

變壓器油溫計的缺點
現有(you)變壓器監測(ce)不足(zu)之處在于：1、無法準確反(fan)饋(kui)熱點溫(wen)度，2、功能簡(jian)單，3、可擴展性差。

無法準確反(fan)饋熱(re)點溫(wen)(wen)度的原(yuan)因是：傳(chuan)統(tong)繞溫(wen)(wen)表使用的是熱(re)模擬(ni)測量法，在(zai)穩態的情況下是可以直(zhi)接(jie)參考的，但在(zai)動態下受到油(you)對熱(re)源熱(re)交換時間常數較(jiao)(jiao)大的影響，有一定的局(ju)限性(xing)，在(zai)超額定電流(liu)運(yun)(yun)行(xing)時也(ye)不能準確地反(fan)映繞組溫(wen)(wen)度。另外若運(yun)(yun)行(xing)中的變(bian)壓(ya)器采用強油(you)循環(huan)或(huo)冷(leng)氣器，在(zai)不同(tong)的負載(zai)條件(jian)或(huo)溫(wen)(wen)度下，所投入的冷(leng)卻器數量不同(tong)，從而(er)變(bian)壓(ya)器內部(bu)油(you)流(liu)速(su)有較(jiao)(jiao)大的變(bian)化,進而(er)引起變(bian)壓(ya)器繞組對油(you)的溫(wen)(wen)升(sheng)特性(xing)發生較(jiao)(jiao)大的變(bian)化，這樣就可能在(zai)某些(xie)工況下，變(bian)壓(ya)器的溫(wen)(wen)升(sheng)特性(xing)與溫(wen)(wen)度計電熱(re)元(yuan)件(jian)的溫(wen)(wen)升(sheng)特性(xing)有較(jiao)(jiao)大的差(cha)別。

油變光纖測溫系統

變壓器光纖測溫(wen)系(xi)統是多(duo)(duo)(duo)測溫(wen)通(tong)(tong)道，包(bao)括多(duo)(duo)(duo)路油面溫(wen)度和(he)多(duo)(duo)(duo)路繞(rao)(rao)組(zu)熱(re)點溫(wen)度、多(duo)(duo)(duo)個可(ke)(ke)單獨設置(zhi)報警策略的微動開關、多(duo)(duo)(duo)路4-20mA模擬輸出、串口RS485、LAN通(tong)(tong)信(xin)接口等功能。相(xiang)較于傳統的指(zhi)針式油溫(wen)和(he)繞(rao)(rao)組(zu)熱(re)點溫(wen)度測量裝置(zhi)，具有兼容原有油溫(wen)繞(rao)(rao)溫(wen)測量報警系(xi)統、溫(wen)度及(ji)報警信(xin)息直觀、測溫(wen)準(zhun)確(que)，穩定性(xing)(xing)好，可(ke)(ke)靠性(xing)(xing)強，可(ke)(ke)擴展性(xing)(xing)強的優(you)勢(shi)，滿足未來智能化變電站要求。

一個(ge)裝置替換傳(chuan)(chuan)統(tong)多塊(kuai)繞溫(wen)表(biao)(biao)、油(you)溫(wen)表(biao)(biao)的；對傳(chuan)(chuan)統(tong)油(you)浸(jin)式變壓(ya)器測溫(wen)系統(tong)的完美兼(jian)容，無需較大改(gai)動即可實(shi)現替換；模塊(kuai)化(hua)設計，通過總線控(kong)制(zhi)，實(shi)現更多功能(neng)；數(shu)字(zi)化(hua)溫(wen)度(du)處理，針對不同場(chang)景有不同的測溫(wen)算法(fa)，測溫(wen)更精準；數(shu)字(zi)化(hua)通信控(kong)制(zhi)，滿(man)足未來(lai)無人巡(xun)檢，自(zi)動控(kong)制(zhi)，智能(neng)化(hua)管(guan)控(kong)需求。