干式變壓器在核電行業經過幾十年的發展, 目前干式變壓器已廣泛應用到各行各業的輸配電系統中, 其防火性能好, 免維護, 無污染, 抗短路能力強, 耐熱能力強, 安裝方便, 可靠性高等優點已為大家所熟知;而作為干式變壓器重要附件之一的溫度控制器, 其故障率一直相對較高, 運行可靠性較低, 長期以來困擾著眾多變壓器生產廠家及使用單位。核電行業是一個對設備可靠性要求很高的行業 , 福州英諾科技溫控器廠家結合核電行業對干式變壓器溫控器的使用要求, 提出了核電干式變壓器專用溫度控制器 的可靠性和(he)功能設計方案, 同時簡要地介紹(shao)了核電溫度控制器的電路系統設計。

核電溫控器可靠性設計方案

目(mu)前變壓器(qi)溫度(du)控制器(qi)的常見故障(zhang)主要有以下幾點(dian):

(1) 使(shi)用(yong)一(yi)段時間(jian)后(hou), 溫(wen)度測量(liang)不(bu)準確(que);

(2) Pt100鉑電阻傳感器容易(yi)損壞(huai), 可靠性不(bu)高;

(3) 誤報警(jing)、誤跳(tiao)閘引(yin)發用(yong)電安全, 給(gei)用(yong)戶(hu)造成損失。

在(zai)對上述幾點溫控器主要故障發生機理(li)進行全(quan)面(mian)分析的(de)基礎上, 核電溫控器的(de)設計(ji)引入了全(quan)新的(de)理(li)念(nian), 通過以下三(san)種設計(ji)方法全(quan)面(mian)提(ti)高其(qi)可靠(kao)性。

1.1溫度采集電(dian)路的設計

變壓(ya)器(qi)三相(xiang)低壓(ya)繞組(zu)每相(xiang)預(yu)埋一(yi)(yi)只Pt100鉑(bo)電阻(zu)(zu), 通過傳感總成線(xian)的(de)D型插(cha)頭與(yu)溫控器(qi)插(cha)座(zuo)相(xiang)連。在變壓(ya)器(qi)投運(yun)前或(huo)停運(yun)后, 如(ru)長(chang)時間處于潮濕的(de)環境中時 (核電站一(yi)(yi)般都建在沿海, 空(kong)氣(qi)長(chang)年比較潮濕) , 即使IP54防護等級的(de)溫控器(qi), 濕氣(qi)同(tong)樣會(hui)侵入。潮濕的(de)空(kong)氣(qi)會(hui)在溫控器(qi)插(cha)座(zuo)及傳感總成插(cha)頭的(de)金屬接插(cha)件表面產生氧(yang)化層, 當氧(yang)化層積累(lei)到一(yi)(yi)定厚(hou)度, 就會(hui)造成插(cha)頭座(zuo)接觸電阻(zu)(zu)增(zeng)大, 引發溫控器(qi)測(ce)溫不準(zhun)確。

核電溫(wen)(wen)(wen)控器可采(cai)用由恒流源(yuan)、多(duo)路(lu)模(mo)擬開關、運放(fang)及A/D轉換(huan)電路(lu)構成(cheng)的(de)(de)新型溫(wen)(wen)(wen)度(du)采(cai)集電路(lu)[2,3]。該電路(lu)采(cai)用四線(xian)制(zhi)Pt100鉑電阻(zu)傳感(gan)器進行溫(wen)(wen)(wen)度(du)測(ce)量, 可有效防(fang)止(zhi)傳感(gan)線(xian)導(dao)線(xian)電阻(zu)和插(cha)頭接(jie)觸電阻(zu)引入(ru)的(de)(de)測(ce)量誤差(cha), 實現長距離高(gao)精度(du)溫(wen)(wen)(wen)度(du)測(ce)量, 溫(wen)(wen)(wen)度(du)測(ce)量準確遠高(gao)于目(mu)前市場上(shang)通用的(de)(de)變(bian)壓器溫(wen)(wen)(wen)控器 (一般采(cai)用三線(xian)制(zhi)Pt100鉑電阻(zu)測(ce)溫(wen)(wen)(wen)) 。

一般來說只要接觸(chu)電(dian)阻超(chao)過1歐姆(mu), 就會引起三線制Pt100測溫電(dian)路的溫度測量(liang)超(chao)差。而(er)對于核電(dian)溫控器的溫度采(cai)集電(dian)路, 即(ji)使接觸(chu)電(dian)阻達到上百(bai)歐姆(mu), 都不會影響到其溫度測量(liang)的精(jing)度, 確保對變壓(ya)器各(ge)相繞組溫度長期準(zhun)確的測量(liang)。

1.2選(xuan)用高可靠、高防護Pt100鉑(bo)電(dian)(dian)阻傳感(gan)器, 采(cai)用Pt100斷續供電(dian)(dian)延壽設計和多余度溫度采(cai)集方法

Pt100鉑(bo)電(dian)(dian)(dian)阻(zu)(zu)傳感器(qi)是溫度控(kong)制器(qi)核心部件(jian), 其性(xing)(xing)能穩定(ding)性(xing)(xing)直(zhi)接(jie)決(jue)定(ding)溫控(kong)器(qi)的(de)可(ke)靠性(xing)(xing)。目(mu)前普通溫控(kong)器(qi)所使(shi)用(yong)的(de)Pt100鉑(bo)電(dian)(dian)(dian)阻(zu)(zu)傳感器(qi)一般是用(yong)不銹鋼(gang)保護套封(feng)裝, 對外引出三條引線, 外部防(fang)護性(xing)(xing)比較差, 在變壓(ya)器(qi)安(an)裝、運輸及調試過程(cheng)中較易(yi)損壞;同時, 由于Pt100鉑(bo)電(dian)(dian)(dian)阻(zu)(zu)傳感器(qi)長期工作在變壓(ya)器(qi)繞組附近, 在電(dian)(dian)(dian)應力、高(gao)(gao)電(dian)(dian)(dian)場、高(gao)(gao)磁場的(de)作用(yong)下, 其壽命(ming)會(hui)大大縮(suo)短(duan)。因此, 對于高(gao)(gao)可(ke)靠性(xing)(xing)要求的(de)核電(dian)(dian)(dian)溫控(kong)器(qi)必須(xu)采(cai)用(yong)高(gao)(gao)可(ke)靠、高(gao)(gao)防(fang)護的(de)Pt100鉑(bo)電(dian)(dian)(dian)阻(zu)(zu)傳感器(qi)。

目前公認(ren)的(de)(de)(de)(de)高(gao)(gao)可靠性(xing)(xing)的(de)(de)(de)(de)Pt100鉑電阻是(shi)從(cong)德國(guo)進口的(de)(de)(de)(de)薄(bo)膜(mo)鉑電阻芯片(pian), 其具有(you)體(ti)積(ji)小、抗振(zhen)性(xing)(xing)強(qiang), 元件一致性(xing)(xing)好, 熱響應時間短, 性(xing)(xing)能(neng)穩定(ding), 復現性(xing)(xing)好等特點。將Pt100鉑電阻芯片(pian)密封在(zai)不(bu)銹鋼(gang)(gang)(gang)(gang)的(de)(de)(de)(de)保(bao)護套(tao)(tao)中(zhong), 引出線外(wai)包(bao)裹高(gao)(gao)強(qiang)度不(bu)銹鋼(gang)(gang)(gang)(gang)屏(ping)蔽網(wang), 大幅提高(gao)(gao)其防護性(xing)(xing), 可有(you)效防止在(zai)變壓器(qi)的(de)(de)(de)(de)運輸、安裝及(ji)調試(shi)過程損壞鉑電阻;同(tong)時, 不(bu)銹鋼(gang)(gang)(gang)(gang)的(de)(de)(de)(de)保(bao)護套(tao)(tao)及(ji)不(bu)銹鋼(gang)(gang)(gang)(gang)屏(ping)蔽網(wang)可有(you)效屏(ping)蔽低壓繞組處的(de)(de)(de)(de)高(gao)(gao)電場(chang)、高(gao)(gao)磁場(chang), 延(yan)長Pt100鉑電阻傳感器(qi)的(de)(de)(de)(de)使用壽命(ming)。

為進一步(bu)提高(gao)鉑(bo)電(dian)(dian)阻(zu)(zu)(zu)的使用(yong)壽命, 還可(ke)采(cai)用(yong)對(dui)鉑(bo)電(dian)(dian)阻(zu)(zu)(zu)斷(duan)續供電(dian)(dian)的方式(shi):即需要(yao)對(dui)某相繞組(zu)溫度測量時, 才給該相的Pt100鉑(bo)電(dian)(dian)阻(zu)(zu)(zu)供電(dian)(dian), 不測量則(ze)不供電(dian)(dian), 減少鉑(bo)電(dian)(dian)阻(zu)(zu)(zu)的工作時間, 延長其使用(yong)壽命;同時也降(jiang)低(di)了(le)通過傳感線(xian)引入溫控器干擾信號強度, 有效提高(gao)溫控器運行的可(ke)靠(kao)性(xing)。

當(dang)然(ran), 高可靠的(de)鉑(bo)電(dian)阻傳感器(qi)也會出(chu)現(xian)個(ge)(ge)別損壞(huai)的(de)現(xian)象(xiang), 為(wei)了(le)保證(zheng)對變(bian)壓(ya)器(qi)繞(rao)組溫度(du)測(ce)量的(de)可靠性及連續性, 核電(dian)溫控(kong)(kong)器(qi)還可采(cai)用(yong)(yong)多余(yu)度(du)溫度(du)采(cai)集(ji)設(she)計:即在(zai)變(bian)壓(ya)器(qi)每個(ge)(ge)低壓(ya)繞(rao)組預(yu)埋兩(liang)條(tiao)Pt100鉑(bo)電(dian)阻傳感器(qi), 一(yi)條(tiao)用(yong)(yong)于主(zhu)測(ce)溫, 另一(yi)條(tiao)備用(yong)(yong);主(zhu)測(ce)溫的(de)Pt100鉑(bo)電(dian)阻與(yu)備用(yong)(yong)Pt100鉑(bo)電(dian)阻各有一(yi)套獨(du)立(li)的(de)測(ce)量電(dian)路, 一(yi)旦主(zhu)測(ce)溫的(de)Pt100鉑(bo)電(dian)阻或其測(ce)量電(dian)路出(chu)故(gu)障, 溫控(kong)(kong)器(qi)通過邏輯判斷, 可自動切除故(gu)障Pt100鉑(bo)電(dian)阻, 啟用(yong)(yong)備用(yong)(yong)Pt100鉑(bo)電(dian)阻測(ce)溫, 確(que)保變(bian)壓(ya)器(qi)始終處于溫控(kong)(kong)器(qi)的(de)保護(hu)下, 保證(zheng)變(bian)壓(ya)器(qi)輸(shu)配(pei)電(dian)的(de)持(chi)續性。

1.3屏蔽(bi)、濾波等抗(kang)干擾措施及內部(bu)雙重邏(luo)輯(ji)控制

溫(wen)(wen)(wen)控(kong)(kong)器(qi)發(fa)(fa)生誤報警(jing)、誤跳(tiao)閘故障(zhang)的(de)原(yuan)因比較復雜, 但一般可歸結為兩類(lei):一類(lei)為溫(wen)(wen)(wen)控(kong)(kong)器(qi)受到外部的(de)強干擾, 使(shi)其(qi)軟(ruan)、硬件系統發(fa)(fa)生紊亂, 引發(fa)(fa)溫(wen)(wen)(wen)控(kong)(kong)器(qi)誤報;另一類(lei)為溫(wen)(wen)(wen)控(kong)(kong)器(qi)的(de)溫(wen)(wen)(wen)度采樣(yang)電路或Pt100鉑電阻傳感器(qi)損壞或漂移, 造(zao)成(cheng)溫(wen)(wen)(wen)度采樣(yang)失真, 引發(fa)(fa)溫(wen)(wen)(wen)控(kong)(kong)器(qi)誤報。

針對外部強(qiang)干擾(rao)引發的(de)誤(wu)報警、誤(wu)跳閘(zha):一方(fang)面(mian)可(ke)通(tong)過(guo)屏(ping)蔽、濾(lv)波的(de)方(fang)式從外部降(jiang)低干擾(rao)的(de)侵(qin)入[4], 核(he)電(dian)(dian)(dian)溫控(kong)器可(ke)采用鐵制(zhi)箱(xiang)體對內(nei)部電(dian)(dian)(dian)路(lu)屏(ping)蔽, 能有(you)效降(jiang)低射(she)頻干擾(rao)信號(hao)的(de)侵(qin)入;核(he)電(dian)(dian)(dian)溫控(kong)器電(dian)(dian)(dian)源電(dian)(dian)(dian)路(lu)中增加(jia)由電(dian)(dian)(dian)容及電(dian)(dian)(dian)感組(zu)成(cheng)的(de)T型濾(lv)波電(dian)(dian)(dian)路(lu), 可(ke)通(tong)過(guo)地線濾(lv)除電(dian)(dian)(dian)源上(shang)(shang)的(de)串(chuan)模(mo)及共(gong)模(mo)干擾(rao)信號(hao)。另一方(fang)面(mian), 在內(nei)部電(dian)(dian)(dian)路(lu)上(shang)(shang)可(ke)采用高(gao)可(ke)靠、抗干擾(rao)能力(li)強(qiang)的(de)AVR芯(xin)片作主(zhu)控(kong)制(zhi)芯(xin)片, 并進(jin)行(xing)合理的(de)電(dian)(dian)(dian)路(lu)板布設, 提高(gao)電(dian)(dian)(dian)路(lu)本身的(de)抗干擾(rao)能力(li)。通(tong)過(guo)上(shang)(shang)述(shu)設計方(fang)法, 可(ke)大(da)幅提高(gao)溫控(kong)器的(de)抗干擾(rao)能力(li), 防(fang)止溫控(kong)器因外部強(qiang)干擾(rao)作用而運(yun)行(xing)紊亂, 失(shi)效, 引發誤(wu)報警、誤(wu)跳閘(zha)。

對于(yu)溫(wen)(wen)控(kong)器(qi)溫(wen)(wen)度(du)采樣失真引發(fa)的(de)(de)(de)(de)誤(wu)(wu)報故(gu)障, 在本文2.2條(tiao)提到的(de)(de)(de)(de)通過(guo)選用(yong)高可靠(kao)的(de)(de)(de)(de)Pt100鉑(bo)電(dian)(dian)(dian)阻及(ji)(ji)采用(yong)主、備測(ce)溫(wen)(wen)方式都(dou)可以(yi)加以(yi)預(yu)防。除此之外(wai), 為進一(yi)步防止誤(wu)(wu)報的(de)(de)(de)(de)發(fa)生, 核(he)電(dian)(dian)(dian)溫(wen)(wen)控(kong)器(qi)還可采用(yong)另(ling)一(yi)種(zhong)PTC熱敏電(dian)(dian)(dian)阻傳感器(qi) (此傳感器(qi)廣泛應用(yong)在電(dian)(dian)(dian)機測(ce)溫(wen)(wen)保護(hu)中) , 用(yong)于(yu)測(ce)量報警點(dian)及(ji)(ji)跳閘點(dian)的(de)(de)(de)(de)溫(wen)(wen)度(du), 該(gai)傳感器(qi)與Pt100鉑(bo)電(dian)(dian)(dian)阻同(tong)樣預(yu)埋在低壓(ya)繞組上(shang)。核(he)電(dian)(dian)(dian)溫(wen)(wen)控(kong)器(qi)結合Pt100主、備測(ce)點(dian)及(ji)(ji)PTC測(ce)點(dian)的(de)(de)(de)(de)信息(xi), 通過(guo)一(yi)系列(lie)的(de)(de)(de)(de)邏輯算法(fa), 可有效地防止誤(wu)(wu)報警、誤(wu)(wu)跳閘的(de)(de)(de)(de)發(fa)生, 對變壓(ya)器(qi)實現Pt100和PTC雙重溫(wen)(wen)度(du)保護(hu)。

核電溫控器的濕度控制功能設計方案

由(you)于核電站一般都是(shi)建在沿海地區, 環(huan)(huan)境空氣(qi)比較潮(chao)(chao)濕, 在變壓(ya)器(qi)(qi)投(tou)運前(qian)或停運后, 都要求對變壓(ya)器(qi)(qi)外殼(ke)內(nei)的(de)環(huan)(huan)境濕度(du)進行控制(zhi), 防止變壓(ya)器(qi)(qi)受(shou)潮(chao)(chao)。核電溫(wen)控器(qi)(qi)可通過專門(men)的(de)環(huan)(huan)境溫(wen)、濕度(du)模塊來(lai)采集變壓(ya)器(qi)(qi)外殼(ke)內(nei)的(de)溫(wen)度(du)及(ji)濕度(du), 在面板上實時顯示, 并可根據用戶預先設(she)定濕度(du)控制(zhi)值, 通過啟動加熱器(qi)(qi)來(lai)調節變壓(ya)器(qi)(qi)外殼(ke)內(nei)的(de)濕度(du)。

部(bu)(bu)分核(he)電(dian)(dian)(dian)(dian)(dian)站(zhan)不提供獨立的(de)(de)(de)外部(bu)(bu)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan), 其變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)直接設(she)計為從(cong)(cong)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)低壓(ya)(ya)(ya)(ya)(ya)(ya)側取(qu)電(dian)(dian)(dian)(dian)(dian)。因(yin)此, 一(yi)旦變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)停運(yun)后, 溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)也停止(zhi)工(gong)作, 將(jiang)直接造(zao)成(cheng)停運(yun)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)濕度失控(kong)(kong)(kong), 變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)受潮(chao)。針對(dui)上(shang)述問(wen)題, 核(he)電(dian)(dian)(dian)(dian)(dian)溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)專門設(she)計了一(yi)個雙電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)切(qie)換(huan)電(dian)(dian)(dian)(dian)(dian)路, 主電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)從(cong)(cong)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)低壓(ya)(ya)(ya)(ya)(ya)(ya)側取(qu)電(dian)(dian)(dian)(dian)(dian), 副電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)從(cong)(cong)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)房(fang)(fang)間的(de)(de)(de)插座(zuo)取(qu)電(dian)(dian)(dian)(dian)(dian) (溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)進行濕度控(kong)(kong)(kong)制時最大(da)功率不超過600 W, 一(yi)般的(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)插座(zuo)的(de)(de)(de)容量是完全可以(yi)滿足的(de)(de)(de)) 。當變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)停運(yun)后, 核(he)電(dian)(dian)(dian)(dian)(dian)溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)自動切(qie)換(huan)到(dao)房(fang)(fang)間插座(zuo)電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)處(chu), 溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)繼續(xu)工(gong)作, 控(kong)(kong)(kong)制濕度, 防止(zhi)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)受潮(chao);一(yi)旦變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)啟(qi)用后, 電(dian)(dian)(dian)(dian)(dian)源(yuan)(yuan)(yuan)(yuan)(yuan)(yuan)又自動切(qie)回到(dao)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)低壓(ya)(ya)(ya)(ya)(ya)(ya)側, 以(yi)確保(bao)變(bian)(bian)(bian)壓(ya)(ya)(ya)(ya)(ya)(ya)器(qi)(qi)(qi)(qi)(qi)(qi)始終處(chu)于溫(wen)控(kong)(kong)(kong)器(qi)(qi)(qi)(qi)(qi)(qi)的(de)(de)(de)監控(kong)(kong)(kong)保(bao)護下(xia)。

3核電溫(wen)控器電路系(xi)統設(she)計

核電(dian)(dian)(dian)溫(wen)控器(qi)電(dian)(dian)(dian)路(lu)如圖1電(dian)(dian)(dian)路(lu)框圖所示, 由雙電(dian)(dian)(dian)源(yuan)切(qie)換電(dian)(dian)(dian)路(lu)、電(dian)(dian)(dian)源(yuan)濾波/整流(liu)/穩壓電(dian)(dian)(dian)路(lu)、主/備Pt100鉑電(dian)(dian)(dian)阻采集(ji)(ji)(ji)電(dian)(dian)(dian)路(lu)、PTC熱敏電(dian)(dian)(dian)阻采集(ji)(ji)(ji)電(dian)(dian)(dian)路(lu)、單片機及存儲電(dian)(dian)(dian)路(lu)、液晶顯(xian)示及鍵盤電(dian)(dian)(dian)路(lu)、環境溫(wen)度(du)(du)/濕(shi)度(du)(du)采集(ji)(ji)(ji)電(dian)(dian)(dian)路(lu)、繼電(dian)(dian)(dian)器(qi)輸出(chu)驅動電(dian)(dian)(dian)路(lu)、溫(wen)度(du)(du)量4~20 m A模擬輸出(chu)電(dian)(dian)(dian)路(lu)、RS-485計算機接(jie)口(kou)電(dian)(dian)(dian)路(lu)構成。

雙電源切換電路

核電(dian)(dian)溫控器(qi)雙電(dian)(dian)源(yuan)切換電(dian)(dian)路(lu)由多個交(jiao)流接觸器(qi)構(gou)成, 具備(bei)電(dian)(dian)路(lu)互鎖(suo)保護(hu), 主、副電(dian)(dian)源(yuan)可靠切換等功能(neng)。同時, 出于用(yong)電(dian)(dian)安全考慮, 在主、副電(dian)(dian)源(yuan)輸入(ru)端都設有空開保護(hu)。

電(dian)源濾(lv)波/變壓/整流/穩壓電(dian)路

(1) 核電(dian)(dian)溫(wen)控器在電(dian)(dian)源輸入端設(she)計有金屬膜安規(gui)電(dian)(dian)容(rong)、陶瓷電(dian)(dian)容(rong)及電(dian)(dian)感組(zu)成(cheng)的T型濾(lv)波電(dian)(dian)路。

(2) 專門(men)設置有(you)地線接入口, 保證可(ke)靠接地。同時, 采用電(dian)源(yuan)變壓器隔離降壓, 電(dian)源(yuan)變壓器外殼接地。

(3) 采用(yong)高耐(nai)壓(ya)大功(gong)率二極管組成(cheng)的整流(liu)(liu)電(dian)路將電(dian)源變壓(ya)器輸出(chu)的交(jiao)流(liu)(liu)電(dian)源整流(liu)(liu)成(cheng)直(zhi)流(liu)(liu)后(hou), 經(jing)穩壓(ya)模(mo)塊穩壓(ya)成(cheng)穩定的直(zhi)流(liu)(liu)給(gei)主板上(shang)各(ge)功(gong)能模(mo)塊供電(dian)。

3.3主/備Pt100鉑電阻溫度采集電路

(1) 采用(yong)四線(xian)制Pt100鉑電阻(zu)測(ce)溫技術, 由恒(heng)流源及模(mo)擬開關實(shi)現Pt100鉑電阻(zu)輪流供電及溫度采樣(yang)。

(2) 采用高(gao)精度A/D轉換(huan)器, 對溫度信號(hao)實現(xian)高(gao)精度模(mo)數(shu)轉換(huan)。

3.4 PTC熱敏電阻溫度(du)采(cai)集電路

由電(dian)阻及運放(fang)等元器件組成, 利用(yong)PTC140及PTC150熱敏電(dian)阻分別(bie)在超溫(wen)(wen)報警溫(wen)(wen)度(du)(du)點、超溫(wen)(wen)跳閘溫(wen)(wen)度(du)(du)點電(dian)阻突變(bian)的特性, 可有效(xiao)捕捉(zhuo)到超溫(wen)(wen)報警溫(wen)(wen)度(du)(du)點及超溫(wen)(wen)跳閘溫(wen)(wen)度(du)(du)點, 并(bing)結合Pt100的測溫(wen)(wen)結果, 對變(bian)壓(ya)器實現雙重溫(wen)(wen)度(du)(du)保護(hu)。

單片機及存儲電路

新型核(he)電(dian)溫控器(qi)選用Atmel公司(si)生產的(de)AVR芯(xin)片(pian)作為主控芯(xin)片(pian), 該(gai)芯(xin)片(pian)抗(kang)干擾能力極強(qiang)(qiang), 內(nei)置(zhi)功能強(qiang)(qiang)大, 有8路10位A/D轉換(huan)器(qi)、兩路通訊口(kou)、8路PMW發(fa)生器(qi)、64K程序(xu)存儲器(qi), 64K數據(ju)存儲器(qi)等。該(gai)芯(xin)片(pian)目前廣(guang)泛應用在工業(ye)控制領(ling)域(yu)。

液晶顯示及鍵盤電路

(1) 顯示電路采用(yong)大屏幕液晶(jing)顯示屏, 可同(tong)時顯示各繞組(zu)的溫度及環境濕度, 顯示界(jie)面清淅、明確、直(zhi)觀, 具有使用(yong)壽(shou)命(ming)長, 穩(wen)定性高(gao)等(deng)特點。

(2) 按(an)鍵(jian)采用輕觸按(an)鍵(jian), 可方便地設定和(he)查尋數據。

環(huan)境溫度(du)/濕(shi)度(du)采集電路

采用(yong)專用(yong)的(de)環境溫(wen)(wen)度(du)/濕度(du)測量(liang)模塊, 可(ke)準(zhun)確地測量(liang)周圍環境的(de)溫(wen)(wen)度(du)及濕度(du)。

繼電器輸出驅動電路

(1) 采用(yong)總(zong)線控制器及繼(ji)電器功(gong)率(lv)驅(qu)動芯片組成(cheng)繼(ji)電器驅(qu)動電路, 抗干(gan)擾能力(li)強。

(2) 繼(ji)電器功(gong)率芯片(pian)有8路輸出, 最大每路驅(qu)動能力(li)達(da)500 m A, 可實現(xian)超(chao)溫報警、超(chao)溫跳閘、故障等無(wu)源接點輸出, 接點容量為(wei)2A/110VDC。

(3) 輸出風(feng)機及加(jia)熱(re)器(qi)有(you)源接點, 控制風(feng)機及加(jia)熱(re)器(qi)啟停, 以達到降溫或除濕目的。

RS-485計算機接口電(dian)路及溫(wen)度量4~20 m A模擬輸出電(dian)路

采用光耦(ou)和MAX485芯片構(gou)成計算機接口電(dian)路(lu)(lu), 溫控(kong)(kong)器可將各(ge)相溫度值、繼電(dian)器狀態等信息通(tong)過(guo)此(ci)接口上傳到用戶的主控(kong)(kong)計算機中(zhong), 并與外部(bu)通(tong)訊(xun)電(dian)路(lu)(lu)光電(dian)隔離。

采用高精度D/A轉換器及(ji)(ji)運放及(ji)(ji)三(san)級管組(zu)成的4~20 m A模擬輸(shu)(shu)出(chu)電(dian)路, 每路4~20 m A輸(shu)(shu)出(chu)電(dian)路最大負載大于300Ω。

核電(dian)(dian)(dian)溫(wen)(wen)控(kong)器在常規溫(wen)(wen)控(kong)器電(dian)(dian)(dian)路(lu)(lu)設(she)計的基礎(chu)上, 采(cai)用(yong)了新型高精度溫(wen)(wen)度采(cai)集電(dian)(dian)(dian)路(lu)(lu), 選用(yong)了抗(kang)干擾(rao)能(neng)力強的主控(kong)芯片(pian), 增加(jia)了濕度測(ce)量/控(kong)制及PTC測(ce)溫(wen)(wen)電(dian)(dian)(dian)路(lu)(lu), 使(shi)其無論在功能(neng)、性能(neng)及可靠性方面都較常規溫(wen)(wen)控(kong)器有較大(da)的提高。

核電(dian)干(gan)式(shi)變(bian)壓(ya)器(qi)(qi)用溫(wen)度控(kong)(kong)制(zhi)器(qi)(qi), 是在分(fen)析、總(zong)結常(chang)規干(gan)式(shi)變(bian)壓(ya)器(qi)(qi)溫(wen)控(kong)(kong)器(qi)(qi)可靠(kao)性(xing)薄弱(ruo)環節的(de)(de)基礎上(shang), 嚴格按照機械(xie)工業(ye)部(bu)標準JB/T7631-2005《變(bian)壓(ya)器(qi)(qi)用電(dian)子溫(wen)控(kong)(kong)器(qi)(qi)》和電(dian)磁兼(jian)容標準JB/T17626《電(dian)磁兼(jian)容試(shi)驗和測量技術》的(de)(de)要求設計(ji)的(de)(de)。核電(dian)溫(wen)控(kong)(kong)器(qi)(qi)采用了(le)(le)新(xin)的(de)(de)設計(ji)思路、甄選了(le)(le)新(xin)型(xing)材料、擴展(zhan)了(le)(le)新(xin)型(xing)功能, 有效(xiao)地提高其性(xing)能及(ji)運行可靠(kao)性(xing)。

當然, 從本質上講, 核(he)電溫控器只是一款帶濕度控制的(de)(de)變壓器溫度控制器, 為適應(ying)今后儀表(biao)智能(neng)化(hua)(hua)(hua)、網絡化(hua)(hua)(hua)、無線化(hua)(hua)(hua)發展(zhan)要(yao)求的(de)(de), 還可以發展(zhan)以下一些(xie)擴(kuo)展(zhan)功能(neng), 進一步(bu)提升其整體性(xing)能(neng):

(1) 測量變(bian)壓(ya)(ya)(ya)(ya)器高、低壓(ya)(ya)(ya)(ya)側的電壓(ya)(ya)(ya)(ya)、電流(liu), 進行電能(neng)管理, 計(ji)算變(bian)壓(ya)(ya)(ya)(ya)器效率, 統(tong)計(ji)變(bian)壓(ya)(ya)(ya)(ya)器的負荷(he)曲線, 為用(yong)戶(hu)高效使用(yong)變(bian)壓(ya)(ya)(ya)(ya)器提供技術方案;

(2) 記錄變壓器溫度(du)數據, 并根(gen)據《變壓器負載導則》的要求計算變壓器剩余(yu)使用壽命, 方(fang)便用戶查尋;

(3) 根據(ju)變(bian)壓器(qi)維護要求, 到(dao)期(qi)提醒用戶進行變(bian)壓器(qi)保養維護;

(4) 利用成熟的(de)互聯網(wang)技術, 增加以太網(wang)接口、無線網(wang)絡(luo)接口, 實現儀表的(de)網(wang)絡(luo)化。

通(tong)過上述(shu)功(gong)能(neng)的(de)擴展, 核電溫控(kong)(kong)器最終可轉變為綜(zong)合功(gong)能(neng)強大(da)的(de)變壓(ya)器智能(neng)控(kong)(kong)制器, 進而實現干(gan)式變壓(ya)器的(de)智能(neng)化、網絡化。