內蒙古國華準(zhun)電(dian)公(gong)司三(san)(san)、四號機(ji)組(zu)主變(bian)(bian)(bian)(bian)、廠(chang)(chang)變(bian)(bian)(bian)(bian)采(cai)用的是特(te)變(bian)(bian)(bian)(bian)電(dian)工沈陽變(bian)(bian)(bian)(bian)壓(ya)器(qi)(qi)集團(tuan)產品。主變(bian)(bian)(bian)(bian)500k V三(san)(san)相雙繞(rao)(rao)組(zu)強迫(po)導向油循(xun)環風(feng)冷油浸式升壓(ya)變(bian)(bian)(bian)(bian)壓(ya)器(qi)(qi)、廠(chang)(chang)變(bian)(bian)(bian)(bian)采(cai)用的是24k V三(san)(san)相自然油循(xun)環風(feng)冷分裂繞(rao)(rao)組(zu)廠(chang)(chang)用工作變(bian)(bian)(bian)(bian)壓(ya)器(qi)(qi)。該(gai)型號主變(bian)(bian)(bian)(bian)及廠(chang)(chang)變(bian)(bian)(bian)(bian)運行穩(wen)定可靠, 主變(bian)(bian)(bian)(bian)壓(ya)器(qi)(qi)配(pei)(pei)置(zhi)兩組(zu)油面溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)和一(yi)(yi)組(zu)繞(rao)(rao)組(zu)溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)。廠(chang)(chang)變(bian)(bian)(bian)(bian)配(pei)(pei)置(zhi)一(yi)(yi)組(zu)油面溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)和一(yi)(yi)組(zu)繞(rao)(rao)組(zu)溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)。溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)通過Pt鉑電(dian)阻輸(shu)出送(song)至DCS系(xi)統DCS系(xi)統通過測量顯(xian)示(shi)變(bian)(bian)(bian)(bian)壓(ya)器(qi)(qi)溫(wen)(wen)度(du)(du), 隨著原溫(wen)(wen)控(kong)制(zhi)老化及原設備廠(chang)(chang)家停產更新設備等因素, 更換(huan)的新溫(wen)(wen)控(kong)器(qi)(qi)存(cun)在(zai)就地(di)輸(shu)出與DCS系(xi)統顯(xian)示(shi)存(cun)在(zai)偏差及就地(di)指(zhi)針指(zhi)示(shi)不準(zhun)確的問題(ti)。經過研究發現該(gai)問題(ti)與溫(wen)(wen)控(kong)器(qi)(qi)產品更新有(you)關, 本文著重對(dui)該(gai)問題(ti)進(jin)行簡要(yao)分析。

1 配置情況

主變壓器(qi)配置兩組油面溫(wen)(wen)度(du)(du)控(kong)制(zhi)(zhi)器(qi)和一組繞組溫(wen)(wen)度(du)(du)控(kong)制(zhi)(zhi)器(qi)。廠變配置一組油面溫(wen)(wen)度(du)(du)控(kong)制(zhi)(zhi)器(qi)和一組繞組溫(wen)(wen)度(du)(du)控(kong)制(zhi)(zhi)器(qi)。溫(wen)(wen)度(du)(du)控(kong)制(zhi)(zhi)器(qi)通過Pt鉑電阻輸出送至(zhi)DCS系統(tong), 溫(wen)(wen)度(du)(du)監控(kong)運(yun)行可(ke)靠(kao), 對(dui)溫(wen)(wen)度(du)(du)上升及突變均能(neng)很好反應, 保障變壓器(qi)的安全穩定運(yun)行。

2 發現及解決問題

2014年1月(yue)電氣(qi)人員(yuan)對(dui)(dui)溫(wen)度(du)控制器(qi)(qi)進(jin)行(xing)校驗, 校驗中發(fa)現(xian)(xian)15m溫(wen)控器(qi)(qi)指(zhi)(zhi)示(shi)溫(wen)度(du)與Pt鉑(bo)電阻表指(zhi)(zhi)示(shi)值(zhi)存在10℃偏(pian)差(cha), 立(li)即(ji)聯(lian)系廠(chang)家(jia)人員(yuan), 廠(chang)家(jia)人員(yuan)解釋(shi), 溫(wen)控器(qi)(qi)輸(shu)出(chu)采用Pt鉑(bo)電阻三(san)線(xian)制, 接入DCS系統后會自動屏蔽接線(xian)長(chang)度(du)滿足(zu)運行(xing)要(yao)求, 可以使用。多數廠(chang)家(jia)使用未發(fa)現(xian)(xian)異常(chang), 隨后對(dui)(dui)四(si)號機主變壓(ya)器(qi)(qi)溫(wen)度(du)控制進(jin)行(xing)更(geng)換(huan)(huan), 更(geng)換(huan)(huan)后發(fa)現(xian)(xian)DCS系統顯示(shi)變壓(ya)器(qi)(qi)溫(wen)度(du)與就地溫(wen)控器(qi)(qi)指(zhi)(zhi)示(shi)偏(pian)差(cha)3℃, 滿足(zu)誤差(cha)要(yao)求。繼續(xu)更(geng)換(huan)(huan)四(si)號機組廠(chang)變溫(wen)度(du)控制器(qi)(qi), 更(geng)換(huan)(huan)后溫(wen)度(du)DCS系統顯示(shi)變壓(ya)器(qi)(qi)溫(wen)度(du)與就地溫(wen)控器(qi)(qi)指(zhi)(zhi)示(shi)偏(pian)差(cha)2.5℃左右(you)也滿足(zu)要(yao)求。安裝完(wan)成, 隨著運行(xing)溫(wen)度(du)計室外環境的(de)變化出(chu)現(xian)(xian)如下(xia)問題, 異常(chang)記(ji)錄數據如下(xia)。

(1) 變壓器溫控器指(zhi)針(zhen)經常卡澀, 冬(dong)季溫度低時尤(you)為明顯(xian)。

(2) 變壓器溫控(kong)器就地指示與(yu)DCS偏差(cha)較(jiao)大, 并且不是恒(heng)定數值, 低溫時偏差(cha)顯著。

(3) 新產(chan)品油(you)(you)(you)面溫(wen)(wen)控(kong)(kong)器(qi)與(yu)(yu)老產(chan)品 (三(san)號機組(zu)部(bu)分(fen)在(zai)用(yong)) 比較, 新產(chan)品與(yu)(yu)標準(zhun)Pt電阻(zu)(zu)(zu)(zu)對(dui)應(ying)表(biao)存在(zai)誤差, 對(dui)應(ying)不(bu)上(shang), (溫(wen)(wen)控(kong)(kong)器(qi)公共線間(jian)存在(zai)約4.3Ω內(nei)(nei)(nei)阻(zu)(zu)(zu)(zu), 三(san)號機在(zai)用(yong)老溫(wen)(wen)控(kong)(kong)器(qi)內(nei)(nei)(nei)阻(zu)(zu)(zu)(zu)在(zai)2.1Ω左(zuo)右) 存在(zai)誤差, 廠家(jia)提供油(you)(you)(you)面溫(wen)(wen)控(kong)(kong)器(qi), 測(ce)量電阻(zu)(zu)(zu)(zu)與(yu)(yu)溫(wen)(wen)度(du)(du)對(dui)應(ying)關系(xi)需要(yao)用(yong)計算公式(shi)確(que)定(ding)溫(wen)(wen)度(du)(du), 實際測(ce)量內(nei)(nei)(nei)阻(zu)(zu)(zu)(zu)在(zai)4.5~2.3Ω間(jian)變(bian)化(hua), 因溫(wen)(wen)控(kong)(kong)器(qi)內(nei)(nei)(nei)阻(zu)(zu)(zu)(zu)變(bian)化(hua)不(bu)確(que)定(ding), DCS系(xi)統無法補償修正, 不(bu)能(neng)正常顯(xian)示(shi)變(bian)壓器(qi)溫(wen)(wen)度(du)(du), 不(bu)能(neng)正常監視變(bian)壓器(qi)油(you)(you)(you)面實際溫(wen)(wen)度(du)(du)。

(4) 具體溫(wen)度偏差(cha)如表1: (變(bian)壓器(qi)運行(xing), 繞組溫(wen)控(kong)器(qi)公(gong)共(gong)線間內(nei)阻變(bian)化不確定)

3 解決方法及分析

通過(guo)對(dui)主變(bian)油面溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)數(shu)據進行(xing)對(dui)比(bi)(bi)發現(xian)(xian)偏差(cha)(cha)不恒定(ding)(ding)(ding), 實際測(ce)量溫(wen)(wen)控(kong)器(qi)(qi)公(gong)共端電阻(zu)也經常變(bian)化, 初(chu)步確定(ding)(ding)(ding)產品升級后不滿足現(xian)(xian)場需求, 經過(guo)對(dui)比(bi)(bi)以前的(de)老(lao)產品, 發現(xian)(xian)根本原(yuan)(yuan)因(yin)是溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)內(nei)阻(zu)的(de)增加和不恒定(ding)(ding)(ding)導(dao)致溫(wen)(wen)度(du)(du)偏差(cha)(cha)。對(dui)比(bi)(bi)及(ji)檢查現(xian)(xian)場溫(wen)(wen)度(du)(du)控(kong)制(zhi)器(qi)(qi)安裝方(fang)式及(ji)設(she)備測(ce)點位(wei)置(zhi), 發現(xian)(xian)主要(yao)原(yuan)(yuan)因(yin)是溫(wen)(wen)控(kong)器(qi)(qi)升級后在毛(mao)細管(guan)超過(guo)10m后精(jing)度(du)(du)達不到原(yuan)(yuan)來老(lao)產品的(de)精(jing)度(du)(du)誤差(cha)(cha)隨內(nei)阻(zu)變(bian)化而變(bian)化, 導(dao)致溫(wen)(wen)度(du)(du)不穩定(ding)(ding)(ding)和DCS系統顯示數(shu)據偏差(cha)(cha), 不能滿足現(xian)(xian)場需求。為(wei)了(le)更好(hao)的(de)解(jie)決(jue)(jue)現(xian)(xian)場存在的(de)問題重點從兩方(fang)面解(jie)決(jue)(jue)。 (1) 更換優(you)質的(de)溫(wen)(wen)控(kong)器(qi)(qi)解(jie)決(jue)(jue)指針卡澀問題; (2) 新(xin)購溫(wen)(wen)控(kong)器(qi)(qi), 安裝位(wei)置(zhi)采(cai)用就(jiu)近測(ce)點位(wei)置(zhi)安裝, 減少(shao)(shao)毛(mao)細管(guan)長(chang)度(du)(du), 毛(mao)細管(guan)長(chang)度(du)(du)由15m變(bian)為(wei)8m, 減少(shao)(shao)誤差(cha)(cha)和提高精(jing)度(du)(du)。

通(tong)過上述辦法, 更換新型號的溫度控制器后, 觀察變壓(ya)器溫度控制器與(yu)DCS系統(tong)偏(pian)差在1度左右(you), 滿(man)足(zu)偏(pian)差要(yao)求(qiu), 滿(man)足(zu)運行要(yao)求(qiu)。

4 結束語

通(tong)過對變(bian)壓(ya)器(qi)(qi)(qi)溫(wen)(wen)度控(kong)(kong)制存在(zai)問題的(de)(de)(de)分析及解決, 可以(yi)看出(chu)設(she)備升(sheng)級后型號與現(xian)場(chang)設(she)備有時因不滿足現(xian)場(chang)要(yao)求(qiu), 溫(wen)(wen)控(kong)(kong)器(qi)(qi)(qi)公(gong)共(gong)端內(nei)阻(zu)到達4.3Ω左(zuo)右, 加上(shang)變(bian)壓(ya)器(qi)(qi)(qi)溫(wen)(wen)控(kong)(kong)器(qi)(qi)(qi)接線端子箱至熱控(kong)(kong)機柜電纜(lan)電阻(zu), 有時就超過DCS系統(tong)測量的(de)(de)(de)極(ji)限, 造成精(jing)度超差而顯示誤差增(zeng)大(da), 當內(nei)阻(zu)降到2.2左(zuo)右時又符合要(yao)求(qiu), 造成溫(wen)(wen)度偏(pian)差較小。廠(chang)家人員(yuan)堅持自己的(de)(de)(de)個人觀點(dian), 認(ren)為通(tong)過自己的(de)(de)(de)公(gong)式計算符合要(yao)求(qiu)就沒問題, 這樣導致DCS系統(tong)無法適(shi)應原型號的(de)(de)(de)升(sheng)級產(chan)品。變(bian)壓(ya)器(qi)(qi)(qi)是發電廠(chang)的(de)(de)(de)重要(yao)設(she)備, 對負責監視變(bian)壓(ya)器(qi)(qi)(qi)溫(wen)(wen)度運行(xing)狀態的(de)(de)(de)溫(wen)(wen)控(kong)(kong)器(qi)(qi)(qi), 進行(xing)及時更換和異常的(de)(de)(de)分析處理非常必要(yao)。