簡要(yao)描(miao)述:概述:電壓互感器二次回(hui)路壓降測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)方法(fa)(fa)通常有(you)間(jian)接測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)和直接測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)兩(liang)種(無線測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)屬于(yu)間(jian)接測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)),由于(yu)間(jian)接測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)準確度不(bu)太高,不(bu)能滿(man)足測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)要求,般不(bu)采(cai)用此(ci)種方法(fa)(fa),而直接測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(校驗儀測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa))采(cai)用測(ce)(ce)(ce)(ce)(ce)差原(yuan)理,準確度高,測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)可靠,因此(ci)在實際(ji)測(ce)(ce)(ce)(ce)(ce)量(liang)(liang)(liang)中大量(liang)(liang)(liang)采(cai)用。
概述:
電壓互感器二次回路壓降測(ce)(ce)(ce)量(liang)(liang)(liang)方(fang)法(fa)(fa)(fa)通常有間(jian)接(jie)(jie)(jie)測(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(fa)和直(zhi)接(jie)(jie)(jie)測(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(fa)兩(liang)種(無(wu)線測(ce)(ce)(ce)量(liang)(liang)(liang)屬于間(jian)接(jie)(jie)(jie)測(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(fa)),由于間(jian)接(jie)(jie)(jie)測(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(fa)準確度不太高(gao)(gao),不能(neng)滿足測(ce)(ce)(ce)量(liang)(liang)(liang)要(yao)求,般不采用(yong)此(ci)(ci)種方(fang)法(fa)(fa)(fa),而直(zhi)接(jie)(jie)(jie)測(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(fa)(校驗(yan)儀測(ce)(ce)(ce)量(liang)(liang)(liang)法(fa)(fa)(fa))采用(yong)測(ce)(ce)(ce)差原理,準確度高(gao)(gao),測(ce)(ce)(ce)量(liang)(liang)(liang)可靠(kao),因此(ci)(ci)在(zai)實際(ji)測(ce)(ce)(ce)量(liang)(liang)(liang)中大量(liang)(liang)(liang)采用(yong)。
產(chan)品詳細描(miao)述(shu):
電(dian)(dian)能(neng)計(ji)量(liang)裝置存(cun)在的(de)誤(wu)(wu)差為電(dian)(dian)能(neng)計(ji)量(liang)綜合(he)(he)誤(wu)(wu)差,是由電(dian)(dian)能(neng)表的(de)誤(wu)(wu)差、電(dian)(dian)壓互(hu)感(gan)器的(de)合(he)(he)成誤(wu)(wu)差、電(dian)(dian)流互(hu)感(gan)器的(de)合(he)(he)成誤(wu)(wu)差和電(dian)(dian)壓互(hu)感(gan)器二次導線壓降引起的(de)計(ji)量(liang)誤(wu)(wu)差所組成,可以用以下(xia)式子表示(shi):
ε=εw+εTA+εTV+εr
式中 εw—電能(neng)表誤(wu)差%
εTA—電流互感(gan)器合成誤(wu)差%
εTV—電(dian)壓(ya)互感器合成誤差%
εr—電壓(ya)互感(gan)器二次導線壓(ya)降引(yin)起的計量(liang)誤差%
在電(dian)(dian)(dian)(dian)(dian)(dian)(dian)廠(chang)及變(bian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)站電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)計量回路中,室(shi)外(wai)的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)互感(gan)器離(li)裝設于控制(zhi)室(shi)配(pei)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)盤上的(de)(de)(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)表有(you)(you)較遠的(de)(de)(de)(de)距離(li),般(ban)在200~400 m左右,整個回路有(you)(you)接(jie)線端(duan)子(zi)排、開關、熔斷(duan)器及導線,必然存(cun)在著接(jie)觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻、導線電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻及分布參數,從而就存(cun)在著定(ding)的(de)(de)(de)(de)回路阻抗,造成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)互感(gan)器與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)表間(jian)的(de)(de)(de)(de)二(er)(er)次回路上有(you)(you)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)互感(gan)器二(er)(er)次回路壓(ya)降(jiang)包括(kuo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜、端(duan)子(zi)接(jie)觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻、熔線、中間(jian)繼電(dian)(dian)(dian)(dian)(dian)(dian)(dian)器接(jie)點、空氣小開關等電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)之(zhi)總(zong)和(he)。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)互感(gan)器二(er)(er)次電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)降(jiang)引(yin)起的(de)(de)(de)(de)誤差(cha)(cha)(cha),就是指電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)互感(gan)器二(er)(er)次端(duan)子(zi)和(he)負(fu)載(zai)端(duan)子(zi)之(zhi)間(jian)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)幅值差(cha)(cha)(cha)相對于二(er)(er)次實(shi)際電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)的(de)(de)(de)(de)百分數,以及兩個電(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)之(zhi)間(jian)的(de)(de)(de)(de)相位差(cha)(cha)(cha)的(de)(de)(de)(de)總(zong)稱。
《電能計量裝置技術管理規程》DL/T448-2000的規定,電壓互感器二次回路壓降,對于I類計量裝置,應不大于額定二次電壓的0.2%(注:三相三線電路壓降的允許值為0.2 V;三相四線電路壓降允許值為0.2/V);其它計量裝置,應不大于額定二次電壓的0.5%(注:三相三線電路壓降的允許值為0.5 V;三相四線電路壓降允許值為0.5/V)。對運行(xing)(xing)中的電(dian)(dian)壓互感器(qi)二次回路壓降需進(jin)行(xing)(xing)周(zhou)期測試,以(yi)便算出由此引起的電(dian)(dian)能計(ji)量誤差(cha),這對于進(jin)行(xing)(xing)技術改進(jin),減小(xiao)電(dian)(dian)能計(ji)量綜合誤差(cha),降低計(ji)費(fei)損失有著重要意(yi)義(yi)
電壓(ya)互感器二次回路壓(ya)降測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)方法通常有間(jian)接(jie)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)法和直(zhi)接(jie)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)法兩種(zhong)(無(wu)線測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)屬于(yu)間(jian)接(jie)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)法),由(you)于(yu)間(jian)接(jie)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)法準(zhun)確度(du)不(bu)太高,不(bu)能(neng)滿足(zu)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)要求,般不(bu)采用(yong)此種(zhong)方法,而直(zhi)接(jie)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)法(校驗儀(yi)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)法)采用(yong)測(ce)(ce)(ce)(ce)差原理,準(zhun)確度(du)高,測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)可靠(kao),因此在實際(ji)測(ce)(ce)(ce)(ce)量(liang)(liang)(liang)(liang)(liang)中大量(liang)(liang)(liang)(liang)(liang)采用(yong)。
二次壓降對互感器誤差影響說明請參考下圖。
電流互(hu)感器(qi)的負(fu)荷特性曲線
電壓(ya)互感器電壓(ya)與(yu)負荷特性
目(mu)前(qian)對互(hu)感器(qi)(qi)誤(wu)差測(ce)試時(shi),通常(chang)按互(hu)感器(qi)(qi)銘牌上(shang)的規定(ding)(ding)用電(dian)(dian)流(liu)負(fu)(fu)荷(he)箱和電(dian)(dian)壓(ya)負(fu)(fu)荷(he)箱對互(hu)感器(qi)(qi)進(jin)行測(ce)試,但互(hu)感器(qi)(qi)運行過程中(zhong)實際(ji)二次負(fu)(fu)荷(he)是(shi)多(duo)少?是(shi)不是(shi)就(jiu)是(shi)互(hu)感器(qi)(qi)銘牌上(shang)規定(ding)(ding)值?互(hu)感器(qi)(qi)在實際(ji)二次負(fu)(fu)荷(he)下的誤(wu)差是(shi)多(duo)少?
為了解決上(shang)述問題,實際測試互感(gan)器(qi)二(er)次(ci)(ci)負荷(he)就顯(xian)得特別(bie)重(zhong)要。同時(shi)(shi)在測試實際二(er)次(ci)(ci)負荷(he)過程中如(ru)何取樣電流(liu)信(xin)號也(ye)是比較重(zhong)要的問題。在測試現場二(er)次(ci)(ci)負荷(he)時(shi)(shi)停電斷開電流(liu)回(hui)路既不(bu)方便(bian)也(ye)不(bu)安全。我公司產(chan)品采用鉗型電流(liu)互感(gan)器(qi)(鉗表)對線路電流(liu)進行采樣,方便(bian)用戶使用。
另外有(you)些公(gong)司(si)產品采用取PT電壓(ya)作(zuo)為儀(yi)(yi)器(qi)(qi)(qi)工(gong)作(zuo)電源,這(zhe)種方(fang)式(shi)不(bu)是很(hen)安(an)(an)全(quan)(quan),在(zai)這(zhe)種方(fang)式(shi)下,相當于給PT/CT增加了負荷(he),同(tong)時儀(yi)(yi)器(qi)(qi)(qi)變壓(ya)器(qi)(qi)(qi)的瞬間激磁電流很(hen)可能(neng)引(yin)起系(xi)統(tong)保護動作(zuo),影響(xiang)供(gong)電安(an)(an)全(quan)(quan)。我公(gong)司(si)儀(yi)(yi)器(qi)(qi)(qi)采用大容量鋰(li)電池作(zuo)為儀(yi)(yi)器(qi)(qi)(qi)工(gong)作(zuo)電源,既可以保障系(xi)統(tong)安(an)(an)全(quan)(quan)又可以給儀(yi)(yi)器(qi)(qi)(qi)提供(gong)比較純凈的電源,避(bi)免現場(chang)電源干擾,保證測(ce)量精度(du)。
二次(ci)壓降(jiang)測試(shi)儀具(ju)有下列功能(neng)
⑴ 可以實現三(san)(san)(san)相(xiang)(xiang)三(san)(san)(san)線,三(san)(san)(san)相(xiang)(xiang)四(si)線、單相(xiang)(xiang)全(quan)自動測量;
⑵ 使用工程(cheng)塑料機箱,結識耐(nai)用,有(you)效保障(zhang)測試人(ren)員及系統安全(quan);
⑶ 儀器具有量程自動切換功能,保證測試(shi)精度(du);
⑷ 采用電子式原(yuan)理線路結合DSP技術(shu)是使測(ce)試穩(wen)定性好(hao),抗(kang)干(gan)擾能力(li)強;
⑸ 測量完畢(bi),自(zi)動計(ji)算和負荷相關的各項參數,便于客(ke)戶分析和試驗。
⑹采(cai)用大(da)屏幕漢(han)字液晶顯(xian)示,所有操(cao)作均由漢(han)字菜單提示; 數(shu)據(ju)(ju)具備掉(diao)電存貯及瀏覽功能(neng),能(neng)與計算機(ji)聯機(ji)傳(chuan)送數(shu)據(ju)(ju)。
⑺采用大容量7.2V11Ah鋰(li)電(dian)池供電(dian),對測(ce)試回(hui)路不產生任何影響,避免系(xi)統(tong)出現(xian)保護的情況。同時在(zai)現(xian)場無供電(dian)電(dian)源的情況下使用。
停電在線測量(liang)(liang)。自動切換量(liang)(liang)程(cheng):測量(liang)(liang)過程(cheng)中可以根據測試對象(xiang)數值的不同切
換到(dao)不同的位(wei)置,使(shi)測量精度(du)和顯示位(wei)數得到(dao)保證。
⒁ 中文界(jie)面(mian)大屏幕顯示(shi),帶有(you)RS-232通訊接口
技(ji)術指(zhi)標
、環境條件
溫度:-5℃~40℃
相對濕度:<95%(25℃)
海拔高度(du):<2500mm
外界(jie)干擾:無特(te)強震動、無特(te)強電磁場(chang)
二、二次壓降(jiang)測試(shi)時儀器主要技(ji)術指(zhi)標(biao)
⊙量(liang)范(fan)圍:比差:0.001%~19.99% 角差:0.01′~599′
⊙辨率:比差:0.001% 角差:0.01′
⊙儀器基本誤差
DX=( X×2%+ Y×2%)±2個字;
DY=( Y×2%+ X×2%×34.38)±2個字
2個(ge)字(zi)——儀器的量化誤差
⊙電壓表頭準確度(du):0.5%
⊙工作范圍
電壓:(50~120)V
⊙儀器指示動作值
誤差:比差大(da)于20%或(huo)角差大(da)于600′
電壓:<2.0V