一、二次(ci)（PT）壓(ya)降測試儀產(chan)品簡介

電(dian)能(neng)計量裝置存在的誤(wu)(wu)(wu)差(cha)(cha)為電(dian)能(neng)計量綜(zong)合(he)誤(wu)(wu)(wu)差(cha)(cha)，是由電(dian)能(neng)表(biao)的誤(wu)(wu)(wu)差(cha)(cha)、電(dian)壓(ya)互(hu)感(gan)器(qi)的合(he)成誤(wu)(wu)(wu)差(cha)(cha)、電(dian)流互(hu)感(gan)器(qi)的合(he)成誤(wu)(wu)(wu)差(cha)(cha)和電(dian)壓(ya)互(hu)感(gan)器(qi)二次導線壓(ya)降引起的計量誤(wu)(wu)(wu)差(cha)(cha)所組成，可(ke)以用以下(xia)式子表(biao)示：

ε=εw＋εTA＋εTV＋εr

式中    εw—電能表誤差%

εTA—電(dian)流互感器合成誤(wu)差%

εTV—電壓互感器(qi)合(he)成誤差%

εr—電壓互感器二(er)次導(dao)線壓降引起的計(ji)量(liang)誤差%

在(zai)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)廠及變電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)站電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)計量回(hui)(hui)路(lu)中(zhong)，室外(wai)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)互感器(qi)(qi)離裝(zhuang)設于(yu)控制(zhi)室配電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)盤(pan)上(shang)的(de)(de)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)表(biao)有較遠的(de)(de)距(ju)離，一般在(zai)200～400 m左右，整個(ge)回(hui)(hui)路(lu)有接(jie)線端(duan)子排、開(kai)關、熔(rong)斷器(qi)(qi)及導線，必然存在(zai)著接(jie)觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻、導線電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻及分布參數，從(cong)而就(jiu)(jiu)存在(zai)著一定的(de)(de)回(hui)(hui)路(lu)阻抗，造成電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)互感器(qi)(qi)與電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)能(neng)表(biao)間的(de)(de)二(er)(er)(er)次(ci)(ci)(ci)回(hui)(hui)路(lu)上(shang)有電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)降。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)互感器(qi)(qi)二(er)(er)(er)次(ci)(ci)(ci)回(hui)(hui)路(lu)壓(ya)(ya)(ya)(ya)(ya)降包括(kuo)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)纜、端(duan)子接(jie)觸電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)阻、熔(rong)線、中(zhong)間繼電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)器(qi)(qi)接(jie)點(dian)、空氣小開(kai)關等(deng)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)降之(zhi)(zhi)總和。電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)互感器(qi)(qi)二(er)(er)(er)次(ci)(ci)(ci)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)降引起的(de)(de)誤差，就(jiu)(jiu)是(shi)指(zhi)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)互感器(qi)(qi)二(er)(er)(er)次(ci)(ci)(ci)端(duan)子和負載(zai)端(duan)子之(zhi)(zhi)間電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)的(de)(de)幅值(zhi)差相對于(yu)二(er)(er)(er)次(ci)(ci)(ci)實際電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)的(de)(de)百分數，以及兩個(ge)電(dian)(dian)(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)(ya)之(zhi)(zhi)間的(de)(de)相位差的(de)(de)總稱。

《電(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)計量(liang)裝置技(ji)術管理規程》DL／T448－2000的規定，電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)互感器(qi)二(er)次(ci)回路(lu)壓(ya)(ya)(ya)降(jiang)(jiang)(jiang)，對(dui)于(yu)(yu)I類計量(liang)裝置，應(ying)(ying)不大于(yu)(yu)額定二(er)次(ci)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的0．2％（注：三(san)相(xiang)三(san)線(xian)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)壓(ya)(ya)(ya)降(jiang)(jiang)(jiang)的允(yun)許值為(wei)(wei)0．2 V；三(san)相(xiang)四(si)線(xian)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)壓(ya)(ya)(ya)降(jiang)(jiang)(jiang)允(yun)許值為(wei)(wei)0.2/V）;其(qi)它計量(liang)裝置，應(ying)(ying)不大于(yu)(yu)額定二(er)次(ci)電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)的0．5％（注：三(san)相(xiang)三(san)線(xian)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)壓(ya)(ya)(ya)降(jiang)(jiang)(jiang)的允(yun)許值為(wei)(wei)0．5 V；三(san)相(xiang)四(si)線(xian)電(dian)(dian)(dian)(dian)(dian)(dian)路(lu)壓(ya)(ya)(ya)降(jiang)(jiang)(jiang)允(yun)許值為(wei)(wei)0．5／V）。對(dui)運行(xing)中的電(dian)(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)互感器(qi)二(er)次(ci)回路(lu)壓(ya)(ya)(ya)降(jiang)(jiang)(jiang)需(xu)進(jin)行(xing)周期測試，以便算出由此(ci)引(yin)起的電(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)計量(liang)誤差，這對(dui)于(yu)(yu)進(jin)行(xing)技(ji)術改進(jin)，減小電(dian)(dian)(dian)(dian)(dian)(dian)能(neng)(neng)計量(liang)綜(zong)合誤差，降(jiang)(jiang)(jiang)低(di)計費損失有著重要意義(yi)

電壓互感器二次(ci)回路壓降測(ce)(ce)量(liang)(liang)方法(fa)(fa)通(tong)常(chang)有間(jian)接(jie)(jie)測(ce)(ce)量(liang)(liang)法(fa)(fa)和直(zhi)接(jie)(jie)測(ce)(ce)量(liang)(liang)法(fa)(fa)兩種（無線測(ce)(ce)量(liang)(liang)屬(shu)于間(jian)接(jie)(jie)測(ce)(ce)量(liang)(liang)法(fa)(fa)），由于間(jian)接(jie)(jie)測(ce)(ce)量(liang)(liang)法(fa)(fa)準確度不(bu)太(tai)高，不(bu)能(neng)滿足測(ce)(ce)量(liang)(liang)要求，一般(ban)不(bu)采用此種方法(fa)(fa)，而(er)直(zhi)接(jie)(jie)測(ce)(ce)量(liang)(liang)法(fa)(fa)（校驗(yan)儀測(ce)(ce)量(liang)(liang)法(fa)(fa)）采用測(ce)(ce)差原理(li)，準確度高，測(ce)(ce)量(liang)(liang)可(ke)靠，因此在實際測(ce)(ce)量(liang)(liang)中大量(liang)(liang)采用。

二次壓(ya)降對互(hu)感器誤差影(ying)響(xiang)說(shuo)明請參考下圖。

電(dian)流互感器(qi)的負(fu)荷(he)特性曲線

電壓互(hu)感器電壓與負(fu)荷特性

目前(qian)對(dui)(dui)互(hu)(hu)感(gan)(gan)器誤(wu)(wu)差測試(shi)時(shi)，通常按互(hu)(hu)感(gan)(gan)器銘(ming)牌上的規定用電流(liu)負荷(he)(he)箱和電壓負荷(he)(he)箱對(dui)(dui)互(hu)(hu)感(gan)(gan)器進(jin)行測試(shi)，但(dan)互(hu)(hu)感(gan)(gan)器運行過程中實際二(er)次(ci)負荷(he)(he)是(shi)多少？是(shi)不是(shi)就是(shi)互(hu)(hu)感(gan)(gan)器銘(ming)牌上規定值(zhi)？互(hu)(hu)感(gan)(gan)器在實際二(er)次(ci)負荷(he)(he)下(xia)的誤(wu)(wu)差是(shi)多少？

為了解決上述問(wen)題(ti)，實際測試互(hu)感器(qi)二次(ci)負荷就顯得特別重(zhong)要。同(tong)時(shi)在測試實際二次(ci)負荷過(guo)程中如何取樣電流信號也(ye)是比較重(zhong)要的(de)問(wen)題(ti)。在測試現場二次(ci)負荷時(shi)停電斷(duan)開電流回(hui)路既不方便也(ye)不安(an)全。我公司產品(pin)采(cai)用鉗型電流互(hu)感器(qi)（鉗表）對線路電流進行采(cai)樣，方便用戶(hu)使(shi)用。

另外有些公司產品采用(yong)(yong)取PT電(dian)(dian)壓作為儀(yi)器工作電(dian)(dian)源(yuan)，這種(zhong)(zhong)方(fang)(fang)式不是很安(an)全，在這種(zhong)(zhong)方(fang)(fang)式下，相當于給PT/CT增加了負荷，同(tong)時儀(yi)器變壓器的瞬間(jian)激(ji)磁電(dian)(dian)流(liu)很可能引(yin)起(qi)系(xi)統保護動作，影響供(gong)電(dian)(dian)安(an)全。我公司儀(yi)器采用(yong)(yong)大容量(liang)鋰(li)電(dian)(dian)池(chi)作為儀(yi)器工作電(dian)(dian)源(yuan)，既(ji)可以保障系(xi)統安(an)全又可以給儀(yi)器提供(gong)比較(jiao)純凈的電(dian)(dian)源(yuan)，避免現場電(dian)(dian)源(yuan)干擾(rao)，保證測(ce)量(liang)精度(du)。

我公司產(chan)品具有下列功能

1.可(ke)以實現三(san)相(xiang)三(san)線，三(san)相(xiang)四線、單(dan)相(xiang)全自動測量；

2.使用工程(cheng)塑料機(ji)箱(xiang)，結識(shi)耐(nai)用，有效保(bao)障(zhang)測試人員(yuan)及系(xi)統安全；

3.儀(yi)器具有量程自動切換(huan)功能(neng)，保證測試精度；

4.采用(yong)電子式原理線路結合DSP技術是使測(ce)試穩定性好，抗干(gan)擾(rao)強；

5.測量完畢，自動計算和負荷相(xiang)關的各(ge)項參數，便于客戶(hu)分析和試驗。

6.采用大屏幕漢(han)字(zi)液晶顯示，所(suo)有操作均由(you)漢(han)字(zi)菜單提示； 數(shu)(shu)據(ju)具(ju)備(bei)掉電存(cun)貯及瀏覽(lan)功能(neng)，能(neng)與計算機(ji)(ji)聯機(ji)(ji)傳送數(shu)(shu)據(ju)。

7.采用大容量7.2V11Ah鋰電(dian)池供電(dian)，對測試(shi)回(hui)路不產生任何(he)影響，避免系統出現保(bao)護的情況(kuang)(kuang)。同時在現場無供電(dian)電(dian)源的情況(kuang)(kuang)下使用。

8.自動切換量程：測(ce)量過程中(zhong)可以(yi)根據測(ce)試對象數值的不同切換到(dao)不同的位置，使(shi)測(ce)量精度和顯示位數得到(dao)保證。

9.作時間可(ke)以長達24小時（最長），可(ke)在充電(dian)狀態下測(ce)量。

10.附有輕(qing)巧充(chong)電(dian)器，方便測量，在(zai)電(dian)池電(dian)量不足的(de)情況下可以外接充(chong)電(dian)器測量。

11.儀器體(ti)積小(xiao)，重量輕。

12.極(ji)寬闊的(de)二次(ci)工(gong)作電(dian)(dian)(dian)流/電(dian)(dian)(dian)壓范圍。在50mA的(de)工(gong)作電(dian)(dian)(dian)流下，能(neng)分辨1mΩ的(de)電(dian)(dian)(dian)阻和(he)電(dian)(dian)(dian)抗，能(neng)測試(shi)二次(ci)額(e)定電(dian)(dian)(dian)流為5A的(de)S級電(dian)(dian)(dian)流互感(gan)器的(de)在線實際負(fu)荷；在5V的(de)工(gong)作電(dian)(dian)(dian)壓下，能(neng)分辨0.001mS的(de)電(dian)(dian)(dian)導和(he)電(dian)(dian)(dian)納。

13.能存儲480組測量數(shu)據，斷電后能保持十(shi)年。

14.中文(wen)界面大屏幕顯示，帶有RS-232通訊接口。

1

二、二次（PT）壓降測試儀主要技術指標

1、環境條件

——溫度：－5C～40C

——相對(dui)濕度：<95%（25C）

——海拔(ba)高度：<2500m

——外界(jie)干擾：無(wu)特(te)強震(zhen)動、無(wu)特(te)強電(dian)磁場

2、二次(ci)壓降測試時儀(yi)器主要技術指標

⑴.測量范圍：比差：0.001%～19.99% 角差：0.01’ ～599’

⑵.分 辨(bian) 率：比差：0.001%   角差：0.01’

⑶.儀器基本誤差

——X=(1%×X+1%×Y2個字);

——Y=(1%×X+1%×Y2個字)。

2個字——儀器的量化誤差

⑷.電壓表頭準確度：0.5%

⑸.工作范圍

——電壓(ya)：(50～120)V

⑹.儀器指(zhi)示動(dong)作值(zhi)(提示錯誤)

——誤差(cha)：比(bi)差(cha)大(da)于20%或角差(cha)大(da)于600’。

——電(dian)壓：電(dian)壓<2.0V。