電能計量裝置存在的誤差為電能計量綜合誤差，是由電能表的誤差、電壓互感器的合成誤差、電流互感器的合成誤差和電壓互感器二次導線壓降引起的計量誤差所組成，可以用以下式子表示：
ε=εw＋εTA＋εTV＋εr
式中 εw—電能表誤差%
εTA—電流互感器合成誤差%
εTV—電壓互感器合成誤差%
εr—電壓互感器二次導線壓降引起的計量誤差%
在(zai)電(dian)(dian)(dian)(dian)(dian)廠及變電(dian)(dian)(dian)(dian)(dian)站電(dian)(dian)(dian)(dian)(dian)能計量(liang)回(hui)路中，室(shi)外的(de)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)互感(gan)器(qi)(qi)(qi)離裝設于控制(zhi)室(shi)配電(dian)(dian)(dian)(dian)(dian)盤上的(de)電(dian)(dian)(dian)(dian)(dian)能表有(you)較遠的(de)距離，一般在(zai)200～400 m左右，整(zheng)個回(hui)路有(you)接(jie)線端(duan)子(zi)排、開關(guan)、熔斷器(qi)(qi)(qi)及導線，必然(ran)存(cun)在(zai)著接(jie)觸電(dian)(dian)(dian)(dian)(dian)阻、導線電(dian)(dian)(dian)(dian)(dian)阻及分布參數，從而(er)就存(cun)在(zai)著一定的(de)回(hui)路阻抗，造成電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)互感(gan)器(qi)(qi)(qi)與電(dian)(dian)(dian)(dian)(dian)能表間(jian)(jian)的(de)二(er)(er)(er)次回(hui)路上有(you)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降。電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)互感(gan)器(qi)(qi)(qi)二(er)(er)(er)次回(hui)路壓(ya)(ya)(ya)(ya)降包括電(dian)(dian)(dian)(dian)(dian)纜、端(duan)子(zi)接(jie)觸電(dian)(dian)(dian)(dian)(dian)阻、熔線、中間(jian)(jian)繼電(dian)(dian)(dian)(dian)(dian)器(qi)(qi)(qi)接(jie)點、空氣(qi)小開關(guan)等(deng)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降之(zhi)總和。電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)互感(gan)器(qi)(qi)(qi)二(er)(er)(er)次電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)降引起的(de)誤(wu)差(cha)，就是指電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)互感(gan)器(qi)(qi)(qi)二(er)(er)(er)次端(duan)子(zi)和負載端(duan)子(zi)之(zhi)間(jian)(jian)電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)幅值差(cha)相(xiang)對于二(er)(er)(er)次實(shi)際電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)的(de)百分數，以及兩個電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)(ya)(ya)之(zhi)間(jian)(jian)的(de)相(xiang)位差(cha)的(de)總稱(cheng)。

主要技術指標
環境條件
——溫度：－5?C～40?C
——相對濕度：<95%(25?C)
——海拔高度：<2500m
——外(wai)界干擾：無(wu)特強(qiang)(qiang)震(zhen)動、無(wu)特強(qiang)(qiang)電磁(ci)場

PT電流互感器二次回路負載測試儀主要技術指標
1). PT二次負荷測試
——導納測量范圍:0.1ms—50.0ms
——導納測量準確度:
——二次電壓(50V－120V)
?X=?(2%×X+2%×Y)?2個字
?Y=?(2%×X+2%×Y)?2個字
2個字——儀器的量化誤差
注意：測量值在0.2mS以下時，測試電壓應保持在50V以上，同時注意鉗表的穿心導線保持居中。此時儀器量化誤差為5個字
2). 電壓表頭(tou)：0.5%

CT電流互感器二次回路負載測試儀主要技術指標
——阻抗測量范圍：0.1Ω—50.0Ω
——阻抗測量準確度：
?X=?(2%×X+2%×Y)?2個字
?Y=?(2%×X+2%×Y)?2個字
2個字——儀器的量化誤差
電流表頭：1%