CVT二次绕组布置方式改善提高误差特性研究

Discussion and Verification on Improving Error Characteristic by Secondary Winding Layout of CVT

电容式电压互感器(CVT)作为一种功率测量计量用的电压信号取样装置,准确度是CVT的一个重要技术性能指标。通常CVT的准确度等级以该准确级在额定电压和额定负荷下所规定的最大允许电压误差百分数来标称的,他包括两个方面,即电压误差和相位差,计量和测量用准确级有0.2、0.5、1.0、3.0,保护用准确级有3P、6P。产品出厂例行试验准确度是按照现行国家标准,满足误差范围的相关要求。影响产品电压误差的因素有很多,针对客户特殊要求的多个0.2级准确等级的电容式电压互感器通过改变其中间变压器二次绕组的布置方式,以改变其绕组直流电阻来改善误差特性,通过验证对于同时拥有多个0.2级绕组产品准确度要求是可以满足的。

Accuracy of capacitive voltage transformer(CVT),a kind of voltage signal sampling device for power measurement and metering,is an important technical performance index of CVT.Generally,the accuracy class of CVT is denoted by the percentage of permissible maximum voltage error which is specified by the accuracy class at rated voltage and rated load.It includes such two aspects as voltage error and phase difference.The accuracy classes for measurement and metering are 0.2,0.5,1.0 and 3.0,and the those for protection are 3P and 6P.The accuracy of delivery routine test of the product is to meet relevant requirement of error range in accordance with the present China National Standard.The factors affecting the voltage error of the product are various.In this paper,by changing layout of the secondary winding of the intermediate transformer of CVT with multiple 0.2 accuracy class which is especially required by the customers,the error characteristic is improved by changing the DC resistance of its winding.It is proved through verification that the accuracy requirements of the product with multiple 0.2 class winding simultaneously can be met.