3电阻分压型电子式电压互感器的降低误差的措施 - 电测与仪表.doc

电阻分压型电子式电压互感器误差分析及对电能计量的影响研究 段梅梅1,2， （1.江苏省电力公司电力科学研究院，南京 211103） 摘要： 关键词： 中图分类号：TM933 文献标识码：B 文章编号： Research of the error of electronic voltage transformer based on resistance divider and its influence on electric energy metering , Li Zhen-hua3, Li Hong-bin3, Mu Xiao-xing1,2, Zhang Jian1,2 (1. Jiangsu Electric Power Company Research Institute, Nanjing 211103, China 2. State Grid Key Laboratory of Electrical Power Metering, Nanjing 211103, China 3. SEEE of Huazhong University of Science and Technology, Wuhan 430074, China) Abstract：electronic voltage transformer is the guarantee of safe and stable operation of power system and accurate measurement of power. Because the technology is not yet mature, some problems arise during the operation, among which the accuracy problem is the main problem. Currently, the study on the analysis of the factors which affect the accuracy of electronic instrument transformer is very few. For this reason, the error model of electronic voltage transformer based on resistance divider is created in this paper, and the impedance matching between the transformer and small analog signal power meter is analyzed. On this basis, the measures to reduce the transformer error are proposed, and it has a certain significance to improve the accuracy of electronic voltage transformer. Key words：resistance divider analog electronic voltage transformer, small analog signal power meter, impedance matching 0 引 言 [1-7]。电子式电压互感器的准确度关系着后续计量和保护设备的安全可靠运行。本文建立了电阻分压型模拟电子式电压互感器的误差模型，分析了影响电阻分压型模拟电子式电压互感器准确度的各类因素及其与模拟小信号电能表的阻抗匹配问题。在此基础上，提出了降低电子式电压互感器误差的措施。 1　电阻分压型电子式互感器的模型电阻分压电子式电压互感器的一个典型结构如图1所示[]。互感器主要由电阻分压器、传输系统和信号处理单元组成。电阻分压器由高压臂电阻R1、低压臂电阻R2和过电压保护的气体放电管3构成。电阻分压器作为传感器，将一次电压按比例转换为小电压信号输出。传输单元由双层屏蔽双绞线和连接端子构成，主要将分压器输出信号传递到信号处理单元，并屏蔽外界电磁干扰。信号处理单元主要由电压跟随、相位补偿和比例调节电路组成，实现电压互感器的阻抗变换、相位补偿和幅值调节功能，使互感器输出信号满足准确度要求。 图1 电阻分压型电子式电压互感器结构 图中1：高端金属屏蔽；2：树脂浇注；3：过压保护；4：低端金属屏蔽；5：屏蔽双绞线；6：信号处理装置。 图2 电阻分压原理图 对于串联电阻通过各电阻电流相等I=I1=I2= ….=In。总电压等于各电阻电压之和U=