电容式电压互感器误差分析方法研究

Research on error analysis method of capacitor voltage transformer

电容式电压互感器(CVT)因具有耐电强度高,绝缘裕度大等特点,在110kV及以上电压等级的线路中被广泛应用于测量、保护等方面。随着厂、网分开,关口电能计量装置的准确性受到越来越多的关注。然而由于其CVT自身结构特点导致其在不同工作状态下误差结果往往差别较大。文章首先建立了CVT等效模型,从其结构原理、测量手段、外界环境等方面对其误差进行理论分析,得到误差变化趋势。其次以浙福工程中使用的CVT为例,对出厂误差测试、交接误差测试及在线误差测试数据进行比较并验证了理论分析的正确性。通过对CVT误差变化趋势的分析及验证试验,对现场交接试验及在线误差校准试验提供了指导依据,提高了CVT误差测量数据的可靠性。

The capacitor voltage transformer( CVT),which has advantages of dielectric strength and insulation margin,and it is widely used at 110kV and above voltage level power system on error measurement,system protection and so on. With the separation of power plants and transmission grid,people have been paid much more attention on accuracy of gateway energy metering device. Actually,the error data often vary greatly with different working conditions because of the structural characteristics of CVT. Firstly,the equivalent model has been established by considering the structural principle of CVT,measuring instruments and external environment to conduct theoretical analysis for its error. Secondly,this paper takes CVTs which are used at Zhe Fu project for example to contrast error data of delivery test,commissioning test and online error calibration. Then,these measured data have proved the correctness of the theoretical analysis. The analysis of CVT error data trend and validation tests provides guidance for commissioning test and online error calibration. What's more,it improves the reliability of CVT error measurement.