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.
Electrical Measurement & Instrumentation