王欢,项琼,冯宇,徐思恩,朱凯,余也凤.偏心及返回导体对特高压用计量CT误差影响分析[J].电测与仪表,2018,55(3):116-122. Wang Huan,Xiang Qiong,Feng Yu,Xu Sien,Zhu Kai,Yu Yefeng.Analysis of error of measurement current transformers in the UHV under primary winding eccentricity and return conductor influence[J].Electrical Measurement & Instrumentation,2018,55(3):116-122.
偏心及返回导体对特高压用计量CT误差影响分析
Analysis of error of measurement current transformers in the UHV under primary winding eccentricity and return conductor influence
In order to make clear the influence of the error of electric energy metering device with electromagnetic interference, a quantitative analysis of error with the primary winding eccentricity and the return conductor on CTs had been developed on the measurement CTs in UHV project. Firstly, the error mathematical model of CTs had been established in cylindrical coordinates by the principle of magnetic circuit balance in order to find the error change of CTs with applied magnetic field at different positions. Secondly, a simulation of two-dimensional electric field had been done with typical size and primary current of measurement CTs in 1000kV engineering. It can be found by this simulation that the local saturation will occur when the primary winding offset distance from the center of CTs greater than 1/8 radius, and the error changes greatly which leads to the possibility of excess error limit. In addition, the simulation results indicate that the interference of the magnetic field caused by the return conductor to CTs error can be ignored when the return conductor distance to the CT center greater than 3 times of CTs’ radius. Finally, a test loop hand been built to obtain the error data with deviation of primary winding of CTs. The experimental data are consistent with the simulation results on the problem of primary winding deviation.
