电力系统中电子式电压互感器的误差特性研究与参数优化设计

通过分析电容分压型电子式电压互感器(electronic capacitive voltage transformers,ECVT)的传感原理和工作环境,建立了电力系统中ECVT的数学模型,指出影响互感器精度的重要因素是分布杂散电容的存在,并运用电路理论分析该电容分压器的误差特性,诠释了杂散电容和相间干扰引起ECVT测...

Study on Error Characteristics of EVT in Power System and Optimum Design of EVT Parameter

Sensing principles and operation environment of electronic capacitive voltage transformers(ECVT) were analyzed to set up a mathematical model of ECVT in the electric power system,which indicates that the main factor influencing the accuracy of sensor is the existence of distributed stray capacitance.Circuit theory was adopted to analyze the error characteristics of capacitive divider in the model and demonstrate the mechanism how the stray capacitance and interphase interference cause measuring error of ECVT.FEA software was applied to establish a structure FEA algorithm model for ECVT capacitive divider in 220 kV system,and the simulation of electrostatic field in this model was utilized to work out the distributed stray capacitance matrix.In the end,this paper optimized the major parameters of the capacitive divider via the algorithm model.The analysis and optimization results show that ECVT can reach accuracy of Grade 0.2 when the rating capacitance of capacitive divider is not smaller than 3 500 pF.